Haghani, M., Cristiani, E. , Bode, N., Boltes, M., & Corbetta, A. (2019). · Haghani, M.,...

Haghani, M., Cristiani, E., Bode, N., Boltes, M., & Corbetta, A. (2019).Panic, irrationality, herding: Three ambiguous terms in crowd dynamicsresearch. Journal of Advanced Transportation, 2019, [9267643].https://doi.org/10.1155/2019/9267643

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https://doi.org/10.1155/2019/9267643

https://doi.org/10.1155/2019/9267643



Review ArticlePanic, Irrationality, and Herding: Three Ambiguous Terms inCrowd Dynamics Research

Milad Haghani ,1 Emiliano Cristiani,2 Nikolai W. F. Bode,3

Maik Boltes,4 and Alessandro Corbetta5

1 Institute of Transport and Logistics Studies, The University of Sydney Business School, The University of Sydney, Australia2Istituto per le Applicazioni del Calcolo “M. Picone”, National Research Council of Italy, Rome, Italy3Department of Engineering Mathematics, University of Bristol, Bristol, UK4Forschungszentrum Julich, Julich, Germany5Eindhoven University of Technology, Eindhoven, Netherlands

Correspondence should be addressed to Milad Haghani; [email protected]

Received 4 April 2019; Revised 7 June 2019; Accepted 1 July 2019; Published 8 August 2019

Academic Editor: David F. Llorca

Copyright © 2019 Milad Haghani et al.This is an open access article distributed under the Creative Commons Attribution License,which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Background. The three terms “panic”, “irrationality”, and “herding” are ubiquitous in the crowd dynamics literature and have astrong influence on both modelling and management practices. The terms are also commonly shared between the scientific andnonscientific domains. The pervasiveness of the use of these terms is to the point where their underlying assumptions have oftenbeen treated as common knowledge by both experts and lay persons. Yet, at the same time, the literature on crowddynamics presentsample debate, contradiction, and inconsistency on these topics.Method. This review is the first to systematically revisit these threeterms in a unified study to highlight the scope of this debate. We extracted from peer-reviewed journal articles direct quotes thatoffer a definition, conceptualisation, or supporting/contradicting evidence on these terms and/or their underlying theories. Tofurther examine the suitability of the term herding, a secondary and more detailed analysis is also conducted on studies that havespecifically investigated this phenomenon in empirical settings. Results. The review shows that (i) there is no consensus on thedefinition for the terms panic and irrationality and that (ii) the literature is highly divided along discipline lines on how accuratethese theories/terminologies are for describing human escape behaviour.The review reveals a complete division and disconnectionbetween studies published by social scientists and those from the physical science domain and also between studies whose mainfocus is on numerical simulation versus those with empirical focus. (iii) Despite the ambiguity of the definitions and the missingconsensus in the literature, these terms are still increasingly and persistently mentioned in crowd evacuation studies. (iv) Differentto panic and irrationality, there is relative consistency in definitions of the term herding, with the term usually being associatedwith‘(blind) imitation’. However, based on the findings of empirical studies, we argue why, despite the relative consistency in meaning,(v) the term herding itself lacks adequate nuance and accuracy for describing the role of ‘social influence’ in escape behaviour.Our conclusions also emphasise the importance of distinguishing between the social influence on various aspects of evacuationbehaviour and avoiding generalisation across various behavioural layers. Conclusions. We argue that the use of these three terms inthe scientific literature does not contribute constructively to extending the knowledge or to improving the modelling capabilitiesin the field of crowd dynamics. This is largely due to the ambiguity of these terms, the overly simplistic nature of their assumptions,or the fact that the theories they represent are not readily verifiable. Recommendations. We suggest that it would be beneficial foradvancing this research field that the phenomena related to these three terms are clearly defined by more tangible and quantifiableterms and be formulated as verifiable hypotheses, so they can be operationalized for empirical testing.

1. Introduction

As researchers working in the field of pedestrian dynamics,we have experienced that a presentation of a piece of research

on the topic of crowd evacuation, whether to an academicaudience or lay audience, barely goes by without researchersbeing confronted with these questions: How about the effectof panic? How do you model/experiment panic? To a lesser

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2 Journal of Advanced Transportation

extent, we also similarly receive questions of this natureduring peer review processes. The question is also oftenaccompanied by follow-up questions on irrational behaviourduring evacuations and herding phenomena and how wetake those into account in our computational models orexperimentations.

We have also observed that these debates are oftennot resolved with a rigorous argument based on facts andempirical evidence and are, rather, addressed with somelevel of speculation and resorting to intuition. Nevertheless,researchers often concede that these might be limitationsof their study and phenomena that they still have not beenable to tackle. Sometimes, researchers take a more defensiveposition facing this question and present counterargumentsthat are meant to dismiss these phenomena as mattersthat should not concern us when designing our researchexperiments or formulating our models.

The question that arises is why, after so many years ofresearch in this field, have these terms remained intractable?Does this stem from a lack of clear definitions and/or a lack ofwell-conditioned theoretical conceptualisation? Is this a signthat these terms are still not well defined and that they may,to some degree, be misdirecting the research in this field?

The issue of panic constitutes a rather frequent disclaimerat the discussion section of publications on crowd evacuationdynamics and a common ground for criticising themodellingand experimentation efforts in this field [1]. Such disclaimersoften appear in wordings such as: These experiments wereconducted under nonpanic conditions [2], or the influence ofpanic has been excluded from the experiment/model [3, 4].This gives the indication that simulating/modelling panic isgoing to be a future development in this field something thatthe research is headed towards, but one that we have not beenable to tackle just yet.

What is, however, very clear is that the terms, panic, irra-tionality, and herding are among the most ubiquitous termsin the crowd dynamics literature. A peculiar characteristicis that they are used as commonly shared language betweenthe scientific literature, the public, and the media to describecollective evacuation behaviour [5]. As stated by Quarantelli[5], “what constitutes panic is illustrated by presentationsof anecdotal examples from stories of disaster behavior injournalistic and popular sources”. Here, we investigate whatlevel of consensus exists on their definition and meaning. Wesurvey the scientific literature of crowd dynamics and analysethe use of these three terms with the aim of identifying(i) whether the literature offers unified definitions, (ii) howdifferent segments of the literature view these terms andtheir theories in general, (iii) how well supported they arein various segments of the literature, and (iv) how theycan potentially influence experimentation, modelling, andmanagement practices in this field.

2. Methods

The main purpose of the review is to perform a structuredliterature search on the use of the terms panic, irrationality,and herding in the context of emergency evacuation of

crowds.This will help to establish whether unified definitionscan be identified, and it will identify possible inconsistenciesor contradictions. In performing this analysis, we also aimto provide an overall reflection of how different researchfields perceive each of these terms. The literature review putstogether studies froma range of disciplines including physicalsciences, social sciences, and biological sciences.

The structured literature analysis is mainly performedon direct quotes from peer-reviewed research articles wherethese terms have appeared. The main criterion for theselection of the underlying studies was that they had tobe exclusively in the context of emergency behaviour, andparticularly the behaviour of humans within crowds. Forexample, the use of the term herding in financial or othercontexts where the term is frequently used is not consideredhere.

Using Scopus as our primary database, we performedtitle-keywords-abstract searches by applying all possiblecombinations between the terms “pedestrian, evacuation,crowd, escape, disaster, emergency”, and the set of three focusterms of this study “panic, irrational, herd” while separatingthem by the operator “AND”. Each search outcome waslimited to Articles and Reviews as Document Types, andexclusively Journals as Source Types. No particular date wasspecified. This search was initially performed in August 2018.It was subsequently updated in January 2019, limiting theoutputs to 2018 and 2019 as Year of publication. For eachsearch, the outputs underwent an initial screening to identifythe relevant articles.This screeningwas performedfirst on thetitle of the articles that appeared in search outputs and then ontheir abstract and keywords only if necessary (i.e., only if thetitle did not give clear indication of whether the study wouldbe potentially relevant to the content of the review). Thesearch was also supplemented by a prior and less systematicsearch on a personal reference database that includes nearly2000 selected articles in the context of crowd dynamics, aswell as a variety of Google Scholar searches using similarcombination of terms used in Scopus.

This process generated a shortlist of nearly 200 articleswhose full texts were screened for the purpose of extractingquotes relevant to the context of this review. The full textof each article was searched for the use of the terms ‘panic’,‘irrational(ity)’, and ‘herd(ing)’ separately. The criteria forchoosing quotes where these terms appeared were that thequote has to convey some form of definition on the term,characterise the term (or its underlying phenomenon), ormake some comment on the validity of their underlyingtheory or the commonness of the phenomenon real-lifeemergencies. We use these broad inclusion criteria to achievea comprehensive and objective perspective on how theseterms are perceived and used in various subdivisions of theliterature.

Out of the nearly 200 shortlisted articles whose full textswere analysed for the use of these terms, half of them (101items) produced at least one quote that met our criteriaoutlined above.These quotes were extracted from each articleand were stored in separate Word files for further subsequentanalyses. In the subsequent analyses, mainly for the purposeof keeping this review to a reasonable length, quotes within

Journal of Advanced Transportation 3

studies that had produced more abundant material had tobe prioritised. In such cases, where a study had producedseveral and often lengthy quotes relevant to our review topic,the quotes with similar content were compared together andbriefest ones were chosen. Also, for quotes in which morethan one of the three terms had appeared, the quote wasonly categorised in one of the three sections related to theseterms by identifying the term that was dominant in the quote(i.e., the term that constituted the primary theme of thequote). This way, we avoided repeating individual quote forthe analyses on our three terms.

The selected quotes were subsequently further analysedand categorised. We differentiated between the quotes interms of whether they offer a definition/characterisation onthe term or just comment on the commonness/likelinessof the underlying phenomenon. Where possible we alsorecorded whether the quote sentiment is in support of theunderlying theory or the use of the term, or instead, contra-dicts or rejects that idea. Also, in order to demonstrate howintertwined these terms are within the scientific literature,we recorded when the quote links (at least) two of the threeterms together. We categorised the source study of eachquote into one of the three main disciplines, social sciences,physical sciences, and biological sciences. This categorisationis predominantly based on the discipline of journal that haspublished the study as well as the main theme of the study.In most cases, these criteria aligned with one another, but incases where one single categorisation was not possible, morethan one category was assigned to the source article. This cat-egorisation was primarily meant to indicate whether and howthe perception of these three terms varies across researchersfrom different disciplines. The studies that we surveyed hadone (or sometimes more) of these three themes as their mainfocus: modelling, empirical testing, and conceptualisation.We categorised each quote based on the primary categoryof its underlying study among these three categories. Oftenmore than one category were applicable to the source studyof a quote. In those cases, we allowed belonging to morethan one category. The purpose of this categorisation was toidentify whether there is a noticeable difference in definitionand/or perception of our three terms of interest across studieswhose main focus is on modelling compared to empiricalstudies or those that only conceptualise these phenomena.Although this is a somewhat crude categorisation of studiesand should be interpreted as such, we suggest that it facilitatessome coarse insights. The quotes that we extracted fromindividual studies were quite diverse. However, we wereable to identify common themes across clusters of thesequotes. Therefore, to further summarise and categorise theseindividual quotes, we identified these common themes andadded them as short comments to each quote. In caseswhere the quote did not fit any of those common themes nocomments were added to the quote.

The outcome of the analysis outlined above is sum-marised and reported in Tables 5, 6, and 7, respectively,for terms panic, irrationality, and herding. For each quotelisted in these tables, the source reference from which thequote has been extracted is cited. The table also determineswhether the quote links each term to either (or both)

of the two other terms. It also determines whether thequote offers any definition or conceptualisation on this term(when applicable) and whether it conveys support for thepanic/irrationality/herding theory or challenges/contradictsit (when applicable). Then, in order to identify how thesecharacteristics of the quotes are influenced by the disciplinefrom which the study originated, the source reference of thequote is categorised in one (or, occasionally, two) of the threedisciplines: social sciences, physical sciences, and biologicalsciences.The source reference is also categorised based on thenature of the study. If the study is heavily focused on numer-ical simulation and modelling without much connection toempirical analysis, then it is categorised as a “modelling” typestudy. If the study presents noticeable empirical componentsit is categorised as “empirical testing”. If the study only offersconceptualisation on this term or its underlying theory, thenit is categorised as a “conceptualisation” study. Occasionallysome studies had to be categorised in more than one of thetwo study types.

In order to establishwhether ‘herding’, as a terminology, issuitable and accurate enough for describing the phenomenathat it is meant to embody, it seemed necessary to examinethis term based on the findings of empirical studies. There-fore, we decided to perform a supplementary survey on theherding phenomenon in evacuation exclusive to the studiesthat have experimented this question in one form or another.This supplementary survey is not based on the analysis of thequotes per se, rather than concerns the individual studies,those that have provided experimental findings on herdingbehaviour in evacuations. In collecting a comprehensiveset of references related to this supplementary survey, wefirst extracted relevant studies from a previous review ofthe empirical studies in crowd dynamics whose referencedatabase was last updated in April 2017 [6]. In order to iden-tify studies that were published after April 2017 we conductedsupplementary search inGoogle Scholar and Scopus, with themain selection criterion being that the experiment report onsome form of empirical testing or experimentation on thetopic. In total, 24 articles qualified for this supplementaryliterature analysis. The supplementary analysis allowed us tofocus deeper on the herding phenomenon beyond the use ofterminology by assembling all existing empirical findings todate. Our conclusions and recommendations regarding thesuitability of the term herding are mostly grounded in thissecondary analysis.

3. Quotes on the Term ‘Panic’The original quotes on the term panic have been listed andanalysed in Table 5 in Appendix. The extracted quoteson the term panic were subsequently analysed and afteridentifying the common themes across the quotes; theywere categorised into 22 reduced comments. Table 1 liststhese reduced comments along with the frequency of theiroccurrence in the original comments extracted on the termpanic. The table also shows how many times each theme hasbeen repeated in studies across the three different disciplineswe considered (i.e., social sciences, physical sciences, and


Table1:Re

ducedcommentson

theterm

panica

ndtheirfrequ

ency

amon

gtheo

riginalqu

otes.

No.

Com

ment

Frq.

Disc

iplin

eStud

ytype

Soc.

Phys.

Bio.

Mod

.Em

p.Test.

Con

c.1

Panicisc

ommon

occurrence

inthefaceo

fimminentd

anger

41

30

31

02

Panicisa

very

pervasivea

ssum

ptionin

mod

ellin

gliterature

66

00

01

63

Panicisrareo

ccurrenceinthefaceo

fimminentd

anger

10

10

10

04

Panicisa

causeo

finjuriesincrise

s13

310

07

26

5Panicc

anaffectevacuationeffi

ciency,inbo

thbeneficialord

etrim

entalw

ays

10

10

10

06

Panicc

anaffectevacuationeffi

ciency

71

60

40

37

Panicism

anifeste

das

rand

om(erratic)b

ehaviour

(chaos)

41

30

20

28

Panicism

anifeste

das

increasedstr

ess(nervou

sness/fear)

62

40

41

49

Panicism

anifeste

das

imitativ

e(herd)b

ehaviour

71

60

71

210

Panicism

anifeste

das

elevated

physicalcompetition

91

80

80

311

Panicism

anifeste

das

non-hu

manisticbehaviou

r5

41

00

14

12Panicc

anoccurw

ithou

tany

disting

uishablecause

10

10

10

013

Paniclacks

aclear

defin

ition

1211

10

14

1114

Panicisc

ommon

medialang

uage

65

10

12

515

Panicc

anbe

representedby

simplep

aram

etersinsim

ulationmod

els

40

40

40

116

Panictheorylackse

mpiric

alsupp

ort

2722

50

410

2317

Panicleads

toim

balanced

utilisatio

nof

exits

31

20

00

318

Panicleads

toexitblockages

60

60

60

219

Therea

revario

uskind

sofp

anic

42

20

22

420

Socialaffi

liatio

ntheory

presentsan

alternativetothep

anictheory

77

00

02

621

Panictheoryhassignificantimplications

forc

rowd

managem

ent

33

00

00

322

Whatseemstobe

panicb

ehaviour,m

aybe

individu

al’sb

estp

erceived

courseof

actio

n2

20

00

02

“Frq.”indicatesfrequency.

“Soc.”,

“Phys.”,and

“Bio.”,

respectiv

ely,indicatesocia

lscie

nces,physicalsciences.and

biologica

lscie

nces.

“Mod

.”,“Emp.Test.”,and“C

onc.”

,respectively,indicatemodelling,em

piric

altesting,and

conceptualisa

tion.


Cont. P.

Cont. P.

Supp. P.

Supp. P.

Soc.Phys.Bio.

Mod.Emp. Test.Conc.

Soc.Phys.Bio.

Mod.Emp. Test.Conc.

05

101520253035404550

Freq

uenc

y

Figure 1: Visualising the frequency of quotes on the termpanic that convey support for the theory versus those that challenge it.The pie chartson the left show the frequency of the supporting comments across the disciplines (on the top) and across the study types (in the bottom).Similarly, the pie charts on the right show the frequency of the contradicting comments again across the disciplines (on the top) and across thestudy types (in the bottom). The column chart in the middle compares the frequency of these comments in total regardless of the disciplineor type of the study from which the comments were extracted.

biological sciences) as well as across the three different studytypes that we considered (i.e., modelling, empirical testing,and conceptualisation). Figure 1 visualises the frequency ofthe quotes that indicate support for the panic theory versusthose that challenge (or contradict) the theory, again acrossdisciplines, and across study types. Figure 2 illustrates theoutcome of a temporal analysis on the frequency of thequotes.

One of the most recurring themes in the extractedcomments on the term panic concerns the fact that thetheory of panic is not well supported by empirical testing[7, 8] (comment #16 in Table 1). Out of nearly 112 commentsextracted on the term panic, this theme repeated 27 times.According to Table 1, the majority of such comments orig-inated from studies in the social sciences. Another themethat was very common among the quotes was statementsindicating that panic in and of itself is a major cause of injuryin emergency incidents and crises and can aggravate the harmcaused by the actual crisis [9, 10]. Quotes of this nature wererepeated in 13 cases according to Table 1 (comment #4) andthe majority of the quotes originated from modelling-typestudies published within the domains of physical sciences.Third in this ranking was a noticeable set of quotes thatpointed out to a major problem regarding the use of panic inevacuationmodelling; the fact that the literature has so far notbeen able to produce a unified definition for the term panicand that has left the theory of panic largely unverifiable andsubject tomere speculation and debate [11, 12].This comment(#13 in Table 1) was repeated in 12 cases in the quotesextracted on the term panic and again is one of the areas

along which the social and physical science studies divide.The vast majority of the quotes that pointed this issue outwere obtained from the social science and conceptualisationstudies whereas modelling studies have largely downplayedthis problem. This highlights a major problem for modellingpractice that aim to represent the so-called panic behaviourin their modelling formulations. In the absence of a cleardefinition on what panic means, efforts to mathematicallyrepresent it in the models will largely be subject to theinterpretation of the modeller. In addition, even in thedomain of social sciences, panic has a very broad definitionranging from aspects such as extreme emotions, groundlessfear, uncontrolled flight behaviour, impatience, the quicktransmission of excessive fear (i.e., emotional contagion), orthe disappearance of normal social bonds [13]. According toQuarantelli [5], early definitions in sociology textbooks andarticles view panic as “the crowd in dissolution” or “collectiveflight based on a hysterical belief” or “dysfunctional escapebehavior generated by fortuitous, ever varying circumstances,but involving impending danger”. The author also continuesto point out that “early approaches to panic were vaguein defining the phenomena. However, most formulationsview panic as either extreme and groundless fear, or flightbehavior”.The inconsistency and the variety of the definitionsmake the practice of integrating them with predictive models(as aimed by physical scientists working in this domain)morearbitrary and rather subjective.

Of those studies that attempted to offer some defini-tions on the term panic, we found quotes indicating thatpanic refers to random, unhinged and erratic behaviour [14]


1993

-1997

1998

-2002

2003

-2007

2008

-2012

2013

-2018

0

10

20

30

40

No.

of q

uote

s

1993

-1997

1998

-2002

2003

-2007

2008

-2012

2013

-2018

Soc.Phys.Bio.

05

101520253035

No.

of q

uote

s

1993

-1997

1998

-2002

2003

-2007

2008

-2012

2013

-2018

Cont. P.Supp. P.

0

5

10

15

20

25

30

No.

of q

uote

s

Figure 2: Visualising temporal analyses on quotes that include the term panic. The column chart on the top represents the total number ofquotes and the one in the bottom splits the frequency based on whether the quotes support or contradict the theory (chart on the left) andbased on the study discipline (chart on the right). To account for the fact that the last time interval includes 6 years as opposed to the rest ofthe time intervals that include 5 years, the numbers associated with the last interval have been scaled down by a factor of 5/6. The very fewstudies covered by this review and published prior to 1993 or in 2019 we accommodated in the first and last intervals, respectively.

(comment #7 in Table 1), comments that referred to panicsimply as an extreme state of fear or stress during emergencies[11] (comment #8 in Table 1), and also those that describedpanic manifested as nonhumanistic behaviour [15], imitativebehaviour [16], or physically competitive behaviour [17]. Itis unlikely that all these conditions can exist at the sametime which suggests the theory of panic is not clearly definedand has remained so for many years. The mere fact thatmodellers try to represent panic using model parameters [18]per se contradicts the idea that panic means people showingrandom behaviour, because something that is completelyrandom cannot be modelled or predicted. Also, the idea thatpanic is accompanied by an increased tendency to follow thecrowd [19] further contradicts the idea of random behaviour,because following the majority is itself a strategy and is not arandom act.

The social identity and the affiliative behaviour theory [13,15] proposed by social scientists present arguments againstthe point of view of the mass panic theory as selfish anduncontrolled behaviour. In contrast to the panic theory, socialpsychologists have in recent years developed and tested aconceptual model of affiliative collective behaviour in emer-gencies and disasters that explains how “a sense of commonfate is the source of an emergent shared social identity among

survivors, which in turn provides themotivation to give socialsupport to others affected”. [13]

Similarly, the studies that attribute the inefficiency ofcrowd evacuation behaviour and the occurrence of exitblockages to the increased physical competitiveness causedby panic have also been challenged by recent empiricalwork that suggests increased physical competition does notnecessarily translate to inefficient egress processes [20–22].Related to this interpretation (or manifestation) of panicbehaviour, Heliovaara, Ehtamo, Helbing, and Korhonen [23]have pointed out that “In the literature of social psychology,the pushing behavior is often related to panic. Panic occursin situations of scarce and dwindling resources and panickingpeople tend to behave irrationally and adopt a selfish attitude.However, there has been a consensus for decades that actualpanic occurs rarely in real crowds and evacuating people tendto behave rationally”.

Another common theme that does not come at the top ofthe list in terms of the frequency of repeating in the quotesbut points to an important problem is comment #21 whichrecognises that “panic theory has significant implicationsfor crowd management” [24]. It pertinently reminds us ofthe implication that the term panic and the assumptionsthat it implies may have on how managers and emergency


Cont. Ir.

Cont. Ir.

Supp. Ir.

Supp. Ir.

Soc.Phys.Bio.

Mod.Emp. Test.Conc.

Soc.Phys.Bio.

Mod.Emp. Test.Conc.

