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Happy to Help? A systematic review and meta-analysis of the effects of performing acts of kindness on the well-being of the actor
Oliver Scott Curry
University of Oxford
Lee Rowland
University of Bournemouth
Sally Zlotowitz
University College London
John McAlaney
University of Bournemouth
Harvey Whitehouse
University of Oxford
Author Note
Oliver Scott Curry, Institute of Cognitive and Evolutionary Anthropology, University
of Oxford; Lee Rowland, Department of Psychology, University of Bournemouth; Sally
Zlotowitz, Department of Clinical Educational and Health Psychology, University College
London; John McAlaney, Department of Psychology, University of Bournemouth; Harvey
Whitehouse, Institute of Cognitive and Evolutionary Anthropology, University of Oxford
This work on this article was supported by kindness.org. Thanks to Caspar van Lissa
and Rongqin Yu for statistical advice, to Rosalind Arden for useful discussions, to Helena
Cronin for comments on the manuscript, and to Steve Rowland and Emma Seymour for
research assistance.
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Correspondence concerning this article should be addressed to Oliver Scott Curry,
Institute of Cognitive and Evolutionary Anthropology, University of Oxford, 64 Banbury
Road, Oxford, OX2 6PN.
E-mail: [email protected]
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Abstract
Does being kind make you happy? Recent advances in the behavioural sciences have
provided a number of explanations of human social, cooperative and altruistic behaviour.
These theories predict that people will be ‘happy to help’ family, friends, community
members, spouses, and even strangers under some conditions. Here we conduct a systematic
review and meta-analysis of the experimental evidence that kindness interventions (for
example, performing ’random acts of kindness’) boost subjective well-being. Our initial
search of the literature identifies 428 articles; of which 19 (21 studies) meet the inclusion
criteria (total N=2,685). We find that the overall effect of kindness on well-being is small-to-
medium (d = 0.36). There is also some indication of publication bias – lower quality studies
tended to find larger effects – suggesting that the true effect size may be smaller still (0.29 ≤
d ≤ 0.33). We recommend that future research: distinguish between the effects of kindness to
specific categories of people; take kindness-specific individual differences into account; and
consider a wider range of distal outcome measures. Such research will advance our
understanding of the causes and consequences of kindness, and help practitioners to
maximise the effectiveness of kindness interventions.
Keywords: kindness, altruism, happiness, well-being, positive psychology
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Happy to Help? A systematic review and meta-analysis of the effects of performing acts
of kindness on the well-being of the actor
Does being kind make you happy? Does doing good make you feel good? Over the
past few decades, advances in the behavioural sciences have developed numerous theories of
human social, cooperative and altruistic behaviour. These theories — kin altruism,
mutualism, reciprocal altruism, and competitive altruism — make it possible to explain a
variety of different ‘kinds of kindness’ (for example, love, sympathy, gratitude and heroism).
And they predict that people will be ‘happy to help’ family, friends, community members,
spouses, and even strangers under some conditions.
More recently, there has been growing interest in using kindness as an intervention to
boost ‘subjective well-being’ (including happiness, life-satisfaction and positive affect). The
idea that, for example, ‘random acts of kindness’ boosts the well-being, happiness and mental
health not only of the recipient, but also the actor has been taken up and promoted by a large
number of research groups and charity organisations (see S1). The idea has even been
explored by the UK government (Aked, Marks, Cordon, & Thompson, 2008; Aked &
Thompson, 2011; Huppert, 2009; Laura Stoll, 2011). It has been argued that altruism —
acting at a cost to benefit others – benefits the altruist as well as the beneficiary. The appeal
of this ‘good news story’ is obvious: if it is true that ‘helping helps the helper’, then
encouraging people to be kind(er) to others could provide a is a simple, effective, inexpensive
and widely-available means of addressing social problems ranging from social isolation to
more serious mental and physical health conditions.
Here we outline existing theories of altruism and their relation to kindness, and
consider the predictions these theories make about well-being. And we conduct a systematic
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review and meta-analysis of previous experimental studies of the effects of kind acts on the
well-being of the actor. We end with a discussion of the limitations of the existing literature,
and make recommendations for future research.
The causes of kindness
Why and under what circumstances are people kind to others? Why do people behave
prosocial, cooperative and altruistic ways? Recent interdisciplinary research has provided a
wealth of answers to these questions. 1
Humans are social animals. Their ancestors have been living in social groups for over
50 million years (Shultz, Opie, & Atkinson, 2011), and for the past 2 million years humans
have been making a living as intensely collaborative hunter-gathers (Tooby & DeVore, 1987).
Social life affords numerous opportunities for mutually beneficial cooperative interactions.
And humans, like other social animals, have been equipped by natural selection with a
variety of traits and dispositions – love, loyalty, benevolence and bravery – that enable them
to seize these opportunities. In addition, the human capacity for culture – the ability to invent
and share new ways of living – has allowed them to build and elaborate upon this benevolent
biological foundation, with rules, norms and other social institutions that further inculcate
and amplify cooperation and altruism (Hammerstein, 2003).
According to game theory – the mathematical analysis of social interaction – there is
not just one type of cooperation, there are many, and hence many different types of social,
cooperative and altruistic behaviour (Curry, 2016; Lehmann & Keller, 2006; Nunn & Lewis,
2001; Sachs, Mueller, Wilcox, & Bull, 2004). These theories make it possible to identify and
explain several different ‘kinds of kindness’.