05

1015202530

Freq

uenc

y

Figure 3: Visualising the frequency of quotes on the term irrationality that convey support for the theory versus those that challenge it. Thepie charts on the left show the frequency of the supporting comments across the disciplines (on the top) and across the study types (in thebottom). Similarly, the pie charts on the right show the frequency of the contradicting comments again across the disciplines (on the top) andacross the study types (in the bottom). The column chart in the middle compares the frequency of these comments in total regardless of thediscipline or type of the study from which the comments were extracted.

responders decide to communicate information to the crowdin incidents of emergency. It recognises that this assumptionmay be used as a justification to withhold information fromthe crowd in order to avoid panic andminimise the harm thatit may cause. As Heide [25] has pointed out, “The problemwith the panic misconception is that the public, the media,and even emergency planners and public officials believeit. Because of this, officials may hesitate to issue warningsbecause they are convinced that the resulting panic will causemore damage than the disaster itself”. He also continuesthat “this belief has led to recommendations to avoid panicby (1) providing minimal information to occupants in theevent of a building fire and (2) carrying on normal activ-ities until the last possible moment”. Similar concern hasbeen voiced by Proulx [26] who has stated that “Duringemergencies, the anticipation of mass ‘panic’ has been afavoured argument to delay warning the public”. This groupof studies that pointed to this problem argue extensivelythat withholding information frompotential evacuees cannotreasonably be the best course of action in emergencies[24, 25].

The plots presented in Figure 1 provide an illustrationof the divide that exists between social science and physicalscience studies on how they view the term panic. While thequotes extracted in this review show a relatively balancedsplit in terms of the number of quotes that support thetheory of mass panic versus those that contradict it, aclear difference is noticeable when a comparison is madeacross the disciplines or across the study types. According to

these plots, while the majority of the quotes obtained fromstudies in the domain of physical sciences (mostly, modellingstudies) treat the existence of panic as a proven fact, thesituation is completely reverse when one considers the quotesextracted from the studies published by social scientists onthis topic. Modelling studies have predominantly tried torepresent a partial representation of what is known as panicbehaviour in their mathematical formulations using simpleparameters (that make agents show more noisy behaviour,or more imitative behaviour or more physically competitivebehaviour) while assuming panic and its characterisation asproven by their predecessor studies, whereas social scientistshave placed a heavier focus on identifying empirical evidencethat supports the idea of collective panic behaviour in massemergencies and have in most cases failed to observe suchevidence [27, 28].

The temporal analysis presented in Figure 2 furtherhighlights this disconnect between disciplines in how theyview the term panic. It further illustrates that, despite theincreasing debate on the appropriateness of this term inevacuation literature, the term is increasingly appearing in thescientific literature. According to the set of quotes extractedin this review, while the use of the term among these quotesshows a relatively stable pattern that the social science studiesin terms of the frequency of mention, its frequency of beingmentioned has surged among the modelling studies. It isalso interesting to note, at least among the quotes that wereextracted here, that there is no mention of the term panic inphysical science studies published prior to year 2000.


1993

-1997

1998

-2002

2003

-2007

2008

-2012

2013

-2018

0

5

10

15

No.

of q

uote

s

1993

-1997

1998

-2002

2003

-2007

2008

-2012

2013

-2018

Soc.Phys.Bio.

02468

101214

No.

of q

uote

s

1993

-1997

1998

-2002

2003

-2007

2008

-2012

2013

-2018

Cont. Ir.Supp. Ir.

0

2

4

6

8

10

No.

of q

uote

s

Figure 4: Visualising temporal analyses on quotes that include the term irrationality.The column chart on the top represents the total numberof quotes and the ones in the bottom splits the frequency based on whether the quotes support or contradict the theory (chart on the left) andbased on the study discipline (chart on the right). To account for the fact that the last time interval includes 6 years as opposed to the rest ofthe time intervals that include 5 years, the numbers associated with the last interval have been scaled down by a factor of 5/6. The very fewstudies covered by this review and published prior to 1993 or in 2019 we accommodated in the first and last intervals respectively.

4. Quotes on the Term ‘Irrationality’

The original quotes extracted on the term irrationality arelisted in Table 6 in Appendix where similar type of catego-risation has been conducted to that of the panic termas explained in the previous section. These quotes werecategorised subsequently into 11 common themes presentedas reduced comments on the term irrationality in Table 2.Figure 3 provides a visual illustration of the frequency of thecomments on the term irrationality based on the total setof comments, the discipline of their origin and the type oftheir study of origin. And Figure 4 provides the outcome ofa temporal analysis on these comments based on the year ofpublication for their study of origin.

The most common theme that was observable amongthe quotes that were extracted in this work were thosethat attribute irrationality very closely to panic, by statingthat making irrational decisions is one of the aspects ofcollective panic (comment #1 in Table 2) [29]. In otherwords, these were the comments which suggest that panicimplies irrational behaviour too. According to Quarantelli[5], for example, “present day discussions about panic alsorevolve around whether or not the behavior is irrational,and whether it is highly contagious or not”. We also founda relatively substantial number of quotes challenging the

theory of irrationality and stating that the theory cannotbe regarded as an accurate and verifiable description of abehavioural phenomenon in the face of threats [15, 30, 31].This comment was the second most common in the list ofreduced comments on irrationality (comment #7).

Another group of statements pointed to a set of veryimportant dimensions which are often neglected in discus-sions of the topic of irrational behaviour and that includes (1)irrational from whose perspective and (2) irrational relativeto which reference point. These statements are collectivelyreflected in comments #9, 10, and 11. As pointed out byDrury, Novelli, and Stott [24], “To judge a response asirrational requires a frame of reference, but the frame ofreference is often unclear in a mass emergency”. Therefore,it is not sufficient to merely talk about the rationality ofhuman responses without measuring the effectiveness of theresponse relative to a proper reference point and that is anelement that is often missing from the discussions on thistopic. How such a reference point can be set and how theefficiency or rationality or optimality of behaviour can bemeasured against it is certainly a matter of research in thisarea [32], but its necessity seems to be indisputable. Furtheron that issue, a considerable number of studies that werereviewed pointed out that what seems an irrational act maybe an individual’s best perceived course of action. Drury,


Table2:Re

ducedcommentson

theterm

irrationalitya

ndtheirfrequ

ency

amon

gtheo

riginalqu

otes.

No.

Com

ment

Frq.

Disc

iplin

eStud

ytype

Soc.

Phys.

Bio.

Mod

.Em

p.Test.

Con

c.1

Irratio

nalb

ehaviour

isas

ymptom

ofpanic

109

10

11

92

Herding

isas

ignof

irrationalbehaviour

41

30

30

13

Choo

singfamiliar

exits

isas

ignof

irrationalbehaviour

10

10

10

04

Peop

lecanmaintainratio

nalityd

uringcrise

s3

03

02

11

5Irratio

nalitymeans

deciding

rand

omly

10

10

10

06

Ratio

nalityisassociated

with

evacuatio

neffi

ciency

73

31

30

57

Irratio

nalityisno

tanaccuratetheory

fore

vacuationbehaviou

r9

90

00

29

8Irratio

nalitytheory

hassignificantimplications

forc

rowd

managem

ent

66

00

00

69

Measurin

gratio

nalityr

equiresa

referencep

oint

33

00

00

310

Whatseemsirrationalact,m

aybe

individu

al’sb

estp

erceived

course

ofactio

n7

61

00

26

11Irratio

nalitylacksa

cleard

efinitio

n1

10

00

11

“Frq.”indicatesfrequency

“Soc.”,

“Phys.”,and

“Bio.”,

respectiv

ely,indicatesocia

lscie

nces,physicalsciences,and

biologica

lscie

nces.

“Mod


onc.”


piric

altesting,and

conceptualisa

tion.


Novelli, and Stott [24] stated that “Fleeing, fear, screamingor other responses to perceived danger may therefore beentirely reasonable [rational] given the limited information– and limited choices – available to people in the midst ofan emergency”. In a more recent study, Drury [13] furtherelaborates on the importance of taking into considerationwho judges the behaviour as irrational. He points out that“what appears post hoc and from an external perspective tobe an overreaction (such as running frantically following abomb blast) might be reasonable and proportionate from theperspective of those involved”. Similarly, Kelley, Condry Jr,Dahlke, and Hill [33] mentioned that “The individual is noless rational or moral in the panic than in any other situation.He is always in pursuit of his own interests and acts onthe basis of his current estimates of where these lie”. Thecomment by Sheppard, Rubin, Wardman, and Wessely [34]stating that “Incorrect decision-making due to incompleteinformation or insufficient resources is not the same asirrational decision-making and as such is not sufficient tocategorise someone as panicking” as well as the conclusion ofthe study ofHeliovaara, Ehtamo, Helbing, and Korhonen [23]stating that “The jams created at bottlenecks along the exitroute are often considered to be caused by irrational behavior,a state of psychological panic. However, this study shows that,under threatening conditions, clogging may be caused bycrowd members who act rationally according to simple andintuitive assumptions” are also along those lines. Further tothat, we also suggest that the research in this area needs todifferentiate between what is traditionally known as “socialoptimum” versus “individualistic optimum” in scenarioswhere humans interact with one another in their decision-making and particularly those in which they compete for lim-ited resources (which is the case in situations of emergencywith the resources being the limited capacity for escape)[35]. In such systems, these two types of optimums often donot coincide with each other. What is optimum course ofaction from an individual decision-making perspective maynot necessarily be the optimum behaviour from a systemperspective. We suggest that this is another dimension thatneeds to be considered in conversations on this topic and inmoving towards more operational definitions for rationality.

The plots shown in Figures 3 and 4 demonstrate that,similar to the term panic, the use of the term irrationality instudies of evacuation is increasing according to the quotescollected in this work. These figures, compared to Figures1 and 2, demonstrate that there were lesser numbers ofmentions of the term irrationality compared to that of panic,according to the references that we reviewed. However, thereis a relatively higher percentage of the quotes that do not sup-port the theory of collective irrationality in escape scenarioscompared to the nearly even split that was identified on thetermpanic (the column charts in the middle). In other words,irrationality appears to be a less popular and less commonterm in the studies that we surveyed in this review and iscited much less frequently in modelling studies especiallycompared to the term panic which appears to be morepervasive. We only had a handful of quotes that supportedthe theory of irrationality, whereas we extracted a relativelyconsiderable number of quotes, 26 quotes, challenging this

idea, and those quotes split evenly between the social andphysical science studies according to Figure 3.

5. Quotes on the Term ‘Herding’

The original quotes on the term herding have been listed inTable 7 inAppendix. In addition to the analysis on the quotesthat have mentioned this term, a detailed analysis was con-ducted on empirical studies about the herding assumptionin evacuations. Figure 5 provides a visual illustration of thefrequency of the comments on the term herding based onthe total set of comments, the discipline of their origin andthe type of their study of origin. And Figure 6 provides theoutcome of a temporal analysis on these comments based onthe year of publication for their study of origin.

The most common theme across the set of quotes that weanalysed was related to the definition of the term herding inevacuation. According to these quotes, herding in evacuationrefers to an increased tendency to follow the crowd, or morespecifically to imitate the action of the majority [36, 37].Thistheme was repeated in 15 quotes out of 72 quotes that wereidentified on this term (comment #18 in Table 3). Unlike theset of quotes on the term panic and irrationality that didnot provide any consensus in terms of the definition andrather added to the mixture on the definition of these terms,the quotes on herding indicated that the majority of studiesperceive this term in a roughly similar way. This is of coursebeside the point of how accurate or suitable this term is forapplication in evacuation research which is a matter we willdiscuss below. It merely reflects and describes the currentstate of the literature and the dominant view on how this termis used and what it refers to.

Another common theme among the quotes we obtainedwas the use of imbalanced utilisation of exits observed incrowd escape scenarios (regardless of how likely that is tooccur) as evidence for herding [17, 38, 39]. This constitutesthe reduced comment #20 in Table 3 that was repeated 11times across all the quotes. The statements reflected by thisreduced comment basically assumed that if the crowd showsan imbalance in the utilisation of exits in spaces wherethere are multiple exit options, then that can be regardedas evidence that individuals within the crowd tend to copythe action of majority. However, whether this imbalanceduse of exit capacities stems from an inherent tendency forcopying the action of the majority (that individuals made aconscious decision to follow the crowd) or is attributable toother reasons is a matter of debate which will be discussed inmore detail in the following sections [40–42].

A considerable body of studies that we reviewed providedcomments that indicate herd behaviour, as a feature of escapepanic, is a common form of behaviour in evacuations andthus it should be a common assumption for numericalmodelling (i.e., numerical models need to produce herdingeffect in order to be deemed realistic) [18, 43–46]. These arecollectively reflected in reduced comments #1, 2, 4, and 6in Table 3. While we leave examination of the validity ofthis assumption to our discussion on empirical studies, weonly mention here that as opposed to these abundant set of


Table3:Re

ducedcommentson

theterm

herdingandtheirfrequ

ency

amon

gtheo

riginalqu

otes.

No.

Com

ment

Frq.

Disc

iplin

eStud

ytype

Soc.

Phys.

Bio.

Mod

.Em

p.Test.

Con

c.1

Herding

isafeature

ofpanicb

ehaviour

101

72

73

12

Herding

iscommon

evacuatio

nbehaviou

r10

17

27

30

3Herding

isno

tcom

mon

evacuatio

nbehaviou

r3

11

10

30

4Herding

iscommon

mod

elingassumption

60

60

51

05

Pure

herdingisno

tanaccuratemod

elingassumption

10

10

01

06

Prod

ucingherdingeffectsisac

ommon

criterio

nforv

erify

ingsim

ulationmod

els

10

10

10

07

Herding

canbe

beneficialtoevacuatio

neffi

ciency

10

10

10

08

Thee

ffectof

herdingon

evacuatio

neffi

ciency

isun

clear

30

30

12

09

Herding

isdetrim

entaltoevacuatio

neffi

ciency

50

41

41

010

Mixture

ofherdingandindividu

alisticbehavior

isbeneficialtoevacuatio

ns1

00

10

10

11Stressincreasesh

erding

tend

ency

30

30

12

012

Stressdo

esno

tincreaseimitatio

ntend

ency

10

11

01

013

Herding

tend

ency

ismod

erated

bystr

esslevel

10

10

01

014

Herding

tend

ency

ismod

erated

bythec

rowd

ednesslevel

30

30

03

015

Herding

tend

ency

ismod

erated

bythelevelof

uncertainty

80

71

44

016

Herding

results

from

follo

wingneighb

ours

10

10

01

017

Herding

isno

tthe

samea

simitatio

n2

11

00

20

18Herding

means

imitatin

g/follo

wingothers/m

ajority

150

123

96

019

Herding

isob

servablein

movem

entinitia

tion

10

10

01

020

Imbalanced

useo

fexitsisevidence

forh

erding

110

74

56

021

Herding

theory

inevacuatio

nhasb

eeninflu

encedby

anim

almod

elso

fbehaviour

70

16

16

022

Herding

tend

ency

shou

ldbe

considered

inconjun

ctionwith

individu

aldifferences

20

20

02

023

Herding

theory

isin

need

ofem

piric

altesting

10

01

01

0“Frq.”indicatesfrequency.

“Soc.”,

“Phys.”,and

“Bio.”,

respectiv

ely,indicatesocia

lscie

nces,physicalsciences,and

biologica

lscie

nces.

“Mod


onc.”


piric

altesting,and

conceptualisa

tion.


Cont. H.Supp. H.

Soc.Phys.Bio.

Mod.Emp. Test.Conc.

Soc.Phys.Bio.

Mod.Emp. Test.Conc.

Cont. H.Supp. H.0

10

20

30

40

50

Freq

uenc

y

Figure 5: Visualising the frequency of quotes on the term herding that convey support for the theory versus those that challenge it. Thepie charts on the left show the frequency of the supporting comments across the disciplines (on the top) and across the study types (in thebottom). Similarly, the pie charts on the right show the frequency of the contradicting comments again across the disciplines (on the top) andacross the study types (in the bottom). The column chart in the middle compares the frequency of these comments in total regardless of thediscipline or type of the study from which the comments were extracted.

comments, we had quotes that provided a different view anddisregarded the assumption that people show herd mentalityin escape situations [47] in addition to quotes from studiesthat recognise that unless people face substantial amount ofuncertainty in their surroundings, they will not be likely totake imitative actions [48].

A number of quotes that we extracted considered howherding tendencies influences efficiency of collective crowdegress. These quotes ranged from suggesting that herdingbehaviour is a detriment to efficient evacuations [37, 49] tothose that believe this effect is still unestablished [39, 40, 50]and that there may be scenarios where herding tendenciesare beneficial to an escaping crowd [18]. The subset of thesequotes that have not been derived from any simulatingtesting and are more of a speculative nature did not madeit clear which aspect of evacuation decision-making theyrefer to when connecting herding to the escape efficiency.This is basically a distinction that has not thus far beencommon in the literature. In line with this question, thephenomenon of mixed strategy (i.e., mixture of herding andindividualistic behaviour) has been investigated by severalnumerical studies. A number of those findings reflect on thefindings of such studies. These studies have also contributeda mixture of evidence to the literature with some suggestingthat a crowd can benefit frommixed strategies [19] and somesuggesting that any percentage of herding strategy within thecrowd has a negative impact on the evacuation efficiency[51].

The plots in Figure 5 suggest that unlike panic andirrationality, the herding terminology is a much better

accepted term in the crowd dynamics literature. We foundmany quotes that support this theory and this is far morecommon among the modelling studies published in thephysical science domain. However, the temporal analysis inFigure 6 reveals that firstly, the number of quotes on theterm herding shows a surge in the more recent publicationsand secondly, those that contradict or challenge the herdingtheory (or the terminology) have only emergedwithin the lastfive years and that could be attributable to the rapid increasein the empirical studies within that period many of whichobserved evidence that did not support this theory [41, 48, 52]

6. Experimental Findings on ‘Herding’

Unlike the terms of panic and irrationality for which a lackof clear definition was one of the most noticeable aspectsof our review, the term herding has a clearer, althoughlargely implicit, definition in the literature. The majorityof the quotes indicated that this term is used to describeimitation behaviour or the act of following others. Whetherthe ‘following’ specifically means copying the action of the‘majority’ was less clear.Nevertheless, given this higher clarityof meaning, the hypothesis of herding behaviour (or as weprefer to say, the role of social influence) has been moreoperationalizable and this has allowed the hypothesis to beempirically tested in various forms by considerable numberof studies mostly published within the last five years. Here,we comprehensively review these studies and their findings toseewhatwe currently know about this behavioural theory.We


1993

-1997

1998

-2002

2003

-2007

2008

-2012

2013

-2018

0

10

20

30

40

50

60

No.

of q

uote

s

Soc.Phys.Bio.

1993

-1997

1998

-2002

2003

-2007

2008

-2012

2013

-2018

0

10

20

30

40

No.

of q

uote

s

Cont. H.Supp. H.

1993

-1997

1998

-2002

2003

-2007

2008

-2012

2013

-2018

0

5

10

15

20

25

No.

of q

uote

s

Figure 6: Visualising temporal analyses on quotes that include the term herding.The column chart on the top represents the total number ofquotes and the ones in the bottom splits the frequency based on whether the quotes support or contradict the theory (chart on the left) andbased on the study discipline (chart on the right). To account for the fact that the last time interval includes 6 years as opposed to the rest ofthe time intervals that include 5 years, the numbers associated with the last interval have been scaled down by a factor of 5/6. The very fewstudies covered by this review and published prior to 1993 or in 2019 we accommodated in the first and last intervals, respectively.

also discuss the variety of terminologies that have been usedto describe this phenomenon along with their implications.

The set of studies that we reviewed often identify asexperiments on peer effect, social influence or neighboureffect in evacuations [53–56] and some directly frame thestudy as an investigation of herding behaviour [50, 57]. Thissection provides a comprehensive review of these studies.In total, 24 studies were identified on this topic which haveused empirical data of some form. The characteristics ofthese studies were analysed and subsequently summarised inTable 8 in Appendix. This table shows four main aspects ordimensions of each of these studies: (i) what aspect of theevacuation behaviour was investigated in relation to the peereffect, (ii) what method they used for their data collection(this could be virtual-reality, real crowds, or nonhumancrowd experiments), (iii) did the study find evidence ofherding effect (which according to the majority of the bodyof studies, refers to imitative behaviour), and (iv) what isthe main interesting aspect of their findings (this part isprovided as a short comment alongside each reference). Thisanalysis is the first to officially recognise that studies anddiscussions on herding in evacuation should be performed inrelation to specific aspects of evacuee’s decisions as opposedto discussing the topic in broad terms such as whetherpeople generally show an amplified tendency towards mass

behaviour (in all aspects of their decision-making). We haveidentified and reported the specific aspect of the decision-making that has been investigated in connection with peerinfluence for each of the studies listed in Table 8 .

6.1. Definitions and Alternative Terminologies for Herding. Asmentioned previously, the problem has been framed using arange of terminologies such as imitation [49], allelomimeticbehaviour, or allomimetic behaviour [46] (defined as arange of activities in which the performance of a behaviourincreases the probability of that behaviour being performedby other nearby animals), social influence [54, 55], peerbehaviour effect [53], neighbour behaviour effect [56], follow-the-crowd behaviour [48], and of course, herding or herd-type behaviour [41, 50, 52, 57, 58]. The phenomenon is alsoreferred to by a substantial body of studies as “symmetrybreaking” [42, 59–62]. Froma linguistic perspective, however,the term does not exactly equate imitation. According to theLongman Dictionary [63], the verb “herd” means “to bringpeople together in a large group” or “to make animals movetogether in a group”. However, as shown in the previoussection, the term is used almost as a substitute for “imitation”in the crowd dynamics literature.

As a pioneer study in the field of crowddynamicsHelbing,Farkas, and Vicsek [19] discussed the phenomenon and


introduced it to numerical simulations. In their conceptu-alisations “pure herding behaviour implies that the entirecrowd will eventually move into the same and probablyblocked direction, so that available exits are not efficientlyused”. These numerical testings were conducted in relationto a simulated room with two exits. Therefore, we assumethat the term herding in its original form was specificallyused in relation to exit choice behaviour. And this is infact a common characteristic of the main body of studiesthat have so far investigated the herding assumption usingempirical methods. They predominantly interpret herding inthe context of exit choice making. However, the literaturehas been increasingly recognising the role of social influencein other aspects of evacuation decision-making and a fewstudies have looked into this problem in connection withreaction responses of evacuees [55, 58, 64] and exit choiceadaptation (or exit choice changing) behaviour [65, 66]of evacuees. Hence, in our analysis of the 24 empiricalstudies on this topic, we have categorised each item intoone (or occasionally two) of these three categories: exit(direction) choice, exit (direction) choice changing, andreaction times. We also identified four general experimentalmethods that have been adopted to study this topic: humancrowd (laboratory or evacuation drill) experiments, virtual-reality experiments, experiments with groups of ants, andexperiments with groups of mice (as analogical experimentsof human crowds).

In the following subsections, we first investigate theorigins of the term herding in crowd dynamics and reviewthe first experiments (predominantly based on social insects)which referred to this notion as the ‘symmetry breaking’ phe-nomenon. We subsequently review the findings of empiricalstudies that investigated the role of the social influence inrelation to each of the three behavioural sublayers that iden-tified earlier. We then discuss two questions in subsectionsthat follow: (1) can observations of herding with social insectsor animals be reliably extrapolated to humans and (2) is theterm herding itself a suitable terminology to be used in crowddynamics.