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People will be kind to their families
Natural selection will favour altruism when the cost to the acting gene is outweighed
by the benefits to copies of that gene that reside in other individuals – that is in genetic
relatives or family members (Dawkins, 1979; Hamilton, 1964). As predicted by this theory of
‘kin selection’, many organisms possess adaptations for detecting and delivering benefits (or
avoiding harm) to kin (Gardner & West, 2014) — the most common example being parental
care of offspring (Clutton-Brock, 1991; Royle, Smiseth, & Kölliker, 2012). Humans have
always lived in groups composed mostly of genetic relatives (Chapais, 2014; Walker, 2014),
and there is evidence to suggest that they too possess adaptations for kin altruism. Humans
detect kin by means of a variety of cues, including maternal perinatal association, co-
residence (Lieberman, Tooby, & Cosmides, 2003, 2007), and possibly phenotype matching
(DeBruine, 2005; Mateo, 2015). A preference for helping kin has been demonstrated in
numerous experiments (Curry, Roberts, & Dunbar, 2013; Madsen et al., 2007). And human
kin altruism is evident in patterns of parental (Geary & Flinn, 2001) and grandparental (Euler
& Weitzel, 1996) investment and its absence (Daly & Wilson, 1996). It has also been argued
that sympathy – a sensitivity to the needs of others – originally evolved to facilitate parental
care (Hublin, 2009; Preston & de Waal, 2002), before becoming available to facilitate other
types of cooperation.
Thus, kin selection can explain kindness in the form of love, care, sympathy and
compassion. And the theory predicts that these tendencies will be elicited by others who
exhibit cues of genetic relatedness, especially vulnerable children. Consistent with this
perspective, research has shown that men are more willing to donate money to children
whose faces have been digitally morphed to resemble their own (Platek, Burch, Panyavin,
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Wasserman, & Gallup Jr, 2002); and people are more generous when donating to charities
using images of children with negative (sad, distressed) as opposed to neutral emotional
expressions (Burt & Strongman, 2005; Small & Verrochi, 2009).
People will be kind to members of their communities
Natural selection will favour altruism to those with whom the actor shares a common
interest – team mates, group members, coalition partners, and others who are ‘in the same
boat’. Game theorists typically model such ‘mutualistic’ interactions as coordination
problems (D. K. Lewis, 1969; Schelling, 1960) – including ‘stag hunts’ (Skyrms, 2004) and
‘soldiers dilemmas’ (Clutton-Brock, 2009). The benefits of ‘working together’ are evident
from the ubiquity in nature of herds, shoals, flocks, and collaborative hunting (Boinski &
Garber, 2000; Boos, Kolbe, Kappeler, & Ellwart, 2011), as well as the formation of alliances
and coalitions (Bissonnette et al., 2015; Harcourt & de Waal, 1992). Coordinating to mutual
advantage has been a recurrent feature of the social lives of humans and their recent
ancestors, especially with regard to collaborative hunting (Alvard, 2001; Alvard & Nolin,
2002), and forming coalitions to compete with rival coalitions (Wrangham, 1999). Humans
have psychological adaptations for detecting coalitions by means of a variety of different
‘badges of membership’ (Kurzban, Tooby, & Cosmides, 2001; McElreath, Boyd, &
Richerson, 2003; Pietraszewski, Curry, Petersen, Cosmides, & Tooby, 2015; Tooby &
Cosmides, 2010); and they spontaneously form, and are altruistic to, their own groups
(sometimes at the expense of other groups) (Balliet, Wu, & De Dreu, 2014; Bernhard,
Fischbacher, & Fehr, 2006; Sherif, Harvey, White, Hood, & Sherif, 1954/1961; Tajfel, 1970).
Coordination to mutual advantage also seems to have spurred the evolution of a sophisticated
‘theory of mind’ – the ability to think about what others are thinking and feeling (Tomasello,
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Carpenter, Call, Behne, & Moll, 2005; Young, Camprodon, Hauser, Pascual-Leone, & Saxe,
2010).
Thus, mutualism (coordination to mutual advantage) can explain kindness in the form
of loyalty, solidarity, camaraderie, civic-mindedness, community spirit, and commitment to a
cause ‘greater than oneself’. And the theory predicts that these tendencies will be elicited by
other members of the groups with which one identifies (including strangers) (Whitehouse &
Lanman, 2014). Consistent with this perspective, research has demonstrated that geographical
proximity (and perhaps perceptions of cultural and genetic similarity) is a major predictor of
the size of U.S. donations to foreign communities affected by large scale natural disasters
(Adams, 1986). Research has also shown that participants primed with words related to
‘connectedness’ (for example, ‘community’, ‘together’, ‘connected’, ‘relationship’) donated
more money to charity (Pavey, Greitemeyer, & Sparks, 2011).
People will be kind to their friends, and others whom they might meet again
Natural selection also favours altruism to those who might return the favour at a later
date (Axelrod, 1984; Trivers, 1971). Under some conditions – modelled by game theorists as
‘prisoner’s dilemmas’ – cooperation can be undermined by ‘cheats’, individuals who accept
the benefit of cooperation without paying the cost. In repeated interactions, a strategy of
‘conditional cooperation’ or ‘reciprocal altruism’ – which initiates and continues cooperation
with cooperators, but which detects and avoids (or punishes) cheats – can overcome this
‘free-rider’ problem (Ostrom & Walker, 2002). Surprisingly, few if any examples of full
blown ‘reciprocal altruism’ have been found in non-human species (Amici et al., 2014;
Clutton-Brock, 2009), although some aspects of reciprocity have been identified in cleaner
fish (Bshary & Grutter, 2006), vampire bats (Carter & Wilkinson, 2013), and primates
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(Mitani, 2009). However, it has been argued that reciprocal social exchange has been a
recurrent feature of the social lives of humans since our last common ancestors with
chimpanzees 6 million years ago (Jaeggi & Gurven, 2013); and there is some suggestive
evidence for trade between human groups from 82,000 years ago (Bouzouggar et al., 2007).
Humans appear to be equipped with adaptations for detecting (Cosmides & Tooby, 2005),
punishing (Price, Cosmides, & Tooby, 2002), and forgiving (McCullough, Kurzban, & Tabak,
2013) ‘cheats’. And reciprocity emerges early in children’s behaviour (Harbaugh, Krause,
Liday, & Vesterlund, 2002), and is used cross-culturally as a strategy for social exchange
(Henrich et al., 2005; Kocher, Cherry, Kroll, Netzer, & Sutter, 2008).
Thus, reciprocal altruism can explain kindness in the form of trust (initiating
cooperation), returning favours, gratitude (for favours yet to be returned), forgiveness and
friendship. The theory can also explain kindness to strangers. An altruistic act may be the
start of a beautiful friendship, a way of making a new friend (after all, ‘a stranger is just a
friend you haven’t met yet’). And in any case, it might be better to ‘err on the side of
caution’, and be altruistic just in case you happen to see the person again (Delton, Krasnow,
Cosmides, & Tooby, 2011; Krasnow, Delton, Tooby, & Cosmides, 2013).
The theory of reciprocal altruism predicts that these tendencies will most likely be
elicited in repeated interactions where individuals expect to meet again, where one’s
cooperative (or uncooperative) behaviour can be observed by others, and towards others who
have helped them in the past, or will be able to help them in the future (Kraft-Todd, Yoeli,
Bhanot, & Rand, 2015). For example, in an experimental game investigating donations made
in public to UNICEF, researchers found that those who gave more money away received
more from their fellow players (Milinski, Semmann, & Krambeck, 2002). And in a test of
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eight different messages designed to increase organ donation, an appeal to ‘reciprocity’ – “If
you needed an organ transplant, would you have one? If so, please help others” – was found
to be the most effective (Harper, 2013; see also: Sanders, Halpern, & Service, 2013, Trial 4).
People will be kind to others when it enhances their status
Natural selection can also favour altruism if it intimidates rivals or impresses potential
mates. Organisms often come into conflict over resources such as food, territory, and mates
(Huntingford & Turner, 1987). Although such conflicts appear purely competitive, in fact
there are costs involved in conflict – time, energy, and injury – that individuals have a
common interest in avoiding. One way of avoiding a damaging fight is for contestants to
display reliable indicators of “fighting ability” (“resource holding power”, or
“formidability”), and for the weaker party to cede the resource to the stronger. In this way, the
stronger party still wins, but both avoid the costs of a real fight (Maynard Smith & Price,
1973). Such ‘ritual contests’ are widespread in nature (C. W. Hardy & Briffa, 2013; Riechert,
1998). In stable social groups, in which relative ‘power’ is already known by reputation
(through direct experience or third-party observation), individuals can dispense with the
contest, and allocate disputed resources by ‘rank’. Such ‘dominance hierarchies’ represent a
further de-escalation of conflict, and are also widespread (Preuschoft & van Schaik, 2000).
Depending on the species, displays of size, weight, age, or experience may carry the day —
but displays of altruism can also work (Gintis, Smith, & Bowles, 2001; Zahavi & Zahavi,
1997). Humans and their recent ancestors have always faced the problem of resolving
conflict, because such problems are inherent in group living (Shultz & Dunbar, 2007). And
all human societies feature status hierarchies, which individuals (especially males) seek to
climb and derive satisfaction from climbing (Anderson, Hildreth, & Howland, 2015;
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Anderson, Kraus, Galinsky, & Keltner, 2012; Mazur, 2005). As predicted, humans –
especially males – commonly engage in costly and conspicuous displays of prowess,
resources, and even altruism (including generosity and bravery), especially in the context of
mate-competition (C. L. Hardy & Van Vugt, 2006; Hawkes, 1991; Hawkes, O'Connell, &
Blurton Jones, 2001; Mazur, 2005; Miller, 2000; Smith & Bleige Bird, 2000). Experiments
suggest that a tendency for the strong to display status by helping the weak – noblesse oblige
– is present cross-culturally (Fiddick, Cummins, Janicki, Lee, & Erlich, 2013).
Thus, ‘competitive altruism’ can explain kindness in the form of generosity, bravery,
heroism, chivalry, magnanimity and public service. This includes acts of kindness to
strangers. Helping a stranger may improve your status (Barclay, 2011; N. J. Raihani &
Bshary, 2015) whether the recipient is in a position to return the favour or not. And the theory
predicts that these tendencies will be elicited in the presence of rivals, or potential mates,
where acting altruistically may enhance one’s status. Consistent with this perspective,
research has shown that male donors give more when donating to an attractive female
fundraiser, especially in response to a large donation made by a competing male (Nichola J.
Raihani & Smith, 2015). (See also: Bereczkei, Birkas, & Kerekes, 2007; Iredale & Van Vugt,
2011).
Thus, multiple theories – kin altruism, mutualism, reciprocal altruism, competitive
altruism – explain multiple types of altruism, and multiple types of kindness. These theories
predict that people will be motivated to be kind to family, friends, colleagues, spouses, and
even strangers under some conditions. These same theories also predict that helping might
make people happy.
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The consequences of kindness
Why would helping make you happy? Broadly speaking, happiness (well-being,
pleasure) can be seen as an internal reward system for acting in ways that promote survival
and reproduction (Buss, 2000). Happiness is: “a psychological reward, an internal signaling
device that tells us that an adaptive problem has been, or is in the process of being, solved
successfully” (Hill, DelPriore, & Major, 2013). From this perspective, it is no problem to
explain why ‘eating’ or ‘having sex’ makes people happy; these behaviours meet important
adaptive goals. And, for the reasons outlined above, it is equally straightforward to explain
why performing acts of kindness might make people happy: it is because caring for family,
maintaining coalitions, trading favours and increasing status are also important adaptive
goals (Schulkin, 2011). Indeed, we might even expect helping others to produce more
happiness than helping yourself: it is precisely because helping others can sometimes give a
better return on investment than helping yourself that evolution has favoured kindness in the
first place.
Thus, the evolutionary behavioural science approach to altruism predicts that people
will be happy to help family, friends, community members, spouses, and even strangers under
some conditions. This prediction has received some support from the existing literature on 2
well-being. A large body of research has established an association between kindness and
happiness and health (Anik, Aknin, Norton, & Dunn, 2009; Konrath & Brown, 2013).
However, much of this research has been correlational — showing, for example, that people
who spend more money on others are happier (Lara B. Aknin et al., 2013), or people who
volunteer to help others are healthier (Jenkinson et al., 2013). While such correlational 3
evidence is consistent with the prediction that people will be happy to help others, it is not
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sufficient to establish a causal relationship between kindness and happiness. After all, it’s
possible that helping makes you happy; but it could also be that happiness makes you helpful,
or it could be that some third variable – health, income, or personality – makes you both
happy and helpful. The distinction between correlation and cause is not a mere philosophical
nicety; it is a genuine difference with important practical implications. In the absence of a
clear causal connection, kindness interventions may not work. They may waste time and
money, or displace other more effective interventions. Worse, they may be counter-
productive. If happiness causes helping (rather than the other way around), then forcing
unhappy people to help may make them less happy still.