6.2. Herding and Symmetry Breaking. The first attempt toempirically test the herding assumption in the context ofcrowd escape dates back to 2005 (five years after the pub-lication of the pioneer paper in Nature [19]) where a studypublished by American Naturalist reported on observing“symmetry breaking” effects in experiments with groups ofants [62]. According to the authors, “The phenomenon ofherding is a very general feature of the collective behaviorof many species in panic conditions, including humans” andthis statement constitutes themain premise of their study.Theauthors observed in this work that groups of ants confinedin a chamber show an elevated level of imbalanced exitutilisation when repelled by an aversive stimulus (a certaindose of repellent chemical) and inferred that as a sign thatherding phenomenon exists in collective escape scenariosand that the behaviour is shared across a range of speciesincluding humans: “Our experimental results, combinedwith theoretical models, suggest that some features of thecollective behavior of humans and ants can be quite similar

when escaping under panic.” Another statement that theauthors have made in their study is that “It has been predictedtheoretically that panic induced herding in individuals con-fined to a room can produce a nonsymmetrical use of twoidentical exit doors”. In evaluating this statement, we argueon a major factor that seems to have been neglected and thatis the differentiation between exogenous and endogenousmodelling assumptions in numerical simulation methods.The assumption of herding in Helbing, Farkas, and Vicsek[19] was clearly an exogenous assumption meaning that theauthors formulated and imposed this assumption in theformulation of their numerical model. Clearly, when oneformulates a certain type of phenomenon in the form ofmathematical models and implements that model, observingthat phenomenon (formulated exogenously) cannot reason-ably be regarded as a proof of that phenomenon. We believethat this is a distinction that in a number of cases like this theliterature has failed tomakewhen concluding fromnumericalstudies in this field in general. The conclusion from thisstudy has also been cited as an evidence that greater levelsof stress and urgency make humans to be more inclinedtowards imitating the majority’s action in an emergencyescape context.

The assumption and terminology of symmetry break-ing were subsequently followed up by further studies thatadopted the ant experiment technique and often made varia-tions to the type of the aversive stimulus [61]. This includesthe study of Chung and Lin [59] where using controlledheat-induced aversive stimulus, they observed that the degreeof asymmetry increased linearly with the temperature, andalso the study of Li, Huan, Roehner, Xu, Zeng, Di, andHan [60] who investigated the effect of density on theextent of symmetry breaking and observed that the degreeof asymmetry increased then decreased by ants’ density. Themost recent study of this kind has shown that symmetrybreaking is associated with the difference in the width ofexits in proportional ways, thereby concluding that there are,in fact, some patterns of symmetry in symmetry breakingphenomenon in ant groups [42].

6.3. Herding in Movement Initiation. Laboratory crowdexperiments in virtual and real(istic) environments haveincreasingly furthered the knowledge on the role of socialinfluence within the recent years [67]. The problem ofpremovement time in particular has received attention inthis context. According to Bode and Codling [68], “Socialinfluence occurs when individuals respond to the behaviourof others and it is an important factor that needs to beconsidered in research on premovement times in evacua-tions”. The virtual-reality experiments of Kinateder, Muller,Jost, Muhlberger, and Pauli [55] and Van den Berg, vanNes, and Hoogendoorn [58] have both provided evidenceon the significant role of peer behaviour effect on reactionto threat (or movement initiation) responses of evacuees.They have shown that the presence of passive virtual agentmade subjects delay their movement reaction, the morepeople someone sees leaving, the more inclined this personis to leave, and that seeing people leave has more impact


than seeing people stay. The two experiments have beenconducted at different levels of virtual crowd density and theycollectively suggested that evacuees’ reaction to an emergencysignal is impacted by their neighbours’ behaviour and thedirection of influence is towards taking imitative actions,regardless of whether or not the crowd in dense. In relationto the premovement time response, we only know of onestudy in nonvirtual experimental setting and that is thestudy of Nilsson and Johansson [64] who utilised the datafrom an evacuation drill in a cinema. According to Galea,Deere, Hopkin, and Xie [69], “a subset of data from thesetrials was later analysed to explore the impact of socialinfluence of close neighbours on response time” and “theauthors did report that response time for an individual wasrelated to that of a neighbour, so that participants acted morelike their neighbours than to others”. They concluded fromtheir analysis that social influence is an important factor inreaction time, especiallywhen cues about dangers are unclear,and that social influence (on reaction time) increases withdecreasing distance between visitors.

In terms of the influence of imitation in movementinitiation on evacuation efficiency, we do not know of anystudy that has empirically tested this question, but a recentnumerical study has shown that lesser variability in reactiontimes (which could be achieved when individuals tend toinitiate their movement as soon as their peers/neighbours doso) shortens the duration of the evacuation [70]. And thishas been shown to be the case across a variety of densitylevels (up to extreme densities). This suggests that herding inmovement initiation could be a beneficial form of behaviour(although we should mention that numerical evidence tothe contrary of this finding also exists [71] suggesting thata “staged” evacuation strategy (or waiting strategy) could bemore efficient than instant collective response).

6.4. Herding in Exit Choice. As mentioned earlier, a signifi-cant portion of the empirical knowledge on the role of socialinfluence has been obtained from experiments that inves-tigated exit choice behaviour. The experiments reported byBode and Codling [52] adopted a simplified form of virtual-reality setting in which the subjects have a top-down viewof a two-dimensional computer-simulated crowd evacuationscene and control and navigate their simulated agent usingmouse clicks while interacting with simulated agents. Thesetting of this study simulates relatively dense crowd escapescenarios. No distinct pattern of herding behaviour wasobserved in this study. Experiments of direction/exit choicein three-dimensional forms of virtual-reality have beenreported in [54, 55, 72, 73] where the experimental settingoften simulated a not-heavily crowded scene. As indicated bythe analysis in Table 8 , these studies have generally foundevidence for social influence in the direction of imitation. Thevirtual-reality exit choice experiments reported by Lovreglio,Fonzone, dell’Olio, and Borri [50] have been framed andanalysed in the form of discrete choice experiments andrepresent relatively dense crowds. Using mixed logit models,the authors estimated the relative importance of differentfactors on exit choice. Their findings suggest that on average

social influence, measured as the number of people at exits,reduces the likelihood of exits being selected. Therefore, thisstudy suggests that social influence has an effect, but thatthe effect is the opposite to what is commonly proposedunder the herding assumption. The findings in this workalso qualitatively match those reported in [74], derived froman independent discrete choice survey, which again doesnot support the herding assumption. Another aspect thatis shared between these two studies and also the virtual-reality studies of Kinateder, Comunale, and Warren [56]and Bode, Wagoum, and Codling [75] is that they haveall produced evidence that suggest exit choice making is amultiattribute trade-off (between time-dependant and time-independent factors [75]). While peer behaviour appears tohave significant effect on evacuees’ exit decision, it is alsotraded off with a range of other factors.

These findings have demonstrated that one cannotassume that peer behaviour is the sole determinant of exitchoices and that is one of the main reasons we suggest thatthe term herdingmay not be themost suitable terminology tobe used in this context. First of all, it indicates, by implication,that the influence of observing peer behaviour is always to thedirection of imitation (whereas, sometimes the opposite is thecase) and secondly, it dismisses the role of other contributingfactors that compete with peer behaviour effect. It implies adecision-making mechanism that is predominantly governedby social influence. The overall message of the virtual-realityexperiments has been that in not-heavily crowded scenessocial influence acts to the direction of imitation and inheavily crowded scenarios the direction of influence largelyreverses. But in all those cases, one also needs to take intoaccount the effect of other contributing attributes to thedecision-making (other than social influence) as well asthe role of individual differences in perceiving the socialinfluence [76].

Recent experiments conducted using crowds of volun-teers, particularly those from which individual-level exitchoice observations were extracted [48], generally confirmthe findings of the virtual-reality experiments discussedabove. Particularly, the presence of multiattribute trade-offbetween a set of factors that include peer influence appearsto be a recurring theme in all those studies [77]. In highlydense laboratory crowd experiments, the dominant patternof exit choice behaviour has been avoiding the majority[65]. However, Haghani and Sarvi [48] have shown thatwhen attribute ambiguity is introduced, the peer behaviourcan act at a positive direction (meaning people tend toperceive direction chosen by majority more positively or atleast, less negatively in relation to the alternatives for whichattribute ambiguity exists). Therefore, it has been suggestedthat the influence of peer behaviour in evacuation contexts ismoderated by the extent of decision uncertainty that evacueesface.

In a recent study, Haghani and Sarvi [41] tested the effectof urgency level as well as the density level on the perceptionof peer behaviour and the results overall suggested that noneof these factors lead to an increased tendency to imitate oth-ers. Under higher levels of simulated urgency or when facedwith a larger total number of people, decision-makers became


actually less likely to follow the direction chosen by themajority. In terms of how imitation in exit choices influencesegress efficiency, we currently only can resort to the evidencefrom numerical simulations that suggest any elevated degreeof imitation in exit choice making negatively influences totalevacuation times. The suggestion from numerical studies isthat, when familiar with the location of exits, a crowd ofevacuee is best off avoiding a follow-the-majority strategy[49].

6.5. Herding in Exit Choice Adaptation. The empirical evi-dence on the role of peer effect in how evacuees change/adapttheir decisions is very sparse.The topic of decision adaptation[78–80] within the general framework of evacuee’s decision-making [81] is in general highly underrepresented in thecrowd dynamics literature. In particular, when contrastedwith the growing body of studies that have experimentedexit choice behaviour within the recent years [56, 75–77,80, 82–85] very little attention has relatively been paid tothe mechanisms of exit choice changing. Proportionately,much less is known about the influence of peer behaviour onthis aspect of evacuee’s behaviour compared to the influenceon exit choice. Recent studies that have experimented thisproblem, however, have shown that, in crowded evacuationscenarios (where queues form at exits), observing otherpeople changing their exit decisions is a trigger for theobserver to change the initial decision and imitate that action[65, 66]. It has been shown in these experiments that onceone evacuee decides to leave a queue formed at an exit andjoin another queue at another exit, it increases the likelihoodof decision changing by others followed by a burst of decisionchanges. This phenomenon, however, even though it indi-cates imitation, is not precisely consistent with a definitionof herding as “following the majority”. It is consistent with adefinition of herding as “imitating others” but “others” in thiscase are often the minority. In such scenarios, at any pointin time, there are more people not changing their decisionscompared to the number of individuals who decide to changetheir initial choice. Numerical testing in a recent study [86]has also been shown that certain degrees of imitation in exitchoice making enhances the efficiency of crowd evacuationsfrom a system perspective.

6.6. Herding and Extrapolation of Behaviour from SocialInsects and Animals to Humans. The findings of the exper-iment reported by Haghani and Sarvi [41], as outlined earlier,may be regarded as evidence opposite the symmetry break-ing.The experiment showed that as urgency increases, peopleshow even less tendency to follow the direction chosen bymore people.The stark contrast between this experiment andthose of the symmetry breaking experiments with ants couldbe worthy of note. The symmetry breaking phenomenonhas been proven with ants through several independentexperiments. However, recent evidence is overwhelminglysuggesting that the phenomenon does not seem to be repli-cable when tested with humans. This might be only one ofthe areas where the escape behaviour of insects and humansdiffer fundamentally and thereby, generalisation across thetwo should be avoided [87].

An implication of identifying such inconsistent obser-vations between collective escape behaviour of insects andhumans may be that, wherever possible, behavioural exper-imentation in this domain should take place with humans asopposed to alternative animals/insects as proxies for humans.In some research the notion can arise that findings fromresearch using social insects can be extrapolated directly toemergency evacuations involving humans. However, thereare fundamental differences between species that go beyondobvious physical distinguishing factors. For example, thegenetic make-up of ant colonies is largely homogeneouswhich is likely to affect the trade-off between individualsurvival and survival of other colony members. This couldexplain why entire ant colonies reenter previously evacuatednests in an attempt to save their brood (D. Parisi, personalcommunication), behaviour that is unlikely to occur at thisscale in humans.

An argument in response to our proposition is thatsuch experiments are often conducted to help us repli-cate the sense of real danger which cannot be possiblyconsidered in experiments with human subjects. It should,however, be noted that in many cases, proxies for life-threating dangers, such as creating the sense of urgency usingmonetary incentives, could be used within the frameworksof ethical experimentation and without imposing any realdanger on participants. This possibility could be taken intoconsideration as offering a trade-off between using a proxyurgency-inducing treatment with real humans (an acceptinga certain level of contextual approximation) as opposed tousing real urgency-inducing stimuli with animals/insects(and accepting their fundamental behavioural differences asa very different kind of approximation).

6.7. Is ‘Herding’ an Accurate Terminology? Previous discus-sions in Section 5 revealed that the term herding is beingused in the literature with lesser degrees of inconsistencyin terms of the definition, compared to the terms panicand irrationality. According to the quotes that we extracted,most authors use this term as a reference to the act of(blindly/passively) following others. There are alternativeinterpretations as well, such as ‘synchronisation of actions’or ‘congregations of people’ or ‘large groups moving to thesame direction’. But these definitions are not as commonas ‘copying’ or ‘imitation’ or ‘conforming to the behaviourof the neighbours or the majority’. However, in light of theempirical findings that we reviewed in this section, here weargue that, despite this relative consistency in definition, theterm herding per se lacks accuracy in conveying the meaningthat it is meant to embody.

Firstly, herding is a term that has been originally used inrelation to animal groups. In that sense, it implicitly coveysan irrational collective unconsciousness where individualssurrender their own wisdom to the group and copy thegroup blindly (thus, by a stretch of meaning, it may implicitlyconvey the meaning of ‘acting like a group of animals’). Inthat sense, the term is indeed linked to the panic/irrationalitytheory which our review suggested to be not so well sup-ported. A change of terminology may help dissociate thisconcept from panic/irrationality. Further, the mere use of the


term herding in the scientific literature gives the indicationthat there are similarities between the escape-from-dangerresponses of humans and those of animals, thereby, justifyingexperimentation of animals’/insects’ behaviour as a proxyfor that of humans. As we discussed earlier in Section 6.5,the emerging empirical evidence has not produced muchpromising evidence for such analogies. Secondly, our reviewof empirical findings showed that people exhibit variouskinds of tendency towards copying or not copying the actionsof others in evacuation contexts. Their behaviour appears tobe rather complex. For certain aspects of their behaviour (orunder certain contextual circumstances), they show tendencyto avoid the action of the majority rather than follow. Also, insome cases, they might show imitative tendency but towardsthe action of the minority rather the majority.The literature isclearly showing that social influence on evacuation behaviourdiffers depending on the type of action (e.g., movementinitiation, direction choice, and decision changing) and also,depending on certain contextual factors (e.g., how crowdedthe space is and how familiar the occupant is with the sur-rounding environment), not tomention the role of individualdifferences in all that. Therefore, there is a great amount ofnuance involved in this phenomenon that the term herdingfails to capture. The term gives the indications that when wetalk about the social influence, we essentially mean ‘followingothers’, whereas, the term social/peer/neighbour influenceitself maintains neutrality and flexibility in that regard. Itembodies both tendencies to follow or to avoid others, as wellas tendencies to follow themajority or the minority. For thesereasons, we suggest that while the idea behind exploring therole of social influence in evacuation is legitimately valid andeven essential, the problem does not need to be formulated asa question about herding.We argue that this term comes withan unnecessary amount of predisposed connotation (partlyinherited from the panic theory) as opposed to the nuance,neutrality and flexibility that is required for describing arather complex phenomenon like this.

7. Discussion

We have adopted a literature survey approach to investigate,in an open-minded way, if preferred or dominant definitionsfor the three terms we investigate have emerged over timein the literature. While we cannot claim that our literaturesearch is completely exhaustive, we argue that the numberof publications included is sufficiently large to adequatelysupport our findings. We acknowledge that the way we haveprioritised comments on the terms we investigate withinpapers and the way we have grouped or reduced commentsand categorised supportive or unsupportive comments, aswell as the disciplines that publications belong to, is to someextent subjective.Wehope that this qualitative analysis is nev-ertheless a useful synthesis of the complete body of commentswe found which we report in full in the Appendix, Tables5–7. Given the ambiguity/inaccuracy that we found regardingthe use of these terms and the lack of empirical evidence forthem (except for “herding” which is comparatively a better-defined concept), it was not possible to perform a quantitative

meta-analysis or metasynthesis on the evidence pertaining to“panic” and “irrationality”. As the empirical base for researchinto human crowd dynamics continues to grow [6], suchmeta-analyses will become an attractive option to test thesupport for specific hypotheses by incorporating evidenceacross several studies in a similar way to what has been donein other fields of research [88]. However, we anticipate thatsuch an analysis will not be possible for the three terms wediscuss here. The unification of behavioural terminologiesand hypotheses could be a major useful step towards shapingthe literature in that direction.

Our survey of the crowd dynamics literature illustratedthat the three terms that we reviewed do not have anunequivocally accepted definition in the literature. This isparticularly the case for the terms panic and irrationality.While these terms are still used in increasing numbers ofpublications, they are also discussed controversially. And inthe case of “irrationality”, most publications are explicitlycritical of the use of this term.An additional and complicatingaspect suggested by our literature search is that the termsare used and treated differently in studies from differentbroad disciplines of research. This is particularly evident forthe term “panic” which seems accepted and used (albeit indifferent ways) in studies which we classified as belongingto the physical sciences but is mostly opposed in studies weclassified as belonging to the social sciences. Based on this,we suggest that at present, the use of the three terms “panic”,“irrationality” and “herding” in the scientific literature doesnot contribute constructively to describing, understanding oreven predicting evacuation behaviour.

A recent multidisciplinary effort to define terms fre-quently used in research on pedestrian dynamics does notinclude definitions for the terms “panic”, “irrationality”,and “herding” [89]. Instead, this glossary even includes thesuggestion that some terms, including “panic”, and “herding”that lack a clear definition or could lead tomisunderstandingsshould not be used. This is in line with what we have foundby searching the literature extensively for uses of these threeterms, as well as the suggestions of several authors in the fieldof social psychology. As Quarantelli [5] already concludedin a seminal study titled “The sociology of panic” in 2001,“There are two questions that will loom even larger in thefuture. One is why despite the research evidence, the ideaof ”panic” captures the popular imagination and continuesto be evoked by scholars of human behavior. A second basicquestion is whether there is still any scientific justification forthe continuing use of the concept in any technical sense inthe collective behavior area”. Our review suggested that theuse of these terminologies has not constructively contributedvalue to the evacuation dynamics literature and if anything,in some cases, the clear lack of definitions for (at least two of)these terms has ambiguated the research field and hamperedthe efforts of the researchers.Having reviewed the use of theseterms, for example, we were not able to identify a definitionfor the term panic that can be framed as a testable hypothesis.As a result of this issue in this research domain, assumptionshave been made that can neither be verified not rejected andcomputational prediction models have been formulated thatcannot be objectively validated.


These issues do not imply that anything loosely relatedto the three terms cannot be investigated systematically.Our detailed investigation of empirical evidence related tothe term “herding” suggests a constructive way forward.While herding is arguably a vague concept, researchershave specified concrete behavioural phenomena instead, suchas imitative behaviour, that lend themselves to scientificinvestigation via observations, experiments or models. In asimilar vein, instead of focussing on the high-level ambiguousterm “panic”, we suggest it is a legitimate question to ask“how intense levels of urgency, stress or fear influence evac-uation behaviour”, “how optimality of evacuees’ decisionscan be measured, quantified or improved”, “under whatcircumstances evacuees make more suboptimal decisions”,“how observing peer behaviour influences various aspects ofevacuee’s decisions” or “under what circumstances evacueesare more/less inclined to imitate actions of others”. Impor-tantly, framing these questions in the form of ambiguousterms, such as “panic”, “irrationality”, or “herding”, mayact as an impedance in scientifically investigating the topicsbroadly related to the terms by obfuscating an otherwiseoperationalizable set of questions. In particular, the impreciseassumptions that can accompany these terms may dissuadeor divert research from studying these phenomena at thelevel of nuance that they require. Therefore, we argue that itwould be beneficial for the progress of research in this fieldthat the questions related to the three terms discussed hereare clearly stated in terms of verifiable hypotheses and beoperationalized for empirical testing.

As an illustration for why the language that is used todescribe behavioural phenomena in this context matters andcan potentially have a significant influence on shaping anddirecting the research in this field and even managementpractices, consider the following examples. The assumptionthat phenomena related to the term panic are not testable inexperimental settings with humans has made many authorsfavour pure numerical methods over experimentation orfavour experimentation with animals or insects over exper-iments with human crowds [59–62, 90–97]. In terms ofmanagement practices, the theory could be cited in crisessituations as a reason for withholding information from thecrowd by managing authorities in order to save more lives.According to the studies that we reviewed, this is based onthe rationale that if people know about a critical situation, itmight agitate them, ultimately causing them to panic whichwill lead to irrational behaviour. In contrast to this line ofthinking, several authors like Heide [25] have argued that“Evacuation warnings should not be withheld or delayed forfear of precipitating widespread panic”. Similar importantimplications are also conveyed by the term herding. Theterm, as we showed in our detailed analysis of quotes, haslargely been used in the literature to convey imitative type ofbehaviour [49]. However, the use of this (largely animalistic)term does not make it clear whether there will be contexts oraspects of behaviour in which people do not tend to imitate.It also depicts a mechanism of decision-making in whichpeer influence is the only factor or the dominant factor whiletrivialising the role of other potential contributing factors tohuman responses.

The research on evacuation dynamics has been activelyin progress for several decades. Many scholars from a rangeof disciplines have been researching this topic and significantprogress has been made. However, we argued that, if thus far,this ample effort has not converged to any well-defined andempirically supported characterisation or a well-acceptednumerical model for panic, then it may be unlikely that suchgoal be achieved in the future. This may be an indicationthat some parts of the literature in this field may be inneed a fundamental reformulation. It warrants that someof the concepts or terminologies, including those studiedin this review, be revisited and replaced with more propersubstitutes. In conclusion, we suggest that instead of framingtheir investigation under the umbrella of the frequently used,but ambiguous terms, “panic”, “irrationality”, and “herding”,researchers could simply state the precise assumptions orhypotheses underlying their work. In doing so, a moreintegrative approach between the numerical, empirical, andsocial science studies could prove useful. Table 4 lists asummary of the conclusions that we drew based on thisreview regarding the use of each of the three terms, alongwithour recommendations.

Appendix

A.

See Table 5.

B.

See Table 6.

C.

See Table 7.

D.

See Table 8.

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper.

Acknowledgments

Alessandro Corbetta acknowledges the support of the TalentScheme (Veni) research programme, through project number16771, which is financed by the Netherlands Organization forScientific Research (NWO). E. Cristiani would like to thankthe Italian Minister of Instruction, University and Research(MIUR) to support this research with funds coming fromPRIN Project 2017 (no. 2017KKJP4X entitled “Innovativenumerical methods for evolutionary partial differential equa-tions and applications”).

Journal of Advanced Transportation 19Ta

ble4:Asummaryof

thec

onclu

sions

andther

ecom

mendatio

nsassociated

with

each

ofthethree

term

s.