In order to establish that performing acts of kindness can cause happiness, what is
needed is experimental research that randomly allocates participants to kindness and non-
kindness conditions, and then measures and compares their subsequent happiness. And so we
undertook a systematic review and meta-analysis of the experimental literature on the effects
of kindness interventions on well-being.
Methods
In order to identify suitable experimental studies of the effects of altruism on the
altruist's well-being, we conducted searches of the scientific databases Web of Science and
PsychInfo for academic articles. The most recent search was conducted on 1st September
2016. The process is summarised in the flow diagram in Figure 1. We used the search string:
(kindness OR altruis* OR prosocial OR co-operat* OR cooperat*) AND (wellbeing OR well-
being OR happiness OR life satisfaction) AND (experiment* OR control OR condition OR
random* OR empirical OR trial) NOT mindfulness OR meditation OR loving-kindness. This
search identified 639 articles. To this we added 19 articles identified by other means
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(following references in books and journal articles, Google scholar searches, viewing
academic researchers’ web-pages). After removing duplicates, we were left with 428 articles.
This initial set of 428 articles was screened. Two researchers (LAR and OSC) read the
titles and abstracts. Subsequently 380 articles were excluded for not meeting the inclusion
criteria. These articles were not experimental (that is, they were qualitative or correlational);
or the kindness-well-being effect was reversed (that is, they looked at whether making people
happy made them kinder, or whether kindness made the recipient happy or healthy); or they
were review papers presenting no new data; or they were on topics not directly relevant to the
current review and in which the effect of kindness on well-being was not measured (for
example, drug-alcohol rehabilitation programmes; kindness in animal husbandry; climate
change and planetary wellbeing; loving-kindness meditation/mindfulness). Cases in which
the researchers disagreed were given greater scrutiny and discussed, and where no consensus
was reached, the articles were included in the next stage of the analysis.
The remaining 48 articles were then read in full, and assessed for appropriateness for
the meta-analysis (see S2 for the full list). This process excluded a further 29 records (and
several studies from included articles) for reasons summarised in Table S1. At the end of this 4
process we were left with 19 articles, containing a total of 21 studies that had experimentally
tested the hypothesis that kindness causes well-being.
For each of these 21 studies we coded the following characteristics:
(a) theory of kindness being tested
(b) mean age of sample
(c) sex of participants
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(d) location of study
(e) type of altruist (for example, whether participants were ‘typically developed
individuals’, as opposed to having been diagnosed with some psychopathology)
(f) type of recipient (for example, whether family, friend, stranger)
(g) the nature of the intervention (for example, ‘random act of kindness’,
prosocial purchase, charitable donation)
(h) size of the intervention group
(i) nature of the control condition (for example, no treatment, self-kindness, other
activity)
(j) size of the control group
(k) dependent measure (for example, well-being, happiness, life-satisfaction)
(l) effect size (Cohen’s d)
When coding studies with multiple (control) groups, and / or multiple dependent
measures, we chose the most appropriate comparison (usually kindness versus neutral) and
the most appropriate measure (usually some measure of happiness).
Results
Study characteristics
The characteristics of the 21 studies are presented in Table 1. These 21 studies
included a total of 2,685 participants (~34% male, mean age ~25.49, SD=12.39). The 5
majority of participants came from Canada, USA and Europe, although there were also
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studies conducted in South Africa, Korea and Vanuatu. Most participants were university
students, although there were also two studies with children, one study of Vanuatu villagers,
and one with elderly participants.
The two most common interventions were ‘acts of kindness’ and ‘prosocial
purchasing’. Typical instructions for the ‘acts of kindness’ intervention were as follows:
“During the coming week, please perform at least five acts of kindness per day and report on them in the evening, including the responses of others that you received. Examples of acts of kindness are: holding a door for someone at university, greeting strangers in the hallway, helping other students in preparing for an exam, etcetera. It does not matter whether you address your acts of kindness to people you know or not” (Ouweneel, Le Blanc, & Schaufeli, 2014).
Prosocial purchasing interventions involved giving participants a sum of money, and
instructing them to spend it on someone else.
Most studies used a self-report measure of subjective well-being, happiness, life-
satisfaction, or positive and negative affect. These included the Subjective Happiness Scale
(SHS; S. Lyubomirsky & Lepper, 1999), the Steen Happiness Index (SHI; Seligman, Steen,
Park, & Peterson, 2005), the Satisfaction With Life Scale (SWLS; Diener, Emmons, Larsen,
& Griffin, 1985), and the Positive Affect and Negative Affect Scale (PANAS; Watson, Clark,
& Tellegen, 1988). Three studies used more objective measures: two used other-rated
smiling, and one used blood pressure.
Scrutiny of the 21 studies identified a number of methodological limitations. In two
studies, participants were not only not blind to the hypothesis, but were explicitly told that
performing acts of kindness would improve their mood (Nelson et al., 2015; Trew & Alden,
2015).
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There was also considerable variation in control conditions. Some studies compared
acting kindly with doing nothing (thus possibly confounding the effects of kindness with the
effects of performing any novel fun activity), whereas others compared acting kindly with
some other similarly interesting activity. (For a direct comparison of these two control
conditions, see: Buchanan & Bardi, 2010).
There was also considerable variation in whether the kindness intervention involved a
cost to the actor. Most ‘acts of kindness’ involved a cost; but, the ‘prosocial spending’ studies
that involved a windfall payment to the participant did not. It was not even clear that
spending the windfall on others even constituted an opportunity cost. In two studies, the
intervention involved either keeping or donating a children’s goody bag (consisting of
chocolate and juice) (Lara B. Aknin et al., 2013; L. B. Aknin, Fleerackers, & Hamlin, 2014).
For the adult participants in the study, keeping a child’s goody bag is presumably not much of
a benefit, and donating it not much of a cost.
We also note that many studies exhibited many ‘researcher degrees of
freedom’ (Simmons, Nelson, & Simonsohn, 2011), through the use of multiple dependent
measures; and that the results across these measures were not always consistent (for example,
the intervention would improve ‘positive affect’ but not ‘life satisfaction’, or vice versa).
Similarly, studies varied in duration, and were able to report results from multiple different
times, not all of which were consistent. For example “The kindness intervention had a
positive influence on both positive emotions and academic engagement, though not in the
long run” (Ouweneel et al., 2014).
However, in the interests of providing as broad an overview of the experimental
literature as possible we erred on the side of including these studies in the meta-analysis.
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Meta-analysis
Meta-analysis was conducted in SPSS V21 and R, following the recommendations
summarised in (Field & Gillett, 2010).
A random-effects model revealed that the mean effect size of the 21 studies was d = .
36, 95% confidence interval (CI) = [.26, .47], Z = 6.71, p < .001 (see Figure 2). This is a
small-to-medium effect, approximately equivalent to an increase of 0.8 on a standard 0-10
happiness scale (Helliwell, Layard, & Sachs, 2016).
A chi-square test of homogeneity of effect sizes was not significant, 2(19) 21.53, p=.
37. These measures suggest considerable similarity in effect sizes across studies. Consistent
with this finding, moderator analysis suggested that the effect of age or sex on the overall
effect size was not significant.
A file-drawer analysis, revealed that 595 unpublished, filed, or unretrieved studies
would be required to bring the significance of this average effect size to nonsignificance.
However, there was evidence of significant publication or reporting bias. Visual
inspection of the Funnel plots (Figure 3) suggests – and Begg's test τ(N = 21) = 0.32, p = 0.04
confirms – that smaller studies tended to find larger effects. This indicates that smaller studies
finding smaller (or negative) effects have not been submitted or published. Adjusting for
severe to moderate one-tailed selection suggests that the true effect size is likely to be 0.29 ≤
d ≤ 0.33 (Vevea & Woods, 2005).
Discussion
The results of this systematic review and meta-analysis of the experimental kindness
literature suggests that performing acts of kindness does improve the well-being of the actor.
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This finding is consistent with the claim that, as social animals, humans possess a range of
psychological mechanisms that motivate them to help others, and that they derive satisfaction
from doing so — in other words, that people are ‘happy to help’ family, friends, community
members, spouses, and even strangers under some conditions.
The effect of these kindness interventions is only small-to-medium (d ≤ 0.36).
However, this effect is comparable to other positive psychology interventions (d=0.34, Bolier
et al., 2013; d=0.31, Sin & Lyubomirsky, 2009; d=0.44, Weiss, Westerhof, & Bohlmeijer,
2016). Furthermore, we should keep in mind that this effect is an aggregate, averaged across 6
individuals and interventions across which theory suggests the effects of kindness
interventions may be very different.
First, theory suggests that some individuals will benefit more than others from
performing acts of kindness – that is, there will be individual differences in the degree to
which individuals derive satisfaction from helping. Like all personality traits (Polderman et
al., 2015), various different types of cooperative behaviours have been found to be
moderately heritable – including in-group favouritism (G. J. Lewis & Bates, 2010), trust
(Cesarini et al., 2008), and fairness (Wallace, Cesarini, Lichtenstein, & Johannesson, 2007).
The satisfaction derived from helping others, and establishing cooperative social relationships
is no exception (Haworth et al., 2016). In addition, there are also obvious situational and
contextual factors that should make a difference. Just as a hungry person derives more
pleasure from eating than a full person, we should expect individuals with a greater need or
desire to establish cooperative relationships to derive more satisfaction from being kind to
others. For example, lonely or isolated people — perhaps those who have moved to a new
city, or a new school — might be happier to seize opportunities to make new friends, or
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connect with their communities, than are people who ‘have enough friends already’ or who
are well-established in their communities. Ambitious people (with more resources to spare)
seeking status may have a greater appetite for, and be happier to seek, opportunities for
conspicuous altruism or public service — “You make a living by what you get; you make a
life by what you give” according to the quote often (mis)attributed to Winston Churchill. 7
Single people who are courting may be happier to help potential mates. Indeed, we might also
expect sex differences, with women happier to help children, and men happier to perform
chivalry or heroics.
However, because none of the studies has systematically varied the type of altruist
(the majority of participants were ‘typical’ although two studies focussed on ‘socially
anxious’ individuals), we do not know whether, for example, lonely people appreciate the
opportunity to reach out to others more than people whose ‘diaries are full’. We do not know
whether single people are happier performing romantic gestures than couples. We do not
know whether men and women are happier performing different types of kindness acts.
And so future research should also investigate whether performing acts of kindness
benefits some types of people more than others. Do people with a greater desire for social
connections benefit from being benevolent more than others? To what extent does sex, age
and income influence the satisfaction derived from acts of kindness? Do personality traits,
and social and moral values, play a mediating role? Do kindness interventions have a greater
effect on some mental health problems than others, perhaps those most related to social
interaction? And are kindness interventions particularly effective with people (re)integrating
into society after being absent from it – recent immigrants, ex-offenders, recovering addicts?
"20
HAPPY TO HELP
Second, theory also suggests that people will be happier to help some people more
than others — for example, family and friends as opposed to anonymous strangers. We note
that, in the present review, some of the studies with the largest effect sizes involved altruism
towards ‘friends and family’ (L. B. Aknin, Broesch, Hamlin, & Van de Vondervoort, 2015; L.
B. Aknin, Dunn, Whillans, Grant, & Norton, 2013; Geenen, Hoheluchter, Langholf, &
Walther, 2014); and other studies have shown that ‘social connection’ with the recipient
increases positive affect in the donor (L. Aknin, Dunn, Sandstrom, & Norton, 2013; L. B.