Panic

Conclusio

ns

(i)Paniclacks

aformalcleard

efinitio

n(ii)P

aniclacksa

unified

well-defin

edcharacteris

ation

(iii)Panicc

anno

tbetestedas

averifiablehypo

thesis

(iv)P

anicisno

ttheoreticallywe

ll-conceived

(v)P

anicisno

tempiric

allywe

llsupp

orted

(vi)Despitelack

ofcleard

efinitio

n,theterm

panicp

ersiststo

beincreasin

glym

entio

nedin

thee

vacuationdynamics

literature,particularlyin

numericalstu

dies

(vii)

Alternativetheoriesh

aveb

eenprop

osed

bysocialscientistsc

halleng

ingthetheoryof

panic

(viii)Th

ereisa

sharpdivide

betweenho

wsocialandph

ysicalscientistssee

thep

anictheory

andits

relevanceto

disaste

rresearch

Recommendatio

ns

(i)Th

eevacuationdynamicsliteraturedo

esno

tbenefitfrom

theu

seof

theterm

panica

sitp

ushesn

umericalstu

dies

towards

unverifi

ableassumptions

andno

n-testa

blem

odelform

ulations

(ii)Th

eevacuationdynamicsliteraturedo

esno

tseem

tobenefit

from

theu

seof

theterm

panica

sitp

ushese

mpiric

alstu

dies

away

from

human

experim

entstowards

alternatives

such

asexperim

entswith

insects/anim

als

(iii)Th

equestion

ofpanicc

anbe

substituted

byop

erationalizablequ

estio

ns,suchas,how

fear

andstr

essinfl

uences

collectiveb

ehaviour

indisaste

rs

Irrationa

lity

Conclusio

ns(i)

Irratio

nalityisan

impliedno

tionin

thep

anictheory,thu

s,samec

ommentslargely

applyas

above

Recommendatio

ns

(i)Irratio

nalitydo

esno

tneedto

beassociated

with

panic(

asafeature

ofpanicb

ehaviour).Th

etwo

canbe

dissociated.Be

haviou

ralrationalitycouldbe

investigatedin

itsow

nterm

with

outthe

linkto

panic

(ii)R

ationalitycanbe

re-fr

amed

as(replacedby)o

ptim

ality

ofbehaviou

rsoitcanbe

measured/teste

d(iii)Measurin

gratio

nalityrequ

iresc

lear

pointsof

reference

(iv)R

ationalitycouldbe

measuredatbo

thcollectivea

ndindividu

allevels,

each

requ

iring

theiro

wnreferencep

oints

(v)E

xperim

entalstudies

couldgive

insig

htinto

howratio

nal(op

timal)h

uman

evacuatio

nis,

andun

derw

hat

circum

stancestheirb

ehaviour

becomes

more/lessratio

nal

(vi)Num

ericalsim

ulationmod

elsc

anfurthero

urun

derstand

ingabou

thow

wecanenhancec

ollectiveo

ptim

ality

(rationality)

inem

ergencyr

espo

nse

Herding

Conclusio

ns

(i)Em

piric

alstu

dies

doconfi

rmther

oleo

fsocialinfl

uenceinevacuatio

nbehaviou

r(ii)Th

ereisrelativec

onsensus

onthed

efinitio

nof

theterm

herding,althou

ghno

tperfectly

(iii)Herding

isan

anim

alisticandrather

sensationalterm

(iv)Th

eterm

herdingim

pliesthatthe

directionof

socialinflu

ence

isalways“

imitatio

n”(not

alwaysthe

case,

sometim

estheo

pposite

“avoidingothers”isthe

case)

(v)H

erding

impliesthatthe

directionof

socialinflu

ence

isalwaysfollowingthem

ajority

(not

alwaysthe

case,

sometim

es,followingthem

inority

isthec

ase)

(vi)Herding

impliesthatsocialinfl

uenceisthe

singled

ominantfactorindecisio

nmaking(not

alwaysthe

case,ofte

npeop

lemakea

trade-off

betweenvario

usfactors)

(vii)

Thee

mpiric

alliteratures

ofarh

assuggestedthatpeop

ledo

show

tend

ency

toim

itatewhenitcomes

toevacuatio

nmovem

entinitia

tionor

decisio

nchange

initiation.

(viii)S

omee

mpiric

alstu

dies

have

show

nop

positetendencytoherdingwhenitcomes

todirectionchoice

making

especiallyin

heavily

crow

dedsituatio

ns(ix

)Con

textualfactorssuch

asthec

rowd

inglevel,thes

tresslevelorthe

levelofenviro

nmentalfam

iliarity

have

show

nto

change

them

agnitude

anddirectionof

thes

ocialinfl

uence

Recommendatio

ns

(i)Th

eterm

socialinflu

ence

ismores

uitablethantheterm

herding.

(ii)H

erding

does

notn

eedto

beassociated

with

panic(

asafeature

ofpanicb

ehaviour).Th

equestion

ofsocial

influ

ence

canbe

legitim

ately

investigatedin

itsow

nterm

s(iii)Th

equestion

abou

tthe

roleof

socialinflu

ence

shou

ldbe

studied

inassociationwith

different

specifica

spectsof

theb

ehaviour.Th

eeffectvarie

sacrossv

arious

behaviou

ralaspects.


Table5:Orig

inalqu

otes

ontheterm

panic.

Quo

tes

Qu.Re

f.No

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/

Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

Ir.Def./Ch

a.P.

Supp

.P.

Con

t.P.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

(i)Wheneverw

e(such

aspedestr

ians)p

erceiveah

ighdensity

orim

minentd

angerinaconfi

nedspace,wetendto

bepanic,which

can

lead

tosevere

injurie

sevenin

thea

bsence

ofrealdang

ers.

(ii)M

assb

ehaviorsindu

cedby

panicu

suallycausegreatloss,even

for

human’slife

(1)

[9]

∙∙

∙∙

(i)Panicisc

ommon

occurrence

inthefaceo

fimminentd

anger

(ii)P

anicisacauseo

finjuriesin

crise

s

(i)Re

sults

show

thatmod

eratepanicreduces

thee

scapetim

e(ii)S

imulationresults

show

thatmod

eratep

anic,

meaning

thattwo

escape

strategiesa

remixed,reduces

thee

scapetim

e.(iii)In

additio

n,theresultsindicatethatmod

eratep

aniccanim

prove

thee

fficiency

ofescape

(iv)F

inding

indicatesthatp

anicin

specificcond

ition

canim

provethe

efficiency

ofescape,w

hich

also

canbe

useful

ford

esigning

evacuatio

nstr

ategies.

(2)

[9]

∙∙

∙∙

Panicc

anaff

ectevacuationeffi

ciency,

inboth

beneficialord

etrim

entalw

ays

(i)Be

causepedestr

ians

tend

torand

ommotionun

derp

anic,

the

prob

ability

ofrand

ommovingthatcancharacteriz

ethe

panicisthu

sthep

anicparameter.

(ii)W

henp=1,itindicatesthatp

edestrian

moves

inac

ompletely

rand

omstr

ategy,thatispedestr

ianremains

atan

intensep

anic

(3)

[9]

∙∙

∙

Panicism

anifeste

das

rand

om(erratic)b

ehaviour

(chaos)

Insituatio

nsof

escape

panics,ind

ividualsareg

ettin

gnervou

s,i.e.,they

tend

todevelopblindactio

nism

.Furthermore,peop

letryto

move

considerablyfaste

rthanno

rmal,etc.(o.c.)

(4)

[11]

∙∙

∙∙

(i)Panicism

anifeste

das

increased

stress(nervou

sness/fear)

(ii)P

anicismanifeste

das

imitativ

e(herd)

behaviou

r(iii)Panicism

anifeste

das

elevated

physicalcompetition

“Panic:

Peop

leflightb

ased

onas

uddensubjectiv

eor

‘infected’fear;

Peop

learem

ovingim

prud

ently

;Thec

ause

ofthismovem

entcanno

tbe

recogn

ized

byan

outsider”

(o.c.)

(5)

[11]

∙∙

∙∙

Panicc

anoccurw

ithouta

nydisting

uishablecause

(i)Upto

now,

theterminology“panic”

ishigh

lycontroversiala

ndusually

avoided.

Inthismanuscript,weu

se“fear”...

(ii)Th

ereisno

precise

accepted

defin

ition

ofpanica

lthou

ghin

the

mediausually

aspectslikes

elfish,asocialo

revencompletelyirrational

behavior

andcontagionthataff

ectslargeg

roup

sare

associated

with

thisconcept

(6)

[11]

∙∙

∙∙

∙

(i)Paniclacks

aclear

defin

ition

(ii)P

aniciscommon

medialang

uage

Inspite

ofsuch

measures,em

piric

alkn

owledgeh

asshow

nthatther

eal

dang

ercomes

notfrom

thea

ctualcause

butfrom

whatisc

alled

“unp

redictable”or

“non

-adaptive”

behavior

ofac

rowdun

derp

anic.

(7)

[10]

∙∙

∙Panicisa

causeof

injurie

sincrise

s

Itisshow

nthatthev

ariatio

nof

them

odelparametersa

llows

describ

ingdifferent

typeso

fbehaviour,from

regulartopanic.

(8)

[18]

∙∙

∙

Panicc

anbe

representedby

simple

parametersinsim

ulationmod

els

Thep

heno

menaob

served

durin

gpanicscanbe

quite

different

from

thosefou

ndin

“normal”s

ituations.N

evertheless,itisdesirableto

have

amod

elwhich

isableto

describ

ethew

holespectru

mof

possible

pedestr

ianbehaviou

rinau

nifiedway.

(9)

[18]

∙∙

∙

Panicc

anbe

representedby

simple

parametersinsim

ulationmod

els


Table5:Con

tinued.

Quo

tes

Qu.Re

f.No

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/

Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

Ir.Def./Ch

a.P.

Supp

.P.

Con

t.P.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Inpanicsitu

ations

manyc

ounter-in

tuitive

phenom

ena(

e.g.

“faster-is-slo

wer”a

nd“freezing-by-heatin

g”etc.[o.c.])canoccur.

(10) [18]

∙∙

∙∙

(i)Panicleads

toexitblockages

(ii)P

aniccanaff

ectevacuation

efficiency

Crisisc

ircum

stances

often

involvec

onsid

erableun

certa

inty,con

fusio

n,andpanic.

(11)

[98]

∙∙

∙∙

Panicisc

ommon

occurrence

inthe

face

ofim

minentd

anger

..stre

sscanendup

with

panic[o.c.]

andeven

with

aggressiv

ebehaviours

(12)

[99]

∙∙

∙∙

(i)Panicism

anifeste

das

increased

stress(nervou

sness/fear)

(ii)P

anicismanifeste

das

elevated

physicalcompetition

...little

study

hasb

eencarriedouttoexam

inethese

interactions

under

panicsitu

ationdu

eto

scarcityof

dataon

human

panic.

(13)

[100]

∙∙

∙Panictheorylacksempiric

alsupp

ort

Crow

dsafetyhasemergedas

anim

porta

ntissue

allaroun

dthew

orld

asthereh

aveb

eennu

merou

sincidentsin

which

crow

dpanich

asresultedin

injurie

sand

/ord

eath.

(14)

[100]

∙∙

∙Panicisa

causeof

injurie

sincrise

s

Theb

ulkof

theliterature

isrestr

ictedto

thes

tudy

ofno

rmal

(non

-panic)

pedestr

iandynamicso

rnormalevacuatio

nprocesses.

(15)

[100]

∙∙

∙∙

Theu

seof

term

panica

ndem

ergenciesinthisstu

dyrefertosituatio

nsin

which

individu

alsh

avelim

itedinform

ationandvisio

n(due

tohigh

crow

ddensity

andshorttim

efor

egress),andwhich

resultin

physical

competitionandpu

shingbehavior.

(16)

[100]

∙∙

∙∙

(i)Panicism

anifeste

das

elevated

physicalcompetition

In1954,Q

uarantelliwas

thefi

rstsocialscientisttofin

dthatthereisno

proofo

fthe

presence

ofpanicincaseso

fmajor

disaste

rs.

(17) [7]

∙∙


alsupp

ort

Anincreasedstr

esslevelisno

tthe

samea

spanic,

which

canbe

defin

edas

irrational,illogicalandun

controlledbehaviou

r(18) [7]

∙∙

∙∙

∙

Panicism

anifeste

das

rand

om(erratic)b

ehaviour

(chaos)

Und

erthep

anicsta

tethea

gentsc

oherec

loselyandalmostd

ono

tchange

thetargetexit.So

othera

lternativee

xitsareign

ored.

(19)

[101]

∙∙

∙∙

(i)Panicleads

toim

balanced

utilisatio

nof

exits

(ii)P

aniccanaff

ectevacuation

efficiency


Table5:Con

tinued.

Quo

tes

Qu.Re

f.No

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/

Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

Ir.Def./Ch

a.P.

Supp

.P.

Con

t.P.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Peop

leun

derp

anicareu

suallywillingto

movea

long

know

nroutes,

even

ifthismeans

they

runtowards

thefi

re,w

hich

may

lead

tomore

fatalities.

(20)

[101]

∙∙

∙∙

∙

(i)Panicleads

toim

balanced

utilisatio

nof

exits

(ii)P

aniccanaff

ectevacuation

efficiency

Empiric

aldatahave

show

nthatusually

thee

scapepanicc

ancause

morec

asualties

than

thea

ctuald

isaste

r(21)

[101]

∙∙

∙∙

Panicisa

causeof

injurie

sincrise

s

Somem

aylose

theiro

wndecisio

n-makingcapacityandtheh

erding

behavior

may

appear

forfollowingspecificind

ividual.Somem

ayacceleratethes

peed

ofmovem

entd

ueto

thep

anic.Som

emay

panic

thatcann

otchoo

sether

ight

exitor

even

lose

destinatio

n.

(22)

[16]

∙∙

∙∙

∙∙

(i)Panicism

anifeste

das

imitativ

e(herd)

behaviou

r(ii)P

anicismanifeste

das

elevated

physicalcompetition

Panic:Breakd

ownof

ordered,

coop

erativebehavior

ofindividu

alsd

ueto

anxiou

sreactions

toac

ertain

event...characteriz

edby

attempted

escape

ofmanyind

ividualsfro

mar

ealorp

erceived

threat...,w

hich

may

endup

intra

mplingor

crushing

ofpeop

lein

acrowd.

(23)

[102]

∙∙

∙∙

∙

(i)Panicism

anifeste

das

increased

stress(nervou

sness/fear)

(ii)P

anicismanifeste

das

elevated

physicalcompetition

Criticalsitu

ations

may

occurifthe

arriv

alflo

wismuchhigh

erthan

the

departu

reflo

w,especiallyifpeop

learetryingto

gettow

ards

astro

ngly

desired

goal(“acqu

isitiv

epanic”)o

raway

from

aperceived

source

ofdang

er(“escape

panic”)w

ithan

increaseddrivingforce.

(24)

[102]

∙∙

∙∙

∙Th

erearev

arious

kind

sofp

anic

Inthew

orstcase,suchbehavior

cantrigger

a“ph

antom

panic”,i.e.a

crow

ddisaste

rwith

outa

nyserio

usreason

s.Und

erextre

mec

onditio

ns(highdensities

orpanic),h

owever,coordinationmay

breakdo

wn,

giving

riseto

“freezing-by-heatin

g”or

“faster-is-slo

wer

effects”

,sto

p-and-go

waves

or“crowdturbulence”.

(25)

[102]

∙∙

∙∙

∙

(i)Th

erearev

arious

kind

sofp

anic

(ii)P

anicleadstoexitblockages

Weh

avep

ropo

sedac

onsistent

theoretical

approach

allowinga

continuo

ussw

itching

betweenseem

inglyincompatib

lekind

sofh

uman

behavior

(individu

alisticratio

nalb

ehaviorv

s.irrationalp

anicbehavior)

(26)

[103]

∙∙

∙∙

∙∙

∙

Panicc

anbe

representedby

simple

parametersinsim

ulationmod

els

One

ofthem

ostd

isastr

ousformso

fcollectiveh

uman

behaviou

risthe

kind

ofcrow

dsta

mpede

indu

cedby

panic,oft

enleadingto

fatalitiesa

speop

learec

rushed

ortra

mpled.

(27)

[19]

∙∙

∙∙

∙Panicisa

causeof

injurie

sincrise

s

Thec

haracteristicfeatures

ofescape

panicscanbe

summarized

asfollo

ws:(1)P

eoplem

oveo

rtry

tomovec

onsid

erablyfaste

r....(2)

Individu

alsstartpu

shing....(3)...passingof

abottleneck

becomes

uncoordinated.

(4)A

texits,

archingandclogging

areo

bserved.

(5)

Jamsb

uild

up.(6)

Thep

hysic

alinteractions

inthejam

med

crow

dadd

upandcausedang

erou

spressures...(7)E

scapeisfurth

erslo

wed

byfallenor

injuredpeop

leactin

gas

‘obstacles’.(8)

Peop

leshow

atendency

towards

massb

ehaviour,thatis,to

dowhato

ther

peop

ledo

(9)

Alternativeexits

areo

ftenoverlook

ed...[o

.c.]

(28)

[19]

∙∙

∙∙

∙∙

(i)Panicism

anifeste

das

increased

stress(nervou

sness/fear)

(ii)P

anicismanifeste

das

imitativ

e(herd)

behaviou

r(iii)Panicism

anifeste

das

elevated

physicalcompetition


Table5:Con

tinued.

Quo

tes

Qu.Re

f.No

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/

Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

Ir.Def./Ch

a.P.

Supp

.P.

Con

t.P.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Inthee

vent

ofan

emergency,un

necessarypanicc

anspread

rapidly

amon

gstm

etro

passengers,leading

toself-evacuatio

n.(29)

[43]

∙∙

∙

Panicisc

ommon

occurrence

inthe

face

ofim

minentd

anger

Inapanic,inform

ationspreadssorapidlythatpassengersoft

enself-evacuate.

(30)

[43]

∙∙

∙∙

Panicisc

ommon

occurrence

inthe

face

ofim

minentd

anger

Hum

anbehavior

inan

emergencyisqu

itedifferent

from

thatin

daily

lifeo

revenevacuatio

nrehearsal.Peop

lein

afire

scenea

revery

likelyto

beaff

ectedby

peop

learou

ndas

aresultof

uneasin

essa

ndpanic.Th

eywou

ldlik

etobe

closetothec

rowdandfollo

wtheroute

ofthem

ass

rather

than

theroute

madeb

ytheiro

wnjudgment.

(31)

[104

]∙

∙∙

∙∙

Panicism

anifeste

das

imitativ

e(herd)

behaviou

r

Casualtiesd

uringcrow

devacuatio

nin

manyun

expected

eventsare

closelyrelatedto

panicb

ehaviors.

(32)

[105]

∙∙

∙∙

Panicisa

causeof

injurie

sincrise

s

Thee

volutio

nof

herdingpeop

leto

panicp

eopleisinterpretedby

aspecificc

oncept

of“herding

–panicthreshold,”a

swellasitsutility

thresholdmod

el

(33)

[105]

∙∙

∙∙

Panicc

anbe

representedby

simple

parametersinsim

ulationmod

els

Alth

ough

theterm

“panic”

isac

ontro

versialtopic,inwhich

some

interviewdataandcase

studies

demon

stratethatpanicisa

very

rare

occurrence

infires...theideaof

panica

ndtheterm

continue

tobe

used

bythep

ublic

aswellasfi

reexperts

.

(34)

[105]

∙∙

∙∙

Panicisrareoccurrence

inthefaceo

fim

minentd

anger

Inmanyem

ergencies...panicd

oese

xistandindu

cestragic

catastr

ophes,which

cann

otbe

attributableto

build

ingdesig

nor

itsmanagem

ent

(35)

[105]

∙∙

∙∙

Panicisa

causeof

injurie

sincrise

s

Panickingindividu

alsw

illblockup

anexitthatthey

couldpassthrough

safelyatno

rmalwalking

speed.

(36)

[38]

∙∙

∙∙

∙Panicleads

toexitblockages

Assumingescaping

behavior

ofindividu

alsinem

ergencyisratio

nal

rather

than

outo

fpanicaccordingto

recent

finding

sinsocial

psycho

logy,w

einvestig

atetheb

ehavioralevolutio

nof

largec

rowds

from

thep

erspectiv

eof

evolutionary

gametheory

(37) [8]

∙∙

∙∙

Panictheorylacksempiric

alsupp

ort

Inpanicc

onditio

ns,ind

ividuals’

speeds

increase

aboven

ormal,

interactions

betweenperson

sbecom

ehigh

lyph

ysicalandmovem

ents

areu

ncoordinated

[o.c.].At

exits,cloggingandcollisio

nsoccur,as

well

asrainbow-like

archingstr

uctures.

(38)

[17]

∙∙

∙∙

(i)Panicleads

toexitblockages

(ii)P

anicismanifeste

das

elevated

physicalcompetition

Thismod

eldo

esno

taccou

ntforc

rushingbehaviorsa

ndthus

limits

the

interpretatio

nof

panicinthiscontext.

(39)

[106]

∙∙

∙

Panicism

anifeste

das

elevated

physicalcompetition

Whenthep

anicem

otionem

ergesinsomeone

inac

rowd,

his/her

neighb

oringindividu

alstendto

beinfected

viawhatistermed

emotionalcon

tagion

.

(40)

[107]

∙∙

∙∙

Panicism

anifeste

das

imitativ

e(herd)

behaviou

r

24 Journal of Advanced TransportationTa

ble5:Con

tinued.

Quo

tes

Qu.Re

f.No

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/

Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

Ir.Def./Ch

a.P.

Supp

.P.

Con

t.P.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Inordertointervenein

andmanagea

large-scalec

rowdin

which

individu

alsc

anmovefreelyin

thec

aseo

flarge-scalepanic,some

managerso

rguidessho

uldbe

organizedto

calm

thec

rowdmem

bers

(41)

[107]

∙∙

∙Panicc

anaff

ectevacuationeffi

ciency

With

such

amod

el,add

ition

alcharacteristicso

fhum

anbehavior

ina

disaste

revacuationscenario

couldbe

captured

such

aserratic

actio

nandpanic.

(42)

[14]

∙∙

∙∙

Panicism

anifeste

das

rand

om(erratic)b

ehaviour

(chaos)

(i)Th

e“faste

risslower”e

ffectindu

cedby

panicw

asanalyzed.

(ii)A

stateof

panicisa

ssociatedwith

high

values

ofvd

[desire

dvelocity]

i.e.,individu

alstry

tomovefastera

ndfaste

rtow

ards

thee

xit

door.

(43)

[108]

∙∙

∙∙

Panicleads

toexitblockages

Thec

ontin

uity

ofboth

curve(...)sho

wsthe

tend

ency

ofpeop

leto

follo

wthem

ajority

durin

gpanic.

(44) [1]

∙∙

∙∙

∙

Panicism

anifeste

das

imitativ

e(herd)

behaviou

r...thefl

owrateof

pedestr

iangoingoutthrou

ghan

exitdo

orof

width

Lisconsidered

alinearfun

ctionof

L[U

nder

norm

alevacuatio

ncond

ition

s(no

panic)]...un

derp

anicsituatio

n,thisisno

long

ervalid

.