Aknin, Sandstrom, Dunn, & Norton, 2011). However, the studies reviewed here investigated
the effects of kindness ‘in general’; none systematically varied type of recipient, for example
family, colleague, friend, stranger. In fact, in most cases the recipient was left unspecified –
that is, they could be ‘anyone’. As a consequence, we do not know whether people are
happier giving to family and friends, as opposed to (anonymous) strangers. (And because no
study investigated the effects of acting at a cost to help an (anonymous) stranger, there is no
evidence (either way) on whether helping strangers makes you happy.) We do not know
whether people are happier giving to needy or unlucky recipients, as opposed to affluent or
lazy recipients. We do not know whether people are happier giving to children as opposed to
adults; in-group as opposed to out-groups; females as opposed to males. Thus future work
should seek to fill these gaps in our understanding. There is already a large literature on
whether people behave more or less altruistically to specific types of people; it would be
fairly straightforward to add measures of subjective well-being to replications and extensions
of these designs.
"21
HAPPY TO HELP
With the help of more precise theories regarding which altruists, and which recipients,
benefit most, future research should be able to identify the kind of kindness that works best,
and enable practitioners to ‘put their good where it will do the most’.
To that end, and in order to overcome the limitations of previous research, we make
the following recommendations for future research:
There is no scientific theory that predicts that humans will be selfish under all
conditions. Thus, repeatedly testing the folk intuition that people are selfish, and finding that
they are not, makes no contribution to science. Future research on the effects of kindness on
well-being should instead focus on developing and testing the more fine-grained predictions
of the numerous theories of altruism outlined above. Specifically, future research should
investigate whether the effects of kindness on the happiness of the actor depends on the type
of actor, the type of recipient, and the interaction of these two factors.
Future research could also seek to generalise these findings by employing more
representative community samples (including participants diagnosed with specific mental
health problems) and fewer college students, as well as conducting further cross-cultural
experiments (Henrich, Heine, & Norenzayan, 2010). Such research could harness the
unparalleled data collection opportunities provided by the internet, including on-line
fundraising platforms. And, given the predicted importance of non-anonymous, face-to-face
contact for cooperation and social relations, these internet methods should be combined with
field experiments to further generalise the finding, establish external validity, and pilot actual
interventions.
In addition, given that our meta-analysis suggests that the population effect may be as
low as d = 0.29, in order to detect such an effect with power β = 0.80, future researchers
"22
HAPPY TO HELP
should use a sample size of at least 188 per group (Faul, Erdfelder, Lang, & Buchner, 2007).
We note that only one of the studies reviewed in this meta-analysis met this criteria (average
group size = 64; average β = 0.41), and that such low-powered studies are likely to fail to
detect an effect even if it is there.
Future research could also investigate the effects of different types of altruism on the
recipient which, despite a couple of interesting studies, has yet to be systematically studied
(Baskerville et al., 2000; Pressman, Kraft, & Cross, 2015). For example, are people happier
to be helped by family, and friends as opposed to strangers? By in-group members as
opposed to out-group? Is there any element of shame or resentment at being a ‘charity case’?
Was Orwell right to argue that “A man receiving charity always hates his
benefactor” (Orwell, 1933). To what extent are people suspicious of the motives of altruistic
strangers?
Looking further ahead, future research should also consider the long-term
consequences of acts of kindness. Research on the ‘hedonic treadmill’ suggests that people
might have a hedonic ‘set point’ that they return to whatever happens to them, good or bad
(Ryan & Deci, 2001). So it’s possible that existing outcome measures, which tend to rely on
self-report well-being, are looking for effects in the wrong places (or at the wrong times).
Happiness is a quick hit, which rewards you now for doing things that have long-term
benefits in the future. So, rather than chasing the fleeting effects of happiness, it might be
better to employ or develop measures that assess those long-term benefits. If the function of
altruistic behaviour is to help families, improve communities, make new friends, find a mate,
or increase status, then studies should be measuring these outcomes. Do people allocated to
the kindness condition report better relations with their families? More identification with
"23
HAPPY TO HELP
their communities? More friends? More sexual partners (Arnocky, Piché, Albert, Ouellette, &
Barclay, 2016)? More committed relationships (Kogan et al., 2010)? More resilient
marriages? More recognition and honours? More pride in one’s achievements (Sznycer et al.,
in press)? If so, then future research might be able to finally connect the two types of
happiness — hedonic and eudaemonic — that have hitherto remained apart.
Conclusion
Helping others makes you happy, but the effect is relatively modest. Further empirical
work testing the implications of the many existing theories of social, cooperative and
altruistic behaviour is need to determine whether the effect might be larger for some types of
helpers, when helping some types of recipients. This research will advance our understanding
of the causes and consequences of kindness, and help practitioners to maximise the
effectiveness of kindness interventions.
"24
HAPPY TO HELP
Bibliography
Adams, W. C. (1986). Whose Lives Count? TV Coverage of Natural Disasters. Journal of
Communication, 36(2), 113-122. doi:10.1111/j.1460-2466.1986.tb01429.x
Aked, J., Marks, N., Cordon, C., & Thompson, S. (2008). Five Ways to Wellbeing: The
Evidence. Retrieved from http://www.neweconomics.org/publications/entry/five-
ways-to-well-being-the-evidence
Aked, J., & Thompson, S. (2011). Five Ways to Wellbeing: New applications, new ways of
thinking. Retrieved from http://www.neweconomics.org/publications/entry/well-
being-evidence-for-policy-a-review
Aknin, L., Dunn, E., Sandstrom, G., & Norton, M. (2013). Does social connection turn good
deeds into good feelings?
Aknin, L. B., Barrington-Leigh, C. P., Dunn, E. W., Helliwell, J. F., Burns, J., Biswas-Diener,
R., . . . Norton, M. I. (2013). Prosocial spending and well-being: Cross-cultural
evidence for a psychological universal. Journal of Personality and Social PSychology,
104(4), 635-652. doi:10.1037/a0031578
Aknin, L. B., Broesch, T., Hamlin, J. K., & Van de Vondervoort, J. W. (2015). Prosocial
Behavior Leads to Happiness in a Small-Scale Rural Society. Journal of Experimental
Psychology-General, 144(4), 788-795. doi:10.1037/xge0000082
Aknin, L. B., Dunn, E. W., Whillans, A. V., Grant, A. M., & Norton, M. I. (2013). Making a
difference matters: Impact unlocks the emotional benefits of prosocial spending.