(45)

[109]

∙∙

∙∙

Panicleads

toexitblockages

Song

etal.distinguish

edthec

rowdin

panics

ituations...accordingto

peop

lewho

will

(a)selectthe

closestexit,(b)b

eintotalpanic,

and(c)

follo

wthefl

owof

thec

rowdarou

ndthem

(41).Th

epercentagein

each

groupwas

90%,5%,and

5%,respectively.

(46)

[110]

∙∙

∙∙

Panicked

individu

alsm

ayhave

anegativeimpacton

otherp

eopleand,

onthec

ontra

ry,the

calm

leadership

ofcerta

inevacuees

may

inspire

orderly

movem

ento

fothers.

(47)

[105]

∙∙

∙∙

Panicc

anaff

ectevacuationeffi

ciency

Thee

motionof

thec

rowdoft

enisin

anun

reason

state.N

egative

emotions,suchas

panic,may

indu

cedisastr

ousformso

fcollective

human

behaviors,e.g

.,crushandtra

mple

(48)

[107]

∙∙

∙Panicisa

causeof

injurie

sincrise

s

Panich

asbeen

associated

with

individu

alisticrespon

sesa

ndcharacterised

by“self-p

reservationatallcosts,

by‘irratio

nal’

anim

alisticbehaviou

rinvolving

theb

reakdo

wnof

groupties...

Evidence

will

bepresentedto

show

thatthisisan

inaccurate

generalisation

(49)

[12]

∙∙

∙∙


alsupp

ort

Thereh

asbeen

aresistance

topsycho

logicalstudies

ofhu

man

actio

nin

fireb

ecause

oftheb

elief[o.c.]

thattheterm

‘panic’

provides

asufficiently

accuratedescrip

tionof

peop

le’srespo

nseto

hazardou

sevents.

Sime[o.c.]

hasp

ointed

tothee

ssentia

ldiffi

culty

associated

with

theu

seof

theterm

‘panic’,inthatithas“ruledouta

ttemptstoexam

ine

directlypeop

le’se

xperiences

ofcoping

inafi

resituatio

n”.

(50)

[12]

∙∙

∙

(i)Paniclacks

aclear

defin

ition

(ii)P

anictheory

lackse

mpiric

alsupp

ort

Woo

dhasfou

ndthatbehaviou

rduringfires

isinflu

encedby

social

rolesa

ndthatdifferent

groups

with

inthes

ampled

isplayeddistinctiv

epatte

rnso

frespo

nse.Th

iswou

ldsuggestthatevacuationisno

tarand

om,irrational‘panic’respon

seeven

thou

ghpeop

learea

cting

understre

ss.

(51)

[12]

∙∙

∙∙


alsupp

ort

Inthep

astthese

factorsh

aveb

eenconsidered

thec

lassicsituatio

nal

determ

inantsof

competitiveflighto

r‘panic’behaviou

r...Analternative

mod

elof

‘affiliativ

e’escape

behaviou

rise

xamined

inthep

resent

paper.

(52)

[15]

∙∙

∙

Socialaffi

liatio

ntheory

presentsan

alternativetothep

anictheory

Ithasb

eenargued

thatmanyo

fthe

assumptions

aboutescape

behaviou

rinthefi

reregulatio

nsanddesig

nliteraturederiv

efrom

the

notio

nthatwhenfacedby

afire

threat,p

eoplehave

atendencyto

‘panic’.

(53)

[15]

∙∙

Panicisa

very

pervasiveassumption

inmod

ellin

gliterature


Table5:Con

tinued.

Quo

tes

Qu.Re

f.No

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/

Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

Ir.Def./Ch

a.P.

Supp

.P.

Con

t.P.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

(i)Th

epanicmod

elof

escape

behaviou

rassum

esthatpeop

lethreatened

byentra

pmentw

illrevertautomaticallyto

prim

itive,h

ighly

emotional,irrationalb

ehaviour

(ii)Th

epanicandph

ysical-science

mod

elsa

reinextricablylin

ked

throughthea

nalogy

madeb

etweenpeop

leandno

n-thinking

objects

(54)

[15]

∙∙

∙∙

Panicism

anifeste

das

non-hu

manisticbehaviou

r

(i)Th

eword‘panic’

isfre

quently

used

inmediaaccoun

tsand

statementsof

survivorso

femergencyevacuatio

nsandfires,but

what

does

itreallymean,isitap

heno

menon

thatactuallyoccurs?

(ii)D

espitethed

atademon

stratingthatpanicisa

very

rare

occurrence

infires,the

idea

ofpanica

ndtheterm

continue

tobe

used

bythe

publicas

wellasfi

reexperts

(55)

[30]

∙∙

∙

(i)Panicisc

ommon

medialang

uage

(ii)P

anictheory

lackse

mpiric

alsupp

ort

(iii)Panicisa

very

pervasive

assumptionin

mod

ellin

gliterature

Therea

revario

usaccoun

tsin

theliterature

of‘m

assp

anic’,allof

which

assumep

sychologicalvulnerability,since

they

claim

that,inthec

ontext

ofthreat,the

crow

dbecomes

acon

duitforinh

erenttendenciestow

ards

dysfu

nctio

nalb

ehaviour,d

elusory

beliefsandsocialpathology.

(56)

[24]

∙∙

∙∙

Panicc

anaff

ectevacuationeffi

ciency

Theorie

sof‘panic’typically

suggestthatlosso

fbehaviouralcontrol,

andhenceselfishn

essa

nddisorder,isg

enericin

emergencies.How

ever,

review

sand

case

studies

ofem

ergenciessho

wthatcoop

erationis

relativ

elycommon

with

inandacrosscrow

ds.

(57)

[24]

∙∙

∙∙

(i)Panicisa

very

pervasive

assumptionin

mod

ellin

gliterature

(ii)P

anictheory

lackse

mpiric

alsupp

ort

(iii)So

cialaffi

liatio

ntheory

presents

analternativetothep

anictheory

Thec

oncept

of‘panic’

hasservedto

justify

ther

estrictionof

such

essentialp

ublic

inform

ation–basedon

acon

cern

thatthec

rowdmight

‘panic’.

(58)

[24]

∙∙

Panictheoryhassignificant

implications

forc

rowdmanagem

ent


ble5:Con

tinued.

Quo

tes

Qu.Re

f.No

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/

Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

Ir.Def./Ch

a.P.

Supp

.P.

Con

t.P.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Thisgeneralm

odelprovides

astro

ngbasis

onwhich

torefutethe

‘panic’

descrip

tionof

behaviou

r.Itsupp

ortsandrefin

esWoo

d’s[16]

earlier

finding

thatfirev

ictim

sdono

tbehaveinan

irrationalm

anner

(59)

[12]

∙∙

∙∙


alsupp

ort

Crow

dqu

akes

area

typicalreasonforc

rowddisaste

rs,tobe

disting

uished

from

crow

ddisaste

rsresulting

from

‘massp

anic’

or‘cr

owdcrushes....According

ly,things

cango

terriblywrong

inspite

ofno

badintentions

from

anyone.

(60)

[111]

∙∙

∙Panicisa

causeof

injurie

sincrise

s

Itiswidelybelievedthaton

eofthe

mostd

isrup

tiveconsequences

ofa

terrorist

attack...wou

ldbe

publicpanic.Indeed,thisiso

neof

the

prob

ablegoalso

fthe

terrorists.

(61)

[112]

∙∙

∙Panicisa

causeof

injurie

sincrise

s

Theresultscontradict

mosto

fthe

predictio

nsof

them

assp

anicmod

elandaddto

thed

ominanta

ffiliatio

nandno

rmativeapproaches...Th

ese

results

supp

orta

hypo

thesisaccordingto

which

(emergent)c

ollective

identitymotivates

solid

arity

with

strangers.

(62)

[113]

∙∙

∙

(i)Panictheorylackse

mpiric

alsupp

ort

(ii)S

ocialaffiliatio

ntheory

presents

analternativetothep

anictheory

Images

ofgrouppanica

ndcollectivec

haos

areu

biqu

itous

inHollywoo

dmovies,mainstre

ammediaandther

hetoric

ofpo

liticians.

But,contrary

tothesep

opular

portr

ayals,grouppanicisrelativelyrare.

Indisaste

rspeop

leareo

ftenmod

elso

fcivility

andcoop

eration.

(63)

[114]

∙∙

∙


mpiric

alsupp

ort

(ii)S

ocialaffiliatio

ntheory

presents

analternativetothep

anictheory

(iii)Panicisc

ommon

medialang

uage

(i)Ireporte

videnceshow

ingthatpanicd

idno

tcause

thed

eath

and

injury

ofnu

merou

syou

ngpeop

lepriortoac

oncert.

(ii)I

conclude

thattheoreticalmod

elso

fpanics

or“crazes”

with

inthe

literatureon

collectiveb

ehaviora

reno

tveryuseful

inexplaining

this

type

ofincident.

(64)

[115]

∙∙

∙∙


alsupp

ort

Manysocialscientistsw

ould

categoriz

ethec

rowdbehavior

describ

edaboveform

ofpanic-usually

term

edan

“acquisitivepanic”

(o.c.)o

r“craze”(o.c.).Smelserd

istinguish

esitfro

mthec

lassicpanics

ofescape,

e.g.,flightfrom

aburning

build

ing,

inthatthelatterisa

“headlon

grush

away

from

something

”whilethec

raze

isar

ush“tow

ard

something

[thep

articipants]

believe

tobe

gratify

ing.

(65)

[115]

∙∙

∙∙

Therearev

arious

kind

sofp

anic

Alth

ough

manyc

ollectiveb

ehaviortheoristsd

iscussthe

phenom

enon

,syste

maticstu

dies

ofpanica

reun

common

.Researcherscond

uctin

gsuch

studies

generally

conclude

thatpanicisa

rare

form

ofcrow

dbehaviou

r.QuarantelliandDyn

es(1972)

repo

rtthatthey

have

foun

dfewinsta

nces

ofpanica

ftery

earsof

disaste

rresearch.

(66)

[115]

∙∙

∙∙

Therearev

arious

kind

sofp

anic

Alth

ough

notincompletea

greement,writerso

npanicb

eforeMintz

hadtend

edto

emph

asizep

erceived

dang

erandmutualinfl

uence

(suggestion

,con

tagion

,mim

icry)a

sthe

keyfactorsinthed

evelopment

andspread

ofincoordinatedandno

nadaptive“panic”

behavior

(67)

[33]

∙∙

∙∙

∙

(i)Panicism

anifeste

das

increased

stress(nervou

sness/fear)

(ii)P

anicismanifeste

das

imitativ

e(herd)

behaviou

rIntensefearissho

wnno

ttobe

impo

rtant

becauseeven

inits

absence

thereo

ccurs“

behavior

analogou

stothatoccurringin

panics

(68)

[33]

∙∙

∙∙

Then

otionof

‘massp

anic’

shares

with

classic

al‘cr

owdscience’the

assumptionthatthec

rowdislessintelligent

andmoreem

otionalthan

thelon

eind

ividual(o.c.)

andhencereactions

toan

emergencywill

bedispropo

rtion

ateto

thea

ctuald

anger.

(69)

[116]

∙∙

∙∙

∙Panicisa

causeof

injurie

sincrise

s

Inthefi

eldof

masse

mergencyanddisaste

rresearch,

then

otionof

massp

anichasb

eenlargelyd

iscreditedby

thefi

ndingof

orderly

,meaning

fulm

assb

ehaviorindisaste

rs.H

owever,som

einfl

uential

practitioners,including

crow

dmod

ellersin

thefi

elds

ofengineering

anddesig

n,stilldraw

upon

then

otion.

(70)

[116]

∙∙

∙∙

∙

(i)Panicisa

very

pervasive

assumptionin

mod

ellin

gliterature

(ii)P

anictheory

lackse

mpiric

alsupp

ort


Table5:Con

tinued.

Quo

tes

Qu.Re

f.No

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/

Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

Ir.Def./Ch

a.P.

Supp

.P.

Con

t.P.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Theterm

‘panic’

isac

ommon

sensecliche.Th

eterm

isoft

enused

when

whatinfactisbeingdescrib

edissim

plyfl

ight

from

thes

ourceof

dang

er.

(71)

[116]

∙∙

∙∙

∙Paniclacks

acleard

efinitio

n

Analyseso

f9-11refer

tother

elativea

bsence

ofpanic(o.c.),the

calm

andorderliness

ofthee

vacuation(o.c.),andthefrequ

ency

ofhelping

andactsof

‘mun

dane

heroism

’amon

gststra

ngers(o.c.).

(72)

[116]

∙∙

∙∙


alsupp

ort

Shared

identityin

anem

ergencycrow

denhances

expressio

nsof

solid

arity

andredu

ces‘panic’behaviou

rand...such

ashared

identity

canarise

from

thes

haredexperie

nceof

thee

mergencyitself

(73)

[27]

∙∙

∙∙

Socialaffi

liatio

ntheory

presentsan

alternativetothep

anictheory

Itissuggestedthatthe‘massp

anic’

approach

iscorrecttosuggesta

discon

tinuity

betweeneveryday

andmasse

mergencybehaviou

r,but

wrong

inits

accoun

tofw

hatthatb

ehaviour

is.

(74)

[27]

∙∙

∙∙


alsupp

ort

[Keatin

g]po

intedoutthatp

eopled

idno

tpanic,

didno

tbecom

eanim

als,anddidno

taband

ontheirtiestoothers.Instead

they

continuedto

besocialactors...

(75)

[117]

∙∙

∙∙

Socialaffi

liatio

ntheory

presentsan

alternativetothep

anictheory

Collectives

olidarity

canmitigatefear

andnegativ

eemotions,thu

sredu

cing

ther

iskof

panic.

(76)

[118]

∙∙

Socialaffi

liatio

ntheory

presentsan

alternativetothep

anictheory

Them

assp

anicapproach

describ

esindividu

alsa

sactingin

apurely

selfish

manner.

(77)

[118]

∙∙

∙

(i)Panicism

anifeste

das

non-hu

manisticbehaviou

rIndeed,p

articipantsreferred

to‘orderly’behaviour,and

coop

eration,

even

whenthey

said

thethreato

fdeath

was

present.‘Panic’

was

thereforebeingused

asad

escriptio

nof

eventsthatwas

notcon

sistent.

(78)

[28]

∙∙

∙∙


mpiric

alsupp

ort

(ii)P

aniclacksa

cleard

efinitio

n(i)

Moreem

piric

allyoriented

studies

have

consistently

repo

rtedlittle

collectivep

anic,

aswellasa

greatd

ealofsolidarity

andpro-social

behavior

durin

gmass

emergencysituatio

ns.

(ii)M

anystu

dies

inthefi

elds

ofsociologyandsocialpsycho

logy

have

syste

maticallyqu

estio

nedthee

xiste

nceo

fmassp

anicin

disaste

rsand

masse

mergencycontexts.

(79)

[119]

∙∙

∙∙


mpiric

alsupp

ort

(ii)S

ocialaffiliatio

ntheory

presents

analternativetothep

anictheory


Table5:Con

tinued.

Quo

tes

Qu.Re

f.No

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/

Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

Ir.Def./Ch

a.P.

Supp

.P.

Con

t.P.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Defining

‘massp

anic’

inas

cientifi

cally

soun

dmannerh

aslong

been

recogn

ized

asad

ifficulttask.

(80)

[119]

∙∙

Paniclacks

acleard

efinitio

n

Panicincrow

dsisstillan

impo

rtant

theoreticalpo

stulateof

scho

lars

intereste

din

them

odelingof

collectiveb

ehavior

(81)

[119]

∙∙

(i)Panicisa

very

pervasive

assumptionin

mod

ellin

gliterature

[People]

repo

rthaving

been

inas

tateof

panictodescrib

etheirlackof

inform

ationabouta

nevent.Th

isiseven

thec

asew

henthey

infact

stayedcalm

andbehavedin

arationaland

prud

entfashion

.

(82)

[119]

∙∙

∙∙


alsupp

ort

Asusually

defin

ed,ind

ividualp

anicwou

ldinclu

dea“

reactio

ninvolvingterror,con

fusio

n,andirrationalb

ehavior,precipitatedby

athreateningsituatio

noft

eninclu

ding

physicalsymptom

sasw

ell,and

panica

sasocialph

enom

enon

isdefin

edas

simplyan

aggregateof

such

respon

ses”

(83)

[120]

∙∙

∙∙

(i)Panicism

anifeste

das

increased

stress(nervou

sness/fear)

(ii)P

anicismanifeste

das

elevated

physicalcompetition

[Aso

pposed

topanic]Ip

referthe

term

unregulatedcompetitionas

the

descrip

tivelabel.

(84)

[120]

∙∙

Paniclacks

acleard

efinitio

n

Inthisem

ergencysituatio

n,thes

urvivorsof

theb

ombing

scam

etogether

totend

totheinjured

andfin

daw

ayof

evacuatin

gsafely.

Incontrastto

portr

ayalso

fcrowds

aspanickingandactin

gselfishlyto

evacuate,researchhassho

wnthattheo

pposite

occurred.

(85)

[121]

∙∙

∙∙


alsupp

ort

Thereisg

oodreason

tothinkthattheb

ehaviour

ofhu

man

crow

dsis

quite

similartothesea

nimalgroups

andthatstu

dyinghu

mansm

ight

helpelu

cidatetheo

riginso

fcrowdpanica

ndotherd

angerous

insta

bilitiesthatcan

lead

toinjury

orlossof

life.

(86)

[122]

∙∙

∙

(i)Panicism

anifeste

das

non-hu

manisticbehaviou

r(ii)P

anicisacauseo

finjuriesin

crise

sWhilemassp

anic(and

/orv

iolence)

andself-preservatio

nareo

ften

assumed

tobe

then

aturalrespon

seto

physicaldang

erandperceived

entra

pment,theliterature

indicatesthatexpressions

ofmutualaid

are

common

andoft

enpredom

inate,andcollectivefl

ight

may

beso

delayedthatsurvivalisthreatened.

(87)

[123]

∙∙

∙

Panictheoryisno

tempiric

allywell

supp

orted

(i)Th

eterm

“panic”

refersto

inappropria

te(ore

xcessiv

e)fear

and/or

flight.

(ii)W

hether

defin

edas

inappropria

teor

ashigh

lyintensefear

orflight,

insta

nces

ofpanica

redifficultto

identifyin

practice

(88)

[123]

∙∙

∙∙

Panictheoryisno

tempiric

allywell

supp

orted

Rushingfore

xitsin

astr

ucturalfi

remay

betheo

nlyratio

nalcou

rseof

actio

nto

take.H

ence,the

decisio

nto

labelinstances

ofcollectivefl

ight

aspanicisa

rbitrary.

(89)

[123]

∙∙

∙∙

∙

Whatseemstobe

panicb

ehaviour,

may

beindividu

al’sbestperceived

course

ofactio

n


Table5:Con

tinued.

Quo

tes

Qu.Re

f.No

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/

Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

Ir.Def./Ch

a.P.

Supp

.P.

Con

t.P.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Stud

iesa

rerevealingseveralm

iscon

ceptions

aboutthe

typeso

frespon

sesthatemergenciese

voke

inpeop

le.For

exam

ple,an

umbero

fwidely-heldbeliefsam

ongthep

ublic

andthem

ediahave

been

show

nto

beincorrect,such

asthatlooting,massp

anic,

andselfish

behaviou

rarec

ommon

indisaste

rs,and

shou

ldbe

abando

nedin

favour

ofrealistic,proactiv

eem

ergencykn

owledge.

(90)

[124]

∙∙

∙∙


mpiric

alsupp

ort

(ii)P

aniciscommon

medialang

uage

Thereviewof

thee

xisting

research

literature,together

with

ouro

wn

studies,sup

portthev

iewthatmassp

anicisam

yth,andthatcrow

dbehaviou

rindisaste

rsandem

ergenciesism

eaning

fulratherthan

irrational;andthatsuch

behaviou

risc

haracteristicallyorderly

and

co-operativ

erather

than

disorderly

andindividu

alistic.

(91)

[125]

∙∙

∙∙

∙∙


alsupp

ort

Massp

anicissaid

tooccurw

henac

rowdhaso

nlylim

itedoppo

rtunity

fore

scapefro

mim

pend

ingdang

er.Itsup

posedlyexplains

theh

igh

numbersof

avoidablefatalities

inem

ergencyevacuatio

ns.

(92)

[31]

∙∙

Panicisa

causeof

injurie

sincrise

s

Massp

anicoccurswhenag

roup

ofperson

sfleeingfro

mim

minent

dang

erfin

dtheire

scaperouteim

pededor

blocked.Und

erthese

circum

stances

they

lose

allsense

ofjudgmenta

nddiscretio

n.Th

eybecomeim

pervious

tocommun

icationor

direction,

trampleo

vero

neanother,andfailto

seek

othere

xitsof

escape

even

ifavailable.Forthese

reason

smassp

anicrarelyoccursin

outside

disaste

rcirc

umsta

nces.

(93)

[29]

∙∙

∙∙

∙

(i)Panicism

anifeste

das

non-hu

manisticbehaviou

r(ii)P

anicleadstoim

balanced

utilisatio

nof

exits

From

arou

nd200accoun

tsof

theW

orld

TradeC

entersurvivors

publish

edin

them

edia,panicwas

seldom

mentio

nedinste

admany

emph

asized

thec

alm

andaltru

isticbehaviou

rofthe

evacuees.

(94)

[126]

∙∙


alsupp

ort

Thep

opular

imageo

fdisa

sterh

asoft

encentered

onthethemeo

fperson

alchaos.Such

anim

ageisfrequ

ently

documentedby

isolated

anecdo

tesu

sedto

provetheu

niversality

ofsuch

behavior.Th

isim

age

suggeststhatindividu

alsp

anicandthatindividu

alslosetheirconcern

foro

thers.

(95)

[25]

∙∙

∙∙

(i)Panicism

anifeste

das

rand

om(erratic)b

ehaviour

(chaos)

(ii)P

anicismanifeste

das

non-hu

manisticbehaviou

r

Theissue

ofpanicindisaste

rsisfre

quently

clou

dedby

alackof

understand

ingof

whatthe

term

means.Th

ewordisoft

envery

loosely

andincorrectly

used

todescrib

evirtu

allyanytypeof

fear,fl

ight,or

uncoordinatedactiv

ity.

(96)

[25]

∙∙

∙Paniclacks

acleard

efinitio

n

Thep

roblem

with

thep

anicmisc

onceptionisthatthep

ublic,the

media,

andeven

emergencyplannersandpu

blicoffi

cialsb

elieve

it.Be

causeof

this,

officialsm

ayhesitatetoissue

warning

sbecause

they

arec

onvinced

thattheresultin

gpanicw

illcausemored

amagethanthed

isaste

ritse

lf.(i)

Thisbeliefh

asledto

recommendatio

nsto

avoidpanicb

y(1)

providingminim

alinform

ationto

occupantsinthee

vent

ofab

uilding

firea

nd(2)c

arryingon

norm

alactiv

ities

until

thelastp

ossib

lemom

ent.

(ii)E

vacuationwarning

ssho

uldno

tbew

ithheld

ordelayedforfearo

fprecipitatin

gwidespreadpanic.