Journal of Economic Behavior & Organization, 88, 90-95. doi:10.1016/j.jebo.
2013.01.008
"25
HAPPY TO HELP
Aknin, L. B., Fleerackers, A. L., & Hamlin, J. K. (2014). Can third-party observers detect the
emotional rewards of generous spending? Journal of Positive Psychology, 9(3),
198-203. doi:10.1080/17439760.2014.888578
Aknin, L. B., Sandstrom, G. M., Dunn, E. W., & Norton, M. I. (2011). It's the Recipient That
Counts: Spending Money on Strong Social Ties Leads to Greater Happiness than
Spending on Weak Social Ties. Plos One, 6(2). doi:10.1371/journal.pone.0017018
Alvard, M. (2001). Mutualistic Hunting. In C. Stanford & H. Bunn (Eds.), Meat-Eating and
Human Evolution (pp. 261-278). New York: Oxford University Press.
Alvard, M., & Nolin, D. (2002). Rousseau’s whale hunt? Current Anthropology, 43(4),
533-559.
Amici, F., Aureli, F., Mundry, R., Amaro, A., Barroso, A., Ferretti, J., & Call, J. (2014).
Calculated reciprocity? A comparative test with six primate species. Primates, 55(3),
447-457. doi:10.1007/s10329-014-0424-4
Anderson, C., Hildreth, J. A. D., & Howland, L. (2015). Is the desire for status a fundamental
human motive? A review of the empirical literature. Psychological Bulletin, 141(3),
574-601. doi:10.1037/a0038781
Anderson, C., Kraus, M. W., Galinsky, A. D., & Keltner, D. (2012). The local-ladder effect:
social status and subjective well-being. Psychological Science, 23(7), 764-771. doi:
10.1177/0956797611434537
Anik, L., Aknin, L. B., Norton, M. I., & Dunn, E. W. (2009). Feeling Good about Giving: The
Benefits (and Costs) of Self-Interested Charitable Behavior - HBS Working
Knowledge - Harvard Business School.
"26
HAPPY TO HELP
Arnocky, S., Piché, T., Albert, G., Ouellette, D., & Barclay, P. (2016). Altruism predicts
mating success in humans. British Journal of Psychology. doi:10.1111/bjop.12208
Axelrod, R. (1984). The Evolution of Cooperation. New York: Basic Books.
Balliet, D., Wu, J., & De Dreu, C. K. W. (2014). Ingroup Favoritism in Cooperation: A Meta-
Analysis. Psychological Bulletin, No Pagination Specified. doi:10.1037/a0037737
Barclay, P. (2011). The evolution of charitable behaviour and the power of reputation. In S. C.
Roberts (Ed.), Applied Evolutionary Psychology. Oxford: Oxford University Press.
Baskerville, K., Johnson, K., Monk-Turner, E., Slone, Q., Standley, H., Stansbury, S., . . .
Young, J. (2000). Reactions to random acts of kindness2. The Social Science Journal,
37(2), 293-298. doi:http://dx.doi.org/10.1016/S0362-3319(00)00062-8
Bereczkei, T., Birkas, B., & Kerekes, Z. (2007). Public charity offer as a proximate factor of
evolved reputation-building strategy: an experimental analysis of a real-life situation.
Evolution And Human Behavior, 28(4), 277-284. doi:http://dx.doi.org/10.1016/
j.evolhumbehav.2007.04.002
Bernhard, H., Fischbacher, U., & Fehr, E. (2006). Parochial altruism in humans. Nature,
442(7105), 912-915. doi:Doi 10.1038/Nature04981
Bissonnette, A., Perry, S., Barrett, L., Mitani, J. C., Flinn, M., Gavrilets, S., & de Waal, F. B.
M. (2015). Coalitions in theory and reality: a review of pertinent variables and
processes. Behaviour, 152(1), 1-56. doi:doi:10.1163/1568539X-00003241
Boinski, S., & Garber, P. A. (Eds.). (2000). On the Move: How and Why Animals Travel in
Groups: Chicago University Press.
"27
HAPPY TO HELP
Bolier, L., Haverman, M., Westerhof, G. J., Riper, H., Smit, F., & Bohlmeijer, E. (2013).
Positive psychology interventions: a meta-analysis of randomized controlled studies.
BMC Public Health, 13(1), 1-20. doi:10.1186/1471-2458-13-119
Boos, M., Kolbe, M., Kappeler, P. M., & Ellwart, T. (Eds.). (2011). Coordination in Human
and Primate Groups: Springer.
Bouzouggar, A., Barton, N., Vanhaeren, M., d'Errico, F., Collcutt, S., Higham, T., . . .
Stambouli, A. (2007). 82,000-year-old shell beads from North Africa and implications
for the origins of modern human behavior. Proceedings of the National Academy of
Sciences, 104(24), 9964-9969. doi:10.1073/pnas.0703877104
Bshary, R., & Grutter, A. S. (2006). Image scoring and cooperation in a cleaner fish
mutualism. Nature, 441(7096), 975-978. doi:http://www.nature.com/nature/journal/
v441/n7096/suppinfo/nature04755_S1.html
Buchanan, K. E., & Bardi, A. (2010). Acts of Kindness and Acts of Novelty Affect Life
Satisfaction. The Journal of Social Psychology, 150(3), 235-237. doi:
10.1080/00224540903365554
Burt, C. D., & Strongman, K. (2005). Use of images in charity advertising: Improving
donations and compliance rates. International Journal of Organisational Behaviour,
8(8), 571-580.
Buss, D. M. (2000). The Evolution of Happiness. American Psychologist, 55(1), 15-23.
Carter, G. G., & Wilkinson, G. S. (2013). Food sharing in vampire bats: reciprocal help
predicts donations more than relatedness or harassment. Proceedings of the Royal
Society B: Biological Sciences, 280(1753). doi:10.1098/rspb.2012.2573
"28
HAPPY TO HELP
Cesarini, D., Dawes, C. T., Fowler, J. H., Johannesson, M., Lichtenstein, P., & Wallace, B.
(2008). Heritability of cooperative behavior in the trust game. PNAS, 105, 3721-3726.