(97)

[25]

∙∙

(i)Panictheoryhassignificant

implications

forc

rowdmanagem

ent

(ii)P

aniciscommon

medialang

uage

Governm

entsandcommentators

perceive

thep

ublic

tobe

pron

eto

panicinrespon

seto

terrorist

attacks...Ev

idence

from

fivesuch

incidentssuggestthatthep

ublic

isno

tprone

topanic,althou

ghpeop

lecanchange

theirb

ehavioursa

ndattitud

esto

redu

cether

iskof

them

selvesbeingexpo

sedto

aterroristincident.

(98)

[34]

∙∙


alsupp

ort


Table5:Con

tinued.

Quo

tes

Qu.Re

f.No

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/

Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

Ir.Def./Ch

a.P.

Supp

.P.

Con

t.P.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Wes

uggestthatalthou

ghthep

ublic

may

change

theirb

ehaviourso

rattitud

es,inwaysthatm

ight

beview

edas

irrationalb

ypu

blic

authorities,...thesea

ctions

tend

tohave

aninternallogica

ndas

such

area

menableto

change.A

ssum

ptions

ofpanicm

aythereforebe

coun

terprodu

ctive.

(99)

[34]

∙∙

∙∙

Whatseemstobe

panicb

ehaviour,

may

beindividu

al’sbestperceived

course

ofactio

n

Duringan

emergencyevacuatio

n,forinstance,thep

resenceof

heightened

anxietyanddistr

essa

mon

gthee

vacueesc

ombinedwith

afear

ofdyingisno

tsuffi

cienttolabelthem

aspanicking

(100

)[34]

∙∙

∙Paniclacks

acleard

efinitio

n

Despiteconsiderableeffortb

ymanyind

ividualsfoun

din

thisarticle’s

referencelist,them

ythof

massp

anicstu

bbornlyrefusestodie.

(101)

[127]

∙∙

∙

Panicisa

very

pervasiveassumption

inmod

ellin

gliterature

Duringem

ergencies,thea

nticipationof

mass‘panic’hasb

eena

favoured

argumenttodelaywarning

thep

ublic.Suchdelays

have

contrib

uted

tosubsequent

flightb

ehaviour

andthec

rush

ofpeop

lewho

hadon

lyafew

second

sleft

toreacto

ncethe

situatio

nun

expectedlygoto

utof

hand

.

(102)

[26]

∙∙

Panictheoryhassignificant

implications

forc

rowdmanagem

ent

Perhapsthe

mostfrequ

ently

used

term

inconn

ectio

nwith

disaste

rsandcrise

sisthe

word“panic”...an

observationby

Jordan

unfortu

nately

stillistru

etoday.As

heno

ted:

“Theliterature

onpanicr

esearchis

strew

nwith

wrecked

hulkso

fatte

mptstodefin

e‘panic’.Whenthese

defin

ition

sare

placed

sideb

ysid

e.on

eisc

onfro

nted

bychaos.

(103)

[128]

∙∙

Paniclacks

acleard

efinitio

n

Panicfl

ight

was

sorarelyfoun

dthateventuallythev

eryconcepto

f“panicbehavior”was

deem

eduselessfor

firer

esearchpu

rposes

(104

)[128]

∙∙

∙Panicisa

rare

occurrence

Toconclude,collectivep

anicflightindisaste

rsissuch

ararity

thatitis

nota

major

prob

lem

andhasv

erylittle

overalln

egativec

onsequ

ences

comparedwith

otherb

adeffects.

(105)

[128]

∙∙


alsupp

ort

Whilesomec

urrent

researchersc

ontin

ueto

usethew

ord“panic”

inim

aginativew

ays(o.c.),w

epersonally

thinktheterm

shou

ldbe

droppedas

asocialscience

concept...Amajor

moveinsuch

adire

ction

wou

ldfre

esocialscientistsfrom

thea

mbiguities

andim

precision

sof

continuing

tousea

worddraw

nfro

mpo

pulard

iscou

rse.

(106

)[128]

∙∙

∙Paniclacks

acleard

efinitio

n

Instr

esss

ituations,one

aspectof

socialbehavior

thathasb

een

subjectedto

little

experim

entalinvestig

ationispanicb

ehavior...Byfar

theg

reatmajority

oftheliterature

consistso

fposth

ocim

pressio

nistic

reflections

thatcontainlittle

substantivem

aterialamenableto

syste

matic,analytic

interpretatio

n.

(107)

[129]

∙∙


alsupp

ort


Table5:Con

tinued.

Quo

tes

Qu.Re

f.No

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/

Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

Ir.Def./Ch

a.P.

Supp

.P.

Con

t.P.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Fore

thicalreason

s,ho

wever,there

isas

erious

lack

ofexperim

ental

dataregardingcrow

dpanic.Whilepanich

asrecentlybeen

studied

inanim

alexperim

entswith

micea

ndants[o.c.],thereisstillan

evident

lack

ofdataon

criticalcon

ditio

nsin

human

crow

ds.

(108)

[130]

∙∙


alsupp

ort

Mass-em

ergenciesa

revery

popu

larinthen

ews,whether

wew

atch

newso

nTV

orread

anew

spaper.Inmosto

fthese

newsw

eare

ableto

read

thatpeop

lewerefallenin

panico

ramass-panico

ccurred.

Thisisa

simple,buto

ftenused

explanationwhy

peop

ledied

insuch

situatio

ns.

Butisthatthe

truth?

(109)

[131]

∙∙

∙∙

Panicisc

ommon

medialang

uage

Severalresearchersin

thefi

eldof

engineeringor

sociologyhave

written

specialp

apers(e.g

.[3])o

rboo

ks(e.g.[4,5])a

bout

thep

heno

menon

ofpanic,buta

completed

efinitio

nof

panicc

anno

tbefoun

din

the

literature.

(110)

[131]

∙∙

∙Paniclacks

acleard

efinitio

n

Basedon

thisshorto

verviewthea

utho

rswanttopo

into

utthatthe

term

s“panic”,“sta

mpede”a

nd“crush”a

revery

lang

uage

specific,thus

oneh

asto

read

articlesinon

e’snativ

elanguagea

ndatleastinon

eforeignlang

uage

toensure,thatb

othlang

uage

specificv

iewsa

reconsidered.

(111)

[131]

∙∙

∙Paniclacks

acleard

efinitio

n

Thisandotherd

efinitio

nsareu

sedto

investigate127caseso

fmass-em

ergencies.Th

eresultsshow

,thatp

anicbehavior

incase

ofmass-em

ergenciesd

oesn

otas

often

occura

ssuggeste

d.

(112)

[131]

∙∙

∙∙


alsupp

ort

“Qu./Ref.N

o.”m

eans

Quote/Refe

rencen

umber.

“Links

toIr.”m

eans

(Theq

uote)links

Panic(P.)

toIrr

ationa

lity(Ir.).

“Links

toH.”means

(Theq

uote)links

Panic(P.)

toHerding

(H.).

“Def.C

ha.P.”means

(Theq

uote)d

efines/c

haracte

risesPa

nic.

“Sup

p.P.”

means

(Theq

uote)supports(thetheoryof)P

anic.

“Con

t.P.”

means

(Theq

uote)contra

dicts(thetheoryof)P

anic.

“Soc.Sci.”means

(Thesourceo

fthe

quote)isastu

dyin

Socia

lScie

nces.

“Phys.Sci.”

means

(Thesourceo

fthe

quote)isastu

dyin

Physica

lScie

nces.

“Bio.Sci.”means

(Thesourceo

fthe

quote)isastu

dyin

Biologica

lScie

nces.

“Mod

.”means

(Thesourceo

fthe

quote)isastu

dywith

amainfocuso

nModelling.

“Emp.Test.”m

eans

(Thesourceo

fthe

quote)isastu

dywith

amainfocuso

nEm

piric

alTesting.

“Con

c.”means

(Thesourceo

fthe

quote)isastu

dywith

amainfocuso

nCo

nceptualisa

tion.

Notethatind

ividua

lstudiescanbelong

tomultip

lecategorie

s(e.g

.multip

ledisciplin

es).


Table6:Orig

inalqu

otes

ontheterm

irrationality.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

P.Def./Ch

a.Ir.

Supp

.Ir.

Con

t.Ir.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Herew

ewanttoapplythismod

elto

asim

plee

vacuationprocessw

ithpeop

letrying

toescape

from

alarge

room

.Suchas

ituationcanlead

toap

anicwhere

individu

alsa

pparently

actirrationa

lly.

(1)

[18]

∙∙

∙∙

Irratio

nalb

ehaviour

isas

ymptom

ofpanic

They

thinkthatthetransition

betweenthe“

ratio

nal”no

rmalbehavior

andthea

pparently

“irratio

nal”panicbehaviorisc

ontro

lledby

asingle

parameter,the

“nervousness”,which

influ

encesfl

uctuationstr

engths,

desired

speeds,and

thetendencyof

herding.

(2)

[11]

∙∙

∙∙

Herding

isasig

nof

irrational

behaviou

r

Wea

spire

togive

answ

erstothefollowingspecificq

uestion

swhatisthe

impactbetweenchoo

singthee

scaperoutebasedon

familiarity

asoppo

sedto

ratio

nally

follo

wingthefi

reexits.

(3)

[10]

∙∙

∙

Choo

singfamiliar

exits

isas

ignof

irrationalb

ehaviour

Wed

ono

twanttoim

plythatind

ividualswou

ldalwaysb

ehave

irrationa

linem

ergencysituatio

ns.Ith

asbeen

observed

that,evenin

such

situatio

nsindividu

alsc

anbehave

high

lyself-controlled,

coordinated,

ratio

nal,andsocial

(4)

[103]

∙∙

∙∙

∙

Peop

lecanmaintainratio

nality

durin

gcrise

s

Recent

researches

insocialpsycho

logy

abouth

erding

effectin

emergency[o.c.]ind

icatethat,escapingbehaviorsa

mon

gindividu

als

arerationa

lactions

inste

adof

crow

dpanica

ndas

erieso

fpheno

mena

inclu

ding

herdingeffectare

theresulto

frationa

lcho

ices

inbehaviors

fore

scapingagents.

(5)

[8]

∙∙

∙∙

∙

Peop

lecanmaintainratio

nality

durin

gcrise

s

Mostm

icroscopicsim

ulationmod

els[o.c.]

inthefi

eldof

emergency

evacuatio

nup

tono

wareg

enerallybasedon

thea

ssum

ptionthatpanic

inste

adof

ratio

nalactions

indu

cesh

erding

effect.

(6)

[8]

∙∙

∙∙

Herding

isasig

nof

irrational

behaviou

r

Irrationa

lity:Ac

coun

tingforthe

idea

thatindividu

alsinacrow

dlose

ratio

naltho

ught

(7)

[99]

∙∙

∙∙

(i)Highherdingcauses

acrow

dof

high

ratio

nality(especially

inno

rmalcircum

stances)tobecomemore“vying

”inbehaviou

r.(ii)Th

ehigh-ratio

nalityc

rowdisshow

nto

spendmoree

vacuationtim

ethan

alow

-rationa

litycrow

din

emergencysituatio

ns.

(8)

[36]

∙∙

∙∙

Ratio

nalityisassociated

with

evacuatio

neffi

ciency

Person

swith

high

ratio

nalitydealwith

vario

ussituatio

nsaccordingto

theirp

recise

judgment,whileperson

soflow

ratio

nalitychoo

sestr

ategy

atrand

om.

(9)

[36]

∙∙

∙

Irratio

nalitymeans

deciding

rand

omly


Table6:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

P.Def./Ch

a.Ir.

Supp

.Ir.

Con

t.Ir.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Com

putersim

ulationresults

show

that...(2)inan

emergency

situatio

n,individu

alhyper-ratio

nalityam

ongevacuees

diminish

esevacuatio

neffi

ciency;(3)

theimitatio

neffectenh

ancesc

ooperatio

nam

ongevacuees,yetredu

cese

vacuationeffi

ciency.

(10)

[37]

∙∙

∙∙

(i)Ra

tionalityisassociated

with

evacuatio

neffi

ciency

(ii)H

erding

isdetrimentalto

evacuatio

neffi

ciency

Theu

nderlyingbehavior

couldbe

called“ir

ratio

nal”,

asallofthese

effectsdecrease

thec

hances

ofsurvivalcomparedto

norm

alpedestr

ian

behavior.

(11)

[103]

∙∙

∙∙

Ratio

nalityisassociated

with

evacuatio

neffi

ciency

Fora

lowlevelofp

anic,a

greatn

umbero

find

ividualsares

tillableto

choo

seautono

mou

slytheb

estexitb

ut,assoonas

theirstre

sslevel

increases,moreandmorep

ersons

imitateotherp

ersons

arou

ndthem

,discarding

anyratio

nalbehaviour.

(12)

[17]

∙∙

∙∙

∙∙

Herding

isasig

nof

irrational

behaviou

r

Gabrie

lTarde

(1901)(citedin

vanGinneken,1992)...suggestedthatby

merep

roximity

peop

lebecomea

crow

d,andhencesub

jectto

uncritical

imitatio

nandhenceirrationa

lbehaviour.

(13)

[132]

∙∙

∙∙

∙

Herding

isasig

nof

irrational

behaviou

r

Despitethee

vidence,an

umbero

fmyths

aboutd

isaste

rspersist

inpu

blicdiscou

rse,someo

fwhich

suggestthatcollectiveb

ehaviorin

emergenciesism

aladaptiv

e,irrationa

l,andeven

pathological.

(14)

[31]

∙∙

∙∙

∙

Irratio

nalityisno

tanaccuratetheory

fore

vacuationbehaviou

r

Theideathatthem

ajority

ofpeop

lein

such

circum

stances

area

cting

‘ratio

nally’atleastin

theiro

wnterm

scon

trasts

with

thec

onventional

escape

mod

elwhich

assumes

everyone

ispanicking

(15)

[15]

∙∙

∙∙

Irratio

nalityisno

tanaccuratetheory

fore

vacuationbehaviou

r

Overseveraldecades,stu

dies

specifically

look

ingatpanicb

ehaviour

infires

have

consistently

show

nthatno

n-adaptiv

eandirrationa

lbehaviou

rsarea

ctually

arareoccurrence

(16)

[30]

∙∙

∙∙

∙

Irratio

nalityisno

tanaccuratetheory

fore

vacuationbehaviou

r

Alth

ough

evacuees

might

beanxiou

s,andfre

quently

usethe

word

‘panic’

todescrib

etheiro

wnor

others’reactionto

events,

they

dono

tbehave

inan

irrationa

lora

ntiso

cialmanner.

(17)

[30]

∙∙

∙∙

Irratio

nalityisno

tanaccuratetheory

fore

vacuationbehaviou

r

One

impo

rtant

impactof

therejectio

nof

thec

oncept

ofpanicisthat

managem

entautho

ritiesshou

ldenvisio

ntheb

uildingoccupantsa

salliesd

uringafi

rerather

than

amasso

firrationa

lpeoplewho

need

tobe

controlled

(18)

[30]

∙∙

∙∙

Irratio

nalitytheory

hassignificant

implications

forc

rowdmanagem

ent

How

ever,m

anys

tudies

onhu

man

behaviou

rinfirea

ndcrow

ddisaste

rshave

show

edthateven

undere

xtremelycriticalcon

ditio

nspeop

ledo

notp

anicbuttheybehavedqu

iteratio

nally

helpingeach

other

(19)

[50]

∙∙

∙∙

Peop

lecanmaintainratio

nality

durin

gcrise

s

Therea

revario

usdefin

ition

sof‘panic’,ad

istinguish

ingfeatureo

fallof

them

isthec

rowd’s

supp

osed

irrationa

lity,which

islin

kedto

the

‘contagion’of

emotion.

(20)

[24]

∙∙

∙∙

Irratio

nalb

ehaviour

isas

ymptom

ofpanic


Table6:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

P.Def./Ch

a.Ir.

Supp

.Ir.

Con

t.Ir.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Tojudgea

respon

seas

irrationa

lrequiresa

frameo

freference,but

the

frameo

freference

isoft

enun

clearinam

asse

mergency.

(21)

[24]

∙∙

Measurin

gratio

nalityrequ

iresa

referencepo

int

Fleeing,fear,screamingor

otherrespo

nses

toperceiveddang

ermay

thereforebe

entirelyreason

able[rational]giventhelim

ited

inform

ation–andlim

itedchoices–

availabletopeop

lein

them

idstof

anem

ergency

(22)

[24]

∙∙

∙∙

Whatseemsirrationala

ct,m

aybe

individu

al’sbestperceivedcourse

ofactio

n

Aleadingexam

pleo

fsup

posedirrationa

lcrowdbehaviou

r‘panic’,

which

isgenerally

conceptualise

das

irrationa

lflight

inwhich

fearful

peop

lemay

endup

hurting

orkilling

them

selves

andothers.

(23)

[133]

∙∙

∙∙

Mythof

irrationa

lity:crow

dsmay

causep

eopletobehave

irrationa

llyor

toengage

inpanicirrationa

lflight.

(24)

[133]

∙∙

∙∙

∙

Irratio

nalb

ehaviour

isas

ymptom

ofpanic

RenzettiandCu

rran...claim

thatwhilepeop

lemay

copy

onea

nother

orlook

toothersforind

ications

ofho

wto

behave,thisd

oesn

otmean

thatthey

lose

theirrationa

litywhenin

acrowdor

similartypeof

collectivity.

(25)

[133]

∙∙

∙∙

Irratio

nalitytheory

hassignificant

implications

forc

rowdmanagem

ent

(i)Cou

ch(o.c.)a

rguedthatsomec

rowds

may

appear

irrationalinthat

they

dono

tsup

porttheideas

“sup

porte

dby

thee

stablish

edinstitutio

nsof

thed

ay.”

(ii)C

ouch’sanalyticapproach

suggeststhatthec

oncept

ofirrationality

andits

coun

terpart,ratio

nality,may

have

“limitedapplicability

for

sociologicalanalysis”

.

(26)

[133]

∙∙

∙∙

Irratio

nalitytheory

hassignificant

implications

forc

rowdmanagem

ent

Inbu

ildings

peop

lechoo

sether

oute

they

know

orwhenno

tfam

iliar

with

theb

uildingtheire

xitroute

isthew

aythey

enteredtheb

uilding.

Alth

ough

itmight

notb

ethe

mosto

ptim

alroute,thisdo

esno

timply

irrationa

lityor

rand

omness....[Th

is]canbe

considered

arisk

assessment.

(27)

[134]

∙∙

∙∙


ct,m

aybe

individu


ofactio

n

Then

otionof

irrationa

lityisoft

enused

whenpeop

learen

otbehaving

inwhatisseenas

them

osteffectivew

ayto

achievea

goal,likefl

eeing

outo

fabu

ildingwhileno

tfollowingthee

mergencyexits.H

owever,the

effectiv

enesso

fbehaviour

iscomparedto

anidealw

ayof

actin

g.Itthus

depend

sonwho

ever

defin

esthee

ffectiveo

ridealway

howandwhen

thelabel“ir

ratio

nal”isused

(28)

[134]

∙∙

∙∙

(i)Ra

tionalityisassociated

with

evacuatio

neffi

ciency

(ii)M

easurin

gratio

nalityrequ

iresa

referencepo

int

Thefactisthatp

eoplein

crow

dsdo

notb

ehaveirrationa

lly,i.e.

dono

tencoun

tera

cogn

itive

shut-dow

n.Ac

tually,

thea

vailablee

vidence

supp

ortstheo

pposite:ind

ividualsbehave

ratio

nally

giventhe

inform

ationthey

have

andthey

pursue

goalse

ffectively

(29)

[134]

∙∙

∙

(i)Irratio

nalitytheory

hassignificant

implications

forc

rowdmanagem

ent

(ii)M

easurin

gratio

nalityrequ

iresa

referencepo

int


Table6:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

P.Def./Ch

a.Ir.

Supp

.Ir.

Con

t.Ir.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Panich

asbeen

associated

with

individu

alisticrespon

sesa

ndcharacterised

by“self-p

reservationatallcosts,

by‘irratio

nal’

anim

alisticbehaviou

rinvolving

theb

reakdo

wnof

groupties(i.e.

‘non

-social’behaviou

r:igno

ringof

groupmem

bers,or‘antisocial’

behaviou

r:kicking,tra

mpling)’”[o.c.]...thisisan

inaccurate

generalisation;

however,thistypeof

descrip

tionhasimplications

for

thew

aysinwhich

motivationto

escape

isexplained.

(30)

[12]

∙∙

∙∙

Irratio

nalitytheory

hassignificant

implications

forc

rowdmanagem

ent

Mintzsuggestedthatineffectualescape

inan

evacuatin

gcrow

disdu

eto

individu

alcalculationof

costs

andbenefits,rather

than

toa

contagious

outburstof

massirrationa

lity,as

assumed

bythee

arlymass

panicm

odels.

(31)

[113]

∙∙

∙

(i)Whatseemsirrationalact,m

aybe

individu


ofactio

n(ii)Irrationalb

ehaviour

isas

ymptom

ofpanic

Thes

everalsociologicalandsocialpsycho

logicaltheorieso

fcollective

behavior

which

consider

panic...they

makev

erydifferent

assumptions

aboutthe

processp

rodu

cing

thec

ompetition,

vario

uslyattributin

gitto

irrationa

lbehaviorp

rodu

cedby

fear

andsocialcontagion

(32)

[115]

∙∙

∙∙

Irratio

nalb

ehaviour

isas

ymptom

ofpanic

Theind

ividualisn

olessratio

nalorm

oralin

thep

anicthan

inany

othersitu

ation.

Heisa

lwaysinpu

rsuito

fhisow

ninterests

andactson

theb

asisof

hisc

urrent

estim

ates

ofwhere

theselie.

(33)

[33]

∙∙

∙∙

∙


ct,m

aybe

individu


ofactio

nTh

econ

cept

ofpanicisv

ague

anddeciding

whatisrationa

land

peop

lethinkisratio

nalistric

kybu

siness

(34)

[135]

∙∙

∙∙

∙Irratio

nalitylacksa

cleard

efinitio

n

Thec

oncept

ofmassp

anicisalso

stillinflu

entia

lincrow

dmod

ellin

g(o.c.),where

itsirrationa

lista

ssum

ptions

have

implications

forthe

desig

nof

publicspaces

andevacuatio

nprocedures.

(35)

[27]

∙∙

∙∙

Irratio

nalitytheory

hassignificant

implications

forc

rowdmanagem

ent

(i)Po

pularrepresentations

ofcrow

dbehaviou

rindisaste

rsareo

ften

characterised

byirrationa

listd

iscou

rses,inparticular‘massp

anic’

despite

theirrejectio

nby

currentscientifi

cresearch

(ii)Itisc

onclu

dedthattheterm

‘panic’

isso

deeplyem

bedd

edin

popu

lard

iscou

rsethatpeop

lemay

useitevenwhenthey

have

reason

toreject

itsirrationa

listimplications.

(36)

[28]

∙∙

∙∙

∙

Irratio

nalityisno

tanaccuratetheory

fore

vacuationbehaviou

r

One

classic

alway

ofdefin

ingpanicistorefertoan

excessivea

ndgrou

ndless

feelingof

fear

which

makep

eopletake

anirrationa

land

inappropria

tecourse

ofactio

nin

anattempt

tosecure

them

selves.

(37)

[119]

∙∙

∙∙

(i)Irratio

nalb

ehaviour

isas

ymptom

ofpanic

(ii)R

ationalityisassociated

with

evacuatio

neffi

ciency


Table6:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

P.Def./Ch

a.Ir.

Supp

.Ir.

Con

t.Ir.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Therea

retwopo

ssiblewaysthatirrationa

litymay

beinvolved.First,

defin

ition

sofp

anicoft

eninclu

deexaggeratedbeliefsaboutthreata

ndoverreactio

nsandso

on.Secon

distheideathatthea

ctof

escape

may

beself-defeating.

(38)

[119]

∙∙

∙∙

(i)Irratio

nalb

ehaviour

isas

ymptom

ofpanic

(ii)R


with

evacuatio

neffi

ciency

Acommon

assumptionregardingindividu

albehavior

inem

ergencyis

that...they

panica

ndreactinan

antisocialand

/orirrationa

lmanner:

they

show

self-preserving

behavior

andlittle

orno

concernfortheir

neighb

ors...ag

reatdealof

solid

arity

andpro-social

behavior

hasb

een

repo

rtedin

such

situatio

ns.

(39)

[119]

∙∙

∙∙

∙

Irratio

nalityisno

tanaccuratetheory

fore

vacuationbehaviou

r

Inthea

ccou

nts,rather

than

theirrationa

lpanicor

smallgroup

behaviou

rthath

asbeen

suggestedin

previous

simulations

ofcrow

dbehaviou

r,survivorso

ftendescrib

edpeop

leform

ingorderly

queues,

actin

gcalm

lydespite

thee

mergencysituatio

n

(40)

[136]

∙∙

∙∙

∙∙

Irratio

nalityisno

tanaccuratetheory

fore

vacuationbehaviou

r

Thejud

gmento

fpanicisusually

maderetrospectiv

ely,especiallyif

serio

uslossof

lifeo

ccurred.

Butw

hatm

aybe

considered

inappropria

te,

excessive,irrationa

lorh

ighlyintenseb

yothersmay

notb

esojudged

byparticip

antsthem

selves.

(41)

[123]

∙∙

∙∙


ct,m

aybe

individu


ofactio

n

Early

accoun

tsof

‘massp

anic’

similarly

suggestedthatcollective

behaviou

rwas

irrationa

lbecause

itwas

governed

byprim

itive

bio-psycho

logicalp

rocesses.

(42)

[132]

∙∙

∙∙

Irratio

nalb

ehaviour

isas

ymptom

ofpanic

Them

ostw

ell-d

ocum

entedof

theseis“

massp

anic.”Th

isrefersto

anexaggeratedor

irrationa

lfearthatissaidto

spread

through

“con

tagion

,”leadingto

escape

behaviorsthatareover-hasty,

unthinking

,and

unrestr

ainedby

socialrules.

(43)

[31]

∙∙

∙∙

∙

Irratio

nalb

ehaviour

isas

ymptom

ofpanic

Inits

morelim

itedandcorrectu

sage,panicdeno

tesirrationa

lbehavior

inwhich

judgmentand

considerationof

reality

factorsa

reso

poor

that

self-destr

uctiv

eactiv

itymay

occur.

(44)

[29]

∙∙

∙∙

∙

(i)Irratio

nalb

ehaviour

isas

ymptom

ofpanic

(ii)R


with

evacuatio

neffi

ciency

Infact,‘panic’in

theform

ofirrationa

lbehaviour

israre

durin

gfires

andresearchersh

avelon

gagorejected

thisconcepttoexplainhu

man

behaviou

rinfire.

(45)

[126]

∙∙

∙∙

Irratio

nalityisno

tanaccuratetheory

fore

vacuationbehaviou

r


Table6:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

H.

Link

sto

P.Def./Ch

a.Ir.

Supp

.Ir.

Con

t.Ir.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Incorrectd

ecision

-makingdu

etoincompleteinformationor

insufficientresou

rces

isno

tthe

samea

sirrationa

ldecision

-makingand

assuch

isno

tsuffi

cienttocategorisesomeone

aspanicking

(46)

[34]

∙∙

∙∙


ct,m

aybe

individu


ofactio

nSime(1980)h

asfully

explainedthea

rgum

entsto

consider

thec

oncept

of‘panic’

asap

oora

ndineffectiv

eexplanationof

human

behaviou

rin

fire.In

fact,‘panic’,in

theform

ofirrationa

lbehaviour,israrein

amajority

offires.

(47)

[26]

∙∙

∙∙

Irratio

nalityisno

tanaccuratetheory

fore

vacuationbehaviou

r

(i)Itispo

ssibleto

arguethatthe

choice

toherd

canbe

resultof

aratio

nald

ecision

(i.e.ac

hoice“

procedurally

reason

ablein

light

ofthe

availablek

nowledgeandmeans

ofcompu

tatio

n”)

(ii)H

erding

behaviou

rcan

bether

esulto

faratio

nald

ecision

-making

processinstead

ofan

“irratio

nal-panic”

decisio

n

(48)

[50]

∙∙

∙∙


ct,m

aybe

individu


ofactio

n

“Qu./Ref.N

o.”m

eans

Quo

te/Reference

number.

“Links

toP.”

means

(Theq

uote)links

Irratio

nality(Ir.)

toPanic(P.).

“Links

toH.”means

(Theq

uote)links

Irratio

nality(Ir.)

toHerding

(H.).

“Def.C

ha.Ir.”

means

(Theq

uote)d

efines/characteris

esIrratio

nality.

“Sup

p.Ir.”m

eans

(Theq

uote)sup

ports(thetheoryof)Irrationality.

“Con

t.Ir.”m

eans

(Theq

uote)c

ontradicts(th

etheory

of)Irrationality.

“Soc.Sci.”means

(Thes

ourceo

fthe

quote)isas

tudy

inSo

cialSciences.

“Phys.Sci.”

means

(Thes

ourceo

fthe

quote)isastu

dyin

PhysicalSciences.

“Bio.Sci.”means

(Thes

ourceo

fthe

quote)

isas

tudy

inBiologicalSciences.

“Mod

.”means

(Thes

ourceo

fthe

quote)

isas

tudy

with

amainfocuso

nMod

ellin

g.“Emp.Test.”m

eans

(Thes

ourceo

fthe

quote)

isastu

dywith

amainfocuso

nEm

piric

alTesting.

“Con

c.”means

(Thes

ourceo

fthe

quote)

isas

tudy

with

amainfocuso

nCon

ceptualisation.

Notethatind

ividualstudies

canbelong

tomultip

lecategorie

s(e.g

.,multip

ledisciplin

es).


Table7:Orig

inalqu

otes

ontheterm

herding.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

P.Link

sto

Ir.

Def./

Cha.

H.

Supp

.H.

Con

t.H.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

(i)Th

ebehaviour

here

istypical

forp

anicsituatio

ns,e.g.the

herdingtend

ency

dominates.

(ii)S

uchab

ehaviour

isrelevant

forp

anicsituatio

nswhere

this

herdingtend

ency

becomes

impo

rtant

andhasb

eenob

served

empiric

ally(o.c.)

(1)

[18]

∙∙

∙∙

(i)Herding

isafeature

ofpanic

behaviou

r(ii)H

erding

iscommon

evacuatio

nbehaviou

r

Wefou

ndan

on-m

onoton

icdepend

ence

ofthee

vacuation

times

onthec

ouplingconstants.

Thesetim

esdepend

onthe

strengthof

theh

erding

behaviou

r,with

minim

alevacuatio

ntim

esforsom

einterm

ediatevalues

ofthe

coup

lings,i.e.,a

prop

ercombinatio

nof

herdinganduse

ofkn

owledgea

bout

thes

horte

stway

tothee

xit.

(2)

[18]

∙∙

∙

Herding

canbe

beneficialto

evacuatio

neffi

ciency

(i)Alargev

alue

ofk 𝐷

impliesa

stron

gherdingbehaviou

rwhich

hasb

eenob

served

thec

aseo

fpanics.

(ii)Th

ebehaviour

hereistypical

forp

anicsituatio

ns,e.g.the

herdingtend

ency

dominates.

(3)

[18]

∙∙

∙∙

(i)Herding

isafeature

ofpanic

behaviou

r(ii)H

erding

iscommon

evacuatio

nbehaviou

r

Mod

elso

fpedestrian

crow

dshave

generatedan

umbero

fsurprisingor

coun

terin

tuitive

predictio

ns.F

orexam

ple,panic

shou

ldindu

ce“sym

metry

breaking

”inwhich

some

availablee

xitsor

escape

routes

from

enclosed

spaces

arejam

med

whileothersgo

under-utilized.

(4)

[100]

∙∙

∙∙

∙

(i)Herding

isafeature

ofpanic

behaviou

r(ii)H

erding

isacommon

mod

ellin

gassumption

Weh

ypothesiz

ethat,un

dertim

eandmon

etarypressure,sub

jects

wou

ldincrease

theirtendencyto

follo

wtheirn

eigh

boursa

ssuggestedin

anearly

mod

elof

crow

dpanics

[o.c.],which

wou

ldgive

riseto

theo

bservedherding

patte

rnun

derh

ighstr

ess.

(5)

[40]

∙∙

∙∙

∙

(i)Stressincreasesh

erding

tend

ency

(ii)H

erding

results

from

follo

wingneighb

ours


Table7:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

P.Link

sto

Ir.

Def./

Cha.

H.

Supp

.H.

Con

t.H.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Whenthep

anichapp

ens,the

agentswanttoevacuateas

quicklyas

possibleandmay

try

tochoo

sethec

losestexit.

Atthe

sametim

e,they

may

have

the

herd

mentality.

(6)

[101]

∙∙

∙∙

Herding

isafeature

ofpanic

behaviou

r

Herding

isstr

ongeru

nder

high

stressthanun

derlow

stress...[but],pedestr

ians

hada

high

erprob

ability

offollo

wing

theirn

eigh

boursw

henstr

essw

ashigh

,sim

plyb

ecause

the

neighb

ourin

gindividu

alsw

ere

moren

umerou

sdue

tothe

increaseddensity

level.Herding,

therefore,resultedfro

mthe

crow

dedn

essa

ndno

tfrom

achange

intheind

ividual

tend

ency

toim

itateneighb

ours.

(7)

[40]

∙∙

∙

(i)Stressincreasesh

erding

tend

ency

(ii)H

erding

tend

ency

ismod

erated

bythec

rowdedn

ess

level

(iii)Herding

isno

tthe

samea

sim

itatio

n

Itremains

uncleartowhatextent

pushing,overcrow

ding

andpeer

imitatio

n[herding

]can

affectthe

efficiency

ofegress.Th

emain

obsta

cletoansw

eringthese

questio

nsisthes

carcity

ofdetailedem

piric

aldata.

(8)

[40]

∙∙

Thee

ffectof

herdingon

evacuatio

neffi

ciency

isun

clear

Alth

ough

peop

leoft

endisplay

obviou

sherding

behavior,their

judgmentm

ayno

tbetofollow

thec

rowd.

(9)

[47]

∙∙

∙∙

Herding

isno

tthe

samea

sim

itatio

n

Manystu

dies

(o.c.)h

avereported

thatherdingbehavior

often

occursin

relativ

elylargen

umber

ofpeop

lein

panics

ituations.

(10)

[47]

∙∙

∙∙

(i)Herding

isafeature

ofpanic

behaviou

r(ii)H

erding

iscommon

evacuatio

nbehaviou

r


Table7:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

P.Link

sto

Ir.

Def./

Cha.

H.

Supp

.H.

Con

t.H.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

(i)Be

causeherdingbehavior

isno

tthe

dominantp

referenceof

peop

le,peacetim

etra

iningof

howto

escape

anacutec

risis

wou

ldbe

critically

impo

rtant.

(ii)W

epresent

novelevidence

show

ingthatpeop

leprefer

searchingfora

nexitand

avoiding

smok

eratherthan

follo

wingthec

rowd[herding

]regardlesswhether

with

intuition

ordelib

erationwhenthec

risis

situatio

nwas

activ

ated.

(iii)Re

liablea

ndconsistent

evidence

show

sthatw

henfacing

acrisis(e.g.,fire),searching

for

anexitandavoiding

smok

eare

preferredby

peop

lerather

than

follo

wingthec

rowd[herding

]

(11)

[47]

∙∙

∙

Herding

isno

tcom

mon

evacuatio

nbehaviou

r

Herding

coeffi

cient...𝛼indicates

anevacuee’s

tend

ency

toem

ulate

others’stra

tegies,and

(1-𝛼)

reflectsthe

degree

towhich

evacuees

prefer

tochoo

setheir

ownstr

ategybasedon

person

alexperie

nces.

(12)

[36]

∙∙

∙

Herding

means

imitatin

g/follo

wing

others/m

ajority

Mostind

ividuals(90%

oftotal

individu

alsinsubw

aysta

tion)

selectthee

vacuationexitthatis

closesttothem

,whileothers

totally

panic(

5%of

total

individu

alsinsubw

aysta

tion)

andfollo

wthefl

owof

thec

rowd

arou

ndthem

[herding

](5%

oftotalind

ividualsin

subw

aysta

tion).

(13)

[16]

∙∙

∙∙

∙

Herding

isafeature

ofpanic

behaviou

r

Whilewec

anthus

ruleoutthe

herdingeffectinou

rexp

erim

ent,

wes

houldpo

into

utthatin

different

scenariostendenciesto

follo

wotherscouldbe

more

prom

inent.Fore

xample,

consider

thec

aseo

fan

environm

entinwhich

thee

xit

routes

arelessc

lear

than

inou

rexperim

ento

revenentirely

unkn

own.

(14)

[52]

∙∙

∙∙

(i)Herding

means

imitatin

g/follo

wing

others/m

ajority

(ii)H

erding

isno

tcom

mon

evacuatio

nbehaviou

r(iii)Herding

tend

ency

ismod

erated

bythelevelof

uncerta

inty


Table7:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

P.Link

sto

Ir.

Def./

Cha.

H.

Supp

.H.

Con

t.H.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Thed

irectionthatmore

pedestr

ians

movingto

ismore

attra

ctive.Such

behavior

isthe

herdingbehavior.

(15)

[137]

∙∙

∙∙

Herding

means

imitatin

g/follo

wing

others/m

ajority

Thee

xcessiv

eherding

behavior

canredu

cethee

vacuation

efficiency.

(16)

[137]

∙∙

Herding

isdetrimentalto

evacuatio

neffi

ciency

Our

study

justinvestigatesthe

fund

amentalcollectivee

ffects

which

fluctuatio

ns,increased

desired

velocities,andherding

behaviou

rcan

have,

independ

ently

ofwhether

all

criteria

ofpanics

arefulfilledor

not.

(17)

[103]

∙∙

∙∙

∙∙

...po

ssiblemechanism

sun

derly

ingthee

ffectso

fescape

panic(regardingan

increase

ofthed

esire

dvelocity,str

ong

frictioneffectsdu

ringph

ysical

interactions,and

herding).

(18)

[19]

∙∙

∙∙

∙

Herding

isafeature

ofpanic

behaviou

r

Incase

ofan

evacuatio

n,peop

lemay

also

beinflu

encedby

the

behavior

ofotherp

eople,and

copy

this...Arie

lyconsidersthis

tobe

herdingbehavior

(19)

[58]

∙∙

∙∙

Herding

means

imitatin

g/follo

wing

others/m

ajority

Them

odelssho

wed

thatpeop

lewereinclin

edto

stayatthe

concerta

reabutw

henthey

saw

othersleaving,they

wereinclin

edto

leavea

swell.Th

eresultsseem

toim

plythatherdingisim

pulsive

(20)

[58]

∙∙

∙∙

Herding

isob

servablein

movem

entinitiatio

n

Thee

ffectof

herdingbehaviou

rmight

bedifferent

whenpeop

leareinak

nown

environm

ent...Collectingdatain

know

nenvironm

entscould

provideinsig

htso

nthis.

(21)

[58]

∙∙

Herding

tend

ency

ismod

erated

bythelevelof

uncerta

inty


Table7:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

P.Link

sto

Ir.

Def./

Cha.

H.

Supp

.H.

Con

t.H.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Kno

wingho

wmuchstr

ess

peop

leexperie

nce,couldshow

differences

inthee

ffectof

herdingon

evacuatio

nchoices

(22)

[58]

∙∙

Herding

tend

ency

ismod

erated

bystr

esslevel

Herding

effect(i.e.,herding

behavior),considered

asa

common

phenom

enon

invario

usfieldssuchas

emergency

evacuatio

nof

largec

rowds,h

ascaught

muchinterestof

scho

lars.

(23) [8]

∙∙

∙

Herding

iscommon

evacuatio

nbehaviou

r

Forlarge

popu

latio

nto

escape

from

dang

erin

aclosedbu

ilding

with

twosymmetric

allylocated

existso

rpaths,herding

effect

means

thattheg

reat

majority

ofpeop

leadoptthe

sameo

nein

escaping

,leaving

theo

ther

one

vacant.

(24) [8]

∙∙

∙∙

Herding

means

imitatin

g/follo

wing

others/m

ajority

(i)Herding

effectu

suallymeans

ineffi

cientu

tilizationof

resources,thus

often

leadingto

inferio

routcomes

inreallife.

(ii)A

symmetric

utilizatio

nof

escaping

exits

inem

ergencydu

eto

herdingeffectw

illdecrease

evacuatio

neffi

ciency

andbring

disastr

ousc

onsequ

ences

(25) [8]

∙∙

∙∙

Herding

isdetrimentalto

evacuatio

neffi

ciency

Herdbehaviou

rism

anifeste

d,with

underutilisa

tionof

other

exits.

(26)

[17]

∙∙

∙∙

Imbalanced

useof

exits

isevidence

forh

erding


Table7:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

P.Link

sto

Ir.

Def./

Cha.

H.

Supp

.H.

Con

t.H.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Asevacuees

choo

seto

follo

wothersdu

ringag

ame,herding

behavior

will

occurinthe

evacuatio

nprocess.

(27)

[37]

∙∙

∙

Herding

means

imitatin

g/follo

wing

others/m

ajority

Weu

setheh

ypothesis

ofherd

behaviou

rtomod

elthe

passengerd

ecision

-making

processthatleads

toself-evacuatio

n

(28)

[43]

∙∙

∙∙

Herding

iscommon

mod

eling

assumption

Inan

emergency,passengerson

thep

eriphery

ofthee

vent

are

usually

unaw

areo

fthe

details

ofthes

ituation.

Rather,these

passengersusually

adopta

herd

mentalityandevacuate

immediatelyfortheirsecurity.

(29)

[43]

∙∙

∙

(i)Herding

iscommon

evacuatio

nbehaviou

r(ii)H

erding

tend

ency

ismod

erated

bythelevelof

uncerta

inty

Wefi

rstintrodu

cean

ewmicroscopicmod

elcharacteriz

edby

anexplorationph

asea

ndan

evacuatio

nph

ase.Th

emain

ingredientso

fthe

mod

elarea

nalignm

entterm,accou

ntingfor

theh

erding

effecttypicalof

uncerta

inbehavior,and

arand

omwalk,accoun

tingforthe

need

toexplorethe

environm

ent

underlim

itedvisib

ility.

(30)

[44]

∙∙

∙

(i)Herding

iscommon

mod

eling

assumption

(ii)H

erding

tend

ency

ismod

erated

bythelevelof

uncerta

inty


Table7:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

P.Link

sto

Ir.

Def./

Cha.

H.

Supp

.H.

Con

t.H.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Thec

rowdcontroltechn

ique

investigatedin

thep

reviou

ssections

relieso

nthefactthat

pedestr

ians

actuallyexhibit

herdingbehavior

inspecial

situatio

ns

(31)

[44]

∙∙

∙

Herding

iscommon

evacuatio

nbehaviou

r

Aprototypesyste

mhasb

een

developed,

which

isableto

demon

stratesomee

mergent

behaviors,such

ascompetitive

queuing,andherdingbehaviors.

(32)

[39]

∙∙

∙

Prod

ucingherdingeffectsisa

common

criterio

nforv

erify

ing

simulationmod

els

Herding

behavior

isoft

enob

served

durin

gthee

vacuation

ofac

rowdin

aroom

with

two

exits—on

eexitiscloggedwhile

theo

ther

isno

tfullyutilized.

(33)

[39]

∙∙

∙∙

Imbalanced

useof

exits

isevidence

forh

erding

One

well-k

nownexam

pleo

fsocialproofu

nder

emergency

situatio

nsistheh

erding

behavior—whenun

derh

ighly

uncerta

inandstr

essfu

lsituatio

ns,anindividu

altend

sto

follo

wothersalmostb

lindly.

(34)

[39]

∙∙

∙∙

(i)Herding

means

imitatin

g/follo

wing

others/m

ajority

(ii)S

tressincreasesh

erding

tend

ency

(iii)Herding

tend

ency

ismod

erated

bythelevelof

uncerta

inty

Sometim

esherdingbehavior

helpsp

eopletoexitsafely,

andat

othertim

es,the

herdingbehavior

may

lead

peop

leto

adeadendor

causethe

blockageso

fsom

eexits

even

thou

ghothere

xitsaren

otfully

utilized.

(35)

[39]

∙∙

∙

Thee

ffectof

herdingon

evacuatio

neffi

ciency

isun

clear

Build

ingdesig

ners

often

assume

thatac

rowdwou

ldexitevenly

amon

gmultip

leexits

ofar

oom

incase

ofan

emergency;

however,herding

behavior

invalid

ates

such

anassumption.

(36)

[39]

∙∙

∙∙

Imbalanced

useof

exits

isevidence

forh

erding


Table7:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

P.Link

sto

Ir.

Def./

Cha.

H.

Supp

.H.

Con

t.H.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Inthispaperthe

evacuatio

ncrow

dsyste

misabstr

actedinto

adynamiccomplex

network

compo

sedof

threetypeso

fpeop

le,n

amelyc

alm

peop

le,

panicp

eople,andherdingpeop

le,

aswellastheirinteractions.

(37)

[105]

∙∙

∙∙

Herding

iscommon

mod

eling

assumption

Ifotherp

eople’s

behaviorssho

wa

high

levelofirrationality,such

asscream

ing,rushing,colliding

,pu

shing,etc.,

which

provide

salient

evidence

aboutp

anic

emotion...one

who

hasa

certa

inherdinglevelw

illtend

tobe

“infected”a

ndalso

present

irrationalp

anicbehavior

(38)

[105]

∙∙

∙∙

∙∙

Herding

iscommon

evacuatio

nbehaviou

r

Thee

vacuationof

pedestr

ians

from

asmok

e-filledroom

with

twoexits

canlead

toherding

behaviou

rand

clogging

aton

eof

thee

xits.

(39)

[38]

∙∙

∙∙

Imbalanced

useof

exits

isevidence

forh

erding

Duringevacuatio

n...Ex

itbehaviorssuchas

follo

wing

leaderso

rherding

toan

exitare

common

lyob

served.

(40)

[138]

∙∙

∙

Herding

iscommon

evacuatio

nbehaviou

r

Thea

gentsc

hoosetheira

ctions

andevacuatio

nroutes

byconsideringindividu

alpreferences,as

wellasthe

roles

andtheb

ehaviorsof

the

mem

bersin

thes

ocialgroup

and

othern

eigh

borin

gagents

[herding

].

(41)

[138]

∙∙

Herding

isno

tthe

sole

determ

inanto

fthe

behaviou

r

Inadditio

nto

static

anddynamic

fields,thee

xtendedmod

eladopts

thes

mok

eand

herdingfieldsto

reflectpedestr

ian’s

smok

e-avoiding

behavior

and

herdingbehavior.

(42)

[137]

∙∙

∙

Herding

iscommon

mod

eling

assumption


Table7:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

P.Link

sto

Ir.

Def./

Cha.

H.

Supp

.H.

Con

t.H.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Thed

irectionthatmore

pedestr

ians

movingto

ismore

attra

ctive.Such

behavior

isthe

herdingbehavior.

(43)

[137]

∙∙

∙

Herding

means

imitatin

g/follo

wing

others/m

ajority

Stud

yof

collectiveb

ehavioro

fmiceh

asreceived

increasin

gattentionin

thefi

eldof

evacuatio

n.Ba

sedon

mice,

scale-fre

ebehavior

[o.c.],herd

mentality[o.c.],learning

experie

nce[o.c.],etc.have

been

investigated.

(44)

[90]

∙∙

∙

Herding

theory

inevacuatio

nhas

been

influ

encedby

anim

almod

elso

fbehaviour

Helbing

etal.propo

sedthe

igno

ranceof

availablee

xits

mod

el,w

hich

suggestedthat

neith

ersim

pleind

ividualistic

nor

herdingbehavior

isoptim

alfor

escaping

(45)

[59]

∙∙

Mixture

ofherdingand

individu

alisticbehavior

isbeneficialtoevacuatio

ns

Pure

herdingbehaviou

rinfers

thatthew

holecrow

deventually

moves

inthes

amed

irection

whileothera

vailablee

xitsaren

oteffi

ciently

used.

(46)

[59]

∙∙

∙

Imbalanced

useof

exits

isevidence

forh

erding

Somes

tudies

have

suggestedthat

thed

irectionof

influ

ence

issuch

thatwetendto

copy

thed

ecision

ofthem

ajority,and

thistend

ency

isoft

enreferred

toas

“herd

behaviou

r”.

(47)

[53]

∙∙

∙

Herding

means

imitatin

g/follo

wing

others/m

ajority

Herdbehaviou

rhas

been

assumed

byac

onsid

erablebo

dyof

literature(m

ostly

theoretical

studies)a

sacommon

default

behaviou

ralfeature

ofpedestr

ian

evacuees.

(48)

[45]

∙∙

Herding

iscommon

mod

eling

assumption

Results

also

suggestedthata

simpleh

erd-mod

elmay

not

suffice

asad

efaultun

iversal

assumptionforrealistic

replicationof

evacuees’

directionalcho

ices

(49)

[45]

∙∙

∙

Pure

herdingisno

tanaccurate

mod

elingassumption


Table7:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

P.Link

sto

Ir.

Def./

Cha.

H.

Supp

.H.

Con

t.H.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Thes

ymmetry

breaking

[herding

]observedin

nature

isfascinating.Th

issymmetry

breaking

isob

served

inboth

human

crow

dsandantcolon

ies.

Insuch

cases,whenescaping

from

aclosedspacew

ithtwo

symmetric

allylocatedexits,one

exitisused

moreoft

enthan

the

other.

(50)

[60]

∙∙

∙∙

(i)Im

balanced

useo

fexitsis

evidence

forh

erding

(ii)H

erding

theory

inevacuatio

nhasb

eeninflu

encedby

anim

almod

elso

fbehaviour

(i)Wes

tudy

thee

fficacy

ofallelomim

esis[herding

]asa

nescape

strategyof

mobile

agents

(pedestrians)thataim

toleavea

two-exitroom

with

inthe

shortestpo

ssibletim

e.(ii)A

llelomim

esisisthea

ctof

copyingon

e'skind

redneighb

ors.

(iii)Allelomim

esisprovides

asim

pley

etversatile

mechanism

forstudyingthee

gressb

ehavior

ofconfi

nedcrow

dsin

amulti-exitroom

.

(51)

[46]

∙∙

∙

(i)Herding

iscommon

mod

eling

assumption

(ii)H

erding

means

imitatin

g/follo

wing

others/m

ajority

Itisno

thardto

seethat

allelomim

esis[herding

]isa

plausib

lemechanism

ford

riving

thee

mergenceo

fherdbehavior

incrow

dsandanim

algroups.

(52)

[46]

∙∙

∙∙

Herding

theory

inevacuatio

nhas

been

influ

encedby

anim

almod

elso

fbehaviour

Whenorientationandvisib

ility

ispo

or,suchas

insm

oke-filled

room

soro

vercrowdedareas,

onlythelocalinform

ationis

accessibleto

each

pedestr

ian.

The

situatio

nencourages

pedestr

ians

tobase

theird

ecision

sonwhat

they

know

,thu

scopying

the

actio

nsof

theirimmediate

neighb

ors,which

may

resultto

herding.

(53)

[46]

∙∙

∙∙

(i)Herding

means

imitatin

g/follo

wing

others/m

ajority

(ii)H

erding

tend

ency

ismod

erated

bythelevelof

uncerta

inty


ble7:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

P.Link

sto

Ir.

Def./

Cha.

H.

Supp

.H.

Con

t.H.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Thea

ssum

ptionof

herd-like

behaviou

rdoesn

otnecessarily

applytoallcon

textso

fevacuatio

nsanditshou

ldbe

considered

inconjun

ctionwith

them

oderatingroleof

context-s

pecific

factors,

particularly

thelevelof

inform

ationavailableto

individu

alevacuees.

(54)

[48]

∙∙

(i)Herding

isno

tcom

mon

evacuatio

nbehaviou

r(ii)H

erding

tend

ency

ismod

erated

bythelevelof

uncerta

inty

Wefou

ndthatthea

nts

demon

strated

thep

heno

menon

of“sym

metry

breaking”

[herding

]inthisstr

esssitu

ation.

(55)

[61]

∙∙

Herding

theory

inevacuatio

nhas

been

influ

encedby

anim

almod

elso

fbehaviour

Blindcopyingprom

otes

herding

behavior

inanim

algroups

often

with

dire

consequences

toparticip

ants.

(56)

[91]

∙∙

∙

Herding

theory

inevacuatio

nhas

been

influ

encedby

anim

almod

elso

fbehaviour

Abinary

logitm

odelisprop

osed

show

ingthattheo

ccurrences

ofHB[herding

behaviou

r]are

affectedby

both

environm

ental

andperson

alfactors.In

particular,them

odelshow

sthat

thep

ersonalaptitu

deto

HBcan

have

akey

rolein

selectingan

exit.

(57)

[50]

∙∙

Herding

tend

ency

shou

ldbe

considered

inconjun

ctionwith

individu

aldifferences

Threetypeso

finteractio

nsam

ongevacuees

have

been

identifi

ed:H

B(i.e.follo

wing

others’behaviour),coop

erative

behaviou

r(i.e.w

orking

oractin

gtogether

forthe

common

/mutual

benefit)a

ndcompetitive/selfish

behaviou

r

(58)

[50]

∙∙

Herding

tend

ency

shou

ldbe

considered

inconjun

ctionwith

individu

aldifferences

HBoccurswhenevera

decisio

n-maker

prefers,am

ong

different

optio

ns,tofollo

wother

peop

le’sc

hoices.A

sregards

tothe

exitchoice,thisc

anbe

explained

bythed

ecision

ofthee

vacuee

tochoo

sean

exitjustbecauseother

evacuees

hadselected

it,inste

adof

strivingto

identifythee

xitthat

wou

ldprovidethem

with

the

bestevacuatio

ncond

ition

s.

(59)

[50]

∙∙

∙

(i)Herding

means

imitatin

g/follo

wing

others/m

ajority

(ii)Imbalanced

useof

exits

isevidence

forh

erding

Theliterature

argues

thatHB

couldhave

both

positiveand

negativ

eeffectsd

epending

onthe

evacuatio

ncond

ition

s

(60)

[50]

∙∙

Thee

ffectof

herdingon

evacuatio

neffi

ciency

isun

clear


Table7:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

P.Link

sto

Ir.

Def./

Cha.

H.

Supp

.H.

Con

t.H.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

thed

egreeof

uncerta

inty

can

makethe

differenceinthec

hoice

since

theh

igherthe

uncerta

inty

them

oredecisio

n-maker

could

manifestHB.

(61)

[50]

∙∙

Herding

tend

ency

ismod

erated

bythelevelof

uncerta

inty

Them

odelshow

sthatthe

prob

ability

ofhaving

anoccurrence

ofHBdecreasesw

iththeincreaseof

thed

ifference

betweenthen

umbero

fpersons

closetothem

ostcrowdedexit

andtheleastcrow

dedexit...

whatthism

eans

isthatwhenthis

differenceisvery

high

,adecisio

nmaker

prefersthe

leastcrowed

exit

(62)

[50]

∙∙

∙

Herding

tend

ency

ismod

erated

bythec

rowdedn

esslevel

This“follow-th

e-crow

d”[herding

]behaviorw

asprop

osed

asap

ossib

lebehavior

ofsim

ulated

humans

(63)

[139]

∙∙

∙

Herding

iscommon

evacuatio

nbehaviou

r

Herding

happ

ensw

henordinary

peop

lebehave

asag

roup

,effectiv

elysurrenderin

gtheir

ability

tofunctio

nas

individu

als.

Inpanics

ituations

where

decisio

nshave

tobe

made

quicklyun

derd

uressitislikely

forind

ividualsto

lose

their

ability

todecide

ontheiro

wn.

Inste

ad,these

impaire

dindividu

alstendto

imitatethe

actio

nof

theirn

eigh

bors.Th

etend

ency

torelyon

othersisa

prod

ucto

fexp

erience.

(64)

[140]

∙∙

∙∙

∙

(i)Herding

isafeature

ofpanic

behaviou

r(ii)H

erding

means

imitatin

g/follo

wing

others/m

ajority

Thes

everecong

estio

nandhigh

pressuresthatareindu

cedor

worsenedby

herdingcontinue

toexacta

high

costto

societyin

term

sofinfrastr

ucture

damage

andlossof

lifea

ndlim

b

(65)

[140]

∙∙

∙

Herding

isdetrimentalto

evacuatio

neffi

ciency


Table7:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

P.Link

sto

Ir.

Def./

Cha.

H.

Supp

.H.

Con

t.H.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Theroleo

fherding

inescape

panic

hasb

eenstu

died

usingequatio

nsof

motionin

thep

resenceof

interaction

forces

[o.c.].How

ever,quantitativ

ecomparison

sbetweenmod

elpredictio

nandexperim

entalresult

have

remainedscarce.

(66)

[140]

∙∙

∙

Herding

theory

isin

need

ofem

piric

altesting

Them

icee

xhibitedherdingbehavior

whileescaping

from

apoo

lofw

ater

inatwo-exitflo

oded

cham

ber.

(67)

[140]

∙∙

∙

Herding

theory

inevacuatio

nhas

been

influ

encedby

anim

almod

elso

fbehaviour

Thep

heno

menon

ofherdingisav

ery

generalfeature

ofthec

ollective

behavior

ofmanys

pecies

inpanic

cond

ition

s,inclu

ding

humans.Ithas

been

predictedtheoretically

that

panicind

uced

herdingin

individu

als

confi

nedto

aroom

canprod

ucea

non-symmetric

aluseof

twoidentical

exitdo

ors.Herew

edem

onstr

atethe

existence

ofthatph

enom

enon

inexperim

ents,

usingantsas

amod

elof

pedestr

ians...Our

experim

ental

results,com

binedwith

theoretical

mod

els,suggestthatsom

efeatureso

fthec

ollectiveb

ehavioro

fhum

ans

andantscan

bequ

itesim

ilarw

henescaping

under

panic.

(68)

[62]

∙∙

∙∙

∙

(i)Herding

isafeature

ofpanic

behaviou

r(ii)H

erding

iscommon

evacuatio

nbehaviou

r(iii)Im

balanced

useof

exits

isevidence

forh

erding

(iv)H

erding

theory

inevacuatio

nhasb

eeninflu

enced

byanim

almod

elso

fbehaviour

(i)Herding

preventedthefull

utilizatio

nof

thetwoexits

bythe

escaping

mice.

(ii)A

tthe

height

ofpanic,

allelomim

etictend

encies

dominate

over

individu

aldecisio

ns,givingrise

toherding.

(69)

[92]

∙∙

∙∙

∙

(i)Herding

means

imitatin

g/follo

wing

others/m

ajority

(ii)Imbalanced

useof

exits

isevidence

forh

erding

Peop

lein

adarkor

smok

yroom

are

mim

ickedby

“blin

d”stu

dents

wearin

geyem

asks...

Surprisingly,adding

moreexits

does

notimprovethes

ituationin

the

expected

way,since

mostp

eopleuse

thee

xitthatisd

iscovered

first,

which

may

beview

edas

akindof

herding

effectb

ased

onno

nlocal,but

direct

acou

sticinteractions.

(70)

[141]

∙∙

∙∙

(i)Im

balanced

useo

fexitsis

evidence

forh

erding

Journal of Advanced Transportation 51Ta

ble7:Con

tinued.

Quo

tes

Qu.Re

f.No.

Implications

oftheq

uote

Thes

ourcestu

dyCom

ments/Interpretatio

nsDisc

iplin

eStud

ytype

Link

sto

P.Link

sto

Ir.

Def./

Cha.

H.

Supp

.H.

Con

t.H.

Soc.Sci.

Phys.

Sci.

Bio.Sci.

Mod

.Em

p.Test.

Con

c.

Herdbehaviou

rism

anifeste

d,with

underutilisa

tionof

othere

xits...Th

echoice

mod

elprop

osed

inthiswork

isbasedon

the‘herdingbehaviou

r’:in

apanicsituatio

n,theind

ividualis

inclined

nottobehave

autono

mou

sly,

buttoim

itateandfollo

wthe

surrou

ndingperson

s

(71)

[17]

∙∙

∙∙

∙

(i)Im

balanced

useo

fexitsis

evidence

forh

erding

(ii)H

erding

isafeature

ofpanic

behaviou

r(iii)Herding

means

imitatin

g/follo

wing

others/m

ajority

Hum

ansd

ono

ttendto

imitate

directionchoiceso

fthe

majority

[herding

].To

thec

ontra

ry,theytend

toavoidthed

irectionchosen

bythe

majority,and

theb

iggerthe

majority

is,thelesslikelytheyaretofollo

wit.

Theh

igh-urgencytre

atment

(assum

edto

beassociated

with

high

erdegreeso

fstre

ss)d

idno

treverse,no

rdid

itdecrease

this

avoid-the-majority

tend

ency.If

anything

,itevenam

plified

itin

certa

inchoice

situatio

ns.

(72)

[41]

∙∙

∙∙

Stressdo

esno

tincreaseim

itatio

ntend

ency

[indirectionchoices]

Theg

enerallevelofcrowding

(i.e.the

totaln

umbero

fpeopleinthe

choice-m

aker’svicinity)isa

nother

factor

thatcanmod

eratethe

reactio

nto

peers’decisio

n.Higherlevelso

fcrow

ding

also

amplified

the

avoid-the-crow

dtend

ency

[opp

osite

theh

erding

]incerta

indirection

choice

scenarios.

(73)

[41]

∙∙

∙

Herding

tend

ency

ismod

erated

bythec

rowdedn

esslevel

Imitativ

e(herd)b

ehaviour

indirectiondecisio

n-makinghind

ers

efficiency

ofcrow

devacuatio

nprocesses

(74)

[49]

∙∙

Herding

isdetrimentalto

evacuatio

neffi

ciency

“Qu./Ref.N

o.”m

eans

Quote/Refe

rencen

umber.

“Links

toP.”

means

(Theq

uote)links

Herding

(H.)toPa

nic(P.).

“Links

toIr.”m

eans

(Theq

uote)links

Herding

(H.)toIrr

ationa

lity(Ir.).

“Def.C

ha.H

.”means

(Theq

uote)d

efines/c

haracte

risesHerding.

“Sup

p.H.”means

(Theq

uote)supports(thetheoryof)H

erding.

“Con

t.H.”means

(Theq

uote)contra

dicts(thetheoryof)H

erding.

“Soc.Sci.”means

(Thesourceo

fthe

quote)isastu

dyin

Socia

lScie

nces.

“Phys.Sci.”

means

(Thesourceo

fthe

quote)isastu

dyin

Physica

lScie

nces.

“Bio.Sci.”means

(Thesourceo

fthe

quote)isastu

dyin

Biologica

lScie

nces.

“Mod

.”means

(Thesourceo

fthe

quote)isastu

dywith

amainfocuso

nModelling.

“Emp.Test.”m

eans

(Thesourceo

fthe

quote)isastu

dywith

amainfocuso

nEm

piric

alTesting.

“Con

c.”means

(Thesourceo

fthe

quote)isastu

dywith

amainfocuso

nCo

nceptualisa

tion.

Notethatind

ividua

lstudiescanbelong

tomultip

lecategorie

s(e.g

.,multip

ledisciplin

es).


Table8:Re

view

summaryof

thee

mpiric

alstu

dies

onherding.

Ref.

Aspectof

behaviou

rEx

perim

entm

etho

dEv

idence

ofherding

Furth

erdetails

Exit(dire

ction)

choice

Exit

(dire

ction)

choice

changing

Reactio

ntim

eHum

ancrow

dsVirtu

alreality

Ants

Mice

Observed

Not

observed

[62]

∙∙

∙

Herding

observed

intheform

ofasym

metric

useof

exits

by‘panicked’ants

[59]

∙∙

∙

Thed

egreeof

asym

metry

increased

linearly

with

thetem

perature

[60]

∙∙

∙

Thed

egreeof

asym

metry

increased

then

decreasedby

ants’

density

[61]

∙∙

∙

Antsu

nder

stressd

emon

strated

the

phenom

enon

of“sym

metry

breaking”.

[42]

∙∙

∙∙

Symmetry

breaking

was

associated

with

thed

ifference

inthew

idth

ofexitin

prop

ortio

nalw

ays

[140]

∙∙

∙

Them

icee

xhibitedherding

behaviou

rwhileescaping

from

apo

olof

water

inatwo-exitflo

oded

cham

ber

[92]

∙∙

∙

Them

ouse

experim

entsyielded

lower

throughp

utscaused

byherding.Herding

preventedthefull

utilizatio

nof

thetwoexits.

[91]

∙∙

∙

Theo

ccurrenceof

blindcopyingis

suggestedby

theu

neven(biased)

utilizatio

nof

thea

vailable

pool

spacea

ndexits

byun

trained

mem

bersespeciallyin

thelarger

30-m

ouse

groups

[52]

∙∙

∙

Experim

entsin

interactive

virtu

al-realitysetting

ruledoutthe

herdingeffect

[54]

∙∙

∙

[Inano

n-crow

dedvirtu

altunn

elevacuatio

n],p

articipantsun

der

socialinflu

ence

treatmentw

ere

morelikelytofollo

wthev

irtual

agent

[55]

∙∙

∙∙

(i)[In

anon

-crowdedvirtu

altunn

elevacuatio

n],P

articipants

werelesslikelytomovetothe

emergencyexitin

thec

onflict

cond

ition

scomparedto

then

o-confl

ict

cond

ition

.(ii)Th

epresenceof

passivev

irtual

agentm

ades

ubjectsd

elay

their

movem

entreaction


Table8:Con

tinued.

Ref.

Aspectof

behaviou

rEx

perim

entm

etho

dEv

idence

ofherding

Furth

erdetails

Exit(dire

ction)

choice

Exit

(dire

ction)

choice

changing

Reactio

ntim

eHum

ancrow

dsVirtu

alreality

Ants

Mice

Observed

Not

observed

[56]

∙∙

∙

(i)[In

anon

-crowdedvirtu

altunn

elevacuatio

n],exitcho

iceis

jointly

influ

encedby

both

exit

familiarity

andby

thee

gress

behaviou

rofn

eigh

bours.

(ii)S

ocialinfl

uenceincreases

with

then

umbero

fneigh

bours

[50]

∙∙

∙

Occurrences

ofherding

behaviou

rare

affectedby

both

environm

entaland

person

alfactors.

[47]

∙∙

∙

Peop

leprefer

searchingfora

nexitandavoiding

smok

erather

than

follo

wingthec

rowd

[40]

∙∙

∙

Theo

bservedherdingpatte

rns

dono

tresultfrom

achang

ein

theh

erding

tend

ency

butinstead

from

thec

rowdedn

ess

[58]

∙∙

∙

(i)Th

emorepeop

lesomeone

sees

leaving,the

moreinclined

thisperson

isto

leave.

(ii)S

eeingpeop

leleaveh

asmore

impactthan

seeing

peop

lesta

y.

[64]

∙∙

∙

(i)So

cialinflu

ence

isan

impo

rtant

factor

inreactio

ntim

eespeciallywhenfirec

ueis

unclear

(ii)S

ocialinfl

uence(

onreactio

ntim

e)increasesw

ithdecreasin

gdista

nceb

etweenvisitors.

[48]

∙∙

∙

Socialinflu

ence

(onexitchoice)

ismod

erated

bythelevelof

decisio

nam

biguity


Table8:Con

tinued.

Ref.

Aspectof

behaviou

rEx

perim

entm

etho

dEv

idence

ofherding

Furth

erdetails

Exit(dire

ction)

choice

Exit

(dire

ction)

choice

changing

Reactio

ntim

eHum

ancrow

dsVirtu

alreality

Ants

Mice

Observed

Not

observed

[45]

∙∙

∙

(i)So

cialinflu

ence

(onexit

choice)d

oesn

otnecessarily

increasesw

ithdecreasin

gdista

nceb

etweenindividu

als.

(ii)[In

acrow

dedevacuatio

n],

exitchoice

isjointly

influ

enced

byboth

socialinteractions

and

physicalfactors

(iii)So

cialinflu

ence

increases

with

then

umbero

fneigh

bours

[53]

∙∙

∙

(i)So

cialinflu

ence

ismod

erated

bythee

ffectof

individu

aldifferences

(ii)S

ocialinfl

uence(onexit

choice)d

oesn

otnecessarily

act

tothed

irectionof

herding

[41]

∙∙

∙

(i)So

cialinflu

ence

actsto

the

oppo

siteof

herding

(ii)S

tressdo

esno

tincrease

imitatio

ntend

ency

(iii)Th

enum

bero

fneigh

bours

mod

eratethe

socialinflu

ence

[49]

∙∙

∙

Mis-specify

ingherdingtend

ency

cansubstantially

bias

mod

ellin

goutcom

es

[65]

∙∙

∙∙

∙

(i)Individu

alssho

wclear

imitativ

etend

ency

inchanging

theire

xitcho

iced

ecision

s(ii)Ind

ividualsdo

notsho

wherdingtend

ency

intheire

xit

choices

(iii)Herding

tend

ency

ofindividu

als(in

exitchoice)d

oes

notincreaseby

stress

[66]

∙∙

∙∙

∙

(i)So

cialgroups

show

clear

imitativ

etend

ency

inchanging

theire

xitcho

iced

ecision

s(ii)S

ocialgroup

sdono

tsho

wherdingtend

ency

intheire

xit

choices

(iii)Herding

tend

ency

ofgroups

(inexitchoice)d

oesn

otincrease

bystr

ess


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