Chapais, B. (2014). Complex Kinship Patterns as Evolutionary Constructions, and the
Origins of Sociocultural Universals. Current Anthropology, 55(6), 751-783. doi:
10.1086/678972
Clutton-Brock, T. H. (1991). The Evolution of Parental Care. Pinceton, NJ: Princeton
University Press.
Clutton-Brock, T. H. (2009). Cooperation between non-kin in animal societies. Nature, 462,
51-57.
Cosmides, L., & Tooby, J. (2005). Neurocognitive adaptations designed for social exchange.
In D. M. Buss (Ed.), The Handbook of Evolutionary Psychology (pp. 584-627). NY:
Wiley.
Coyne, J. C. (2014a). Failing grade for highly cited meta-analysis of positive psychology
interventions. Retrieved from http://blogs.plos.org/mindthebrain/2014/11/18/failing-
grade-highly-cited-meta-analysis-positive-psychology-interventions/
Coyne, J. C. (2014b). Positive psychology interventions for depressive symptoms. Retrieved
from http://blogs.plos.org/mindthebrain/2014/10/28/positive-psychology-
interventions-depressive-symptoms/
Curry, O. S. (2016). Morality as Cooperation: A Problem-Centred Approach. In T. K.
Shackelford & R. D. Hansen (Eds.), The Evolution of Morality (pp. 27-51): Springer
International Publishing.
"29
HAPPY TO HELP
Curry, O. S., Roberts, S. G. B., & Dunbar, R. I. M. (2013). Altruism in social networks:
Evidence for a ‘kinship premium’. British Journal of Psychology, 104(2), 283-295.
doi:10.1111/j.2044-8295.2012.02119.x
Daly, M., & Wilson, M. (1996). Violence against stepchildren. Current Directions in
Psychological Science, 5(77-81).
Dawkins, R. (1979). Twelve Misunderstandings of Kin Selection. Zeitschrift für
Tierpsychologie, 51(2), 184-200. doi:10.1111/j.1439-0310.1979.tb00682.x
DeBruine, L. M. (2005). Trustworthy but not lust-worthy: Context-specific effects of facial
resemblance. Proceedings of the Royal Society of London B., 272, 919-922.
Delton, A. W., Krasnow, M. M., Cosmides, L., & Tooby, J. (2011). Evolution of direct
reciprocity under uncertainty can explain human generosity in one-shot encounters.
Proceedings of the National Academy of Sciences of the United States of America,
108(32), 13335-13340. doi:10.1073/pnas.1102131108
Diener, E., Emmons, R. A., Larsen, R. J., & Griffin, S. (1985). The Satisfaction with Life
Scale. Journal of Personality Assessment, 49(1), 71-75. doi:DOI 10.1207/
s15327752jpa4901_13
Dolan, P., & Metcalfe, R. (2012). Measuring Subjective Wellbeing: Recommendations on
Measures for use by National Governments. Journal of Social Policy, 41, 409-427.
doi:10.1017/S0047279411000833
Euler, H. A., & Weitzel, B. (1996). Discriminative grandparental solicitude as reproductive
strategy. Human Nature, 7, 39-59.
"30
HAPPY TO HELP
Faul, F., Erdfelder, E., Lang, A.-G., & Buchner, A. (2007). G*Power 3: A flexible statistical
power analysis program for the social, behavioral, and biomedical sciences. Behavior
Research Methods, 39(2), 175-191. doi:10.3758/bf03193146
Fiddick, L., Cummins, D., Janicki, M., Lee, S., & Erlich, N. (2013). A Cross-Cultural Study
of Noblesse Oblige in Economic Decision-Making. Human Nature, 24(3), 318-335.
doi:10.1007/s12110-013-9169-9
Field, A. P., & Gillett, R. (2010). How to do a meta-analysis. British Journal of Mathematical
and Statistical Psychology, 63(3), 665-694. doi:10.1348/000711010X502733
Gardner, A., & West, S. A. (2014). Special issue: Inclusive fitness; 50 years on. Philosophical
Transactions of the Royal Society B: Biological Sciences, 369.
Geary, D. C., & Flinn, M. V. (2001). Evolution of Human Parental Behavior and the Human
Family. Parenting-Science and Practice, 1(1-2), 5-61. doi:Pii 785828753
10.1207/S15327922par011&2_2
Geenen, N. Y. R., Hoheluchter, M., Langholf, V., & Walther, E. (2014). The beneficial effects
of prosocial spending on happiness: work hard, make money, and spend it on others?
Journal of Positive Psychology, 9(3), 204-208. doi:10.1080/17439760.2014.891154
Gintis, H., Smith, E. A., & Bowles, S. (2001). Costly signaling and cooperation. Journal of
Theoretical Biology, 213, 103-119. doi:10.1006/jtbi.2001.2406
Hamilton, W. D. (1964). The genetical evolution of social behaviour. Journal of Theoretical
Biology, 7, 1-16, 17-52. doi:10.1016/0022-5193(64)90039-6
Hammerstein, P. (Ed.) (2003). Genetic and Cultural Evolution of Cooperation. Cambridge,
Mass: MIT Press.
"31
HAPPY TO HELP
Harbaugh, W. T., Krause, K., Liday, S. G., & Vesterlund, L. (2002). Trust in Children. In E.
Ostrom & J. Walker (Eds.), Trust, Reciprocity and Gains from Association:
Interdisciplinary Lessons from Experimental Research (pp. 302-322). New York:
Russell Sage Foundation.
Harcourt, A., & de Waal, F. B. M. (Eds.). (1992). Coalitions and Alliances in Humans and
Other Animals. Oxford: Oxford University Press.
Hardy, C. L., & Van Vugt, M. (2006). Nice Guys Finish First: The Competitive Altruism
Hypothesis. Personality and Social Psychology Bulletin, 32(10), 1402-1413. doi:
10.1177/0146167206291006
Hardy, C. W., & Briffa, M. (Eds.). (2013). Animal contests. Cambridge: Cambridge
University Press.
Harper, H. (2013). Applying Behavioural Insights to Organ Donation: preliminary results
from a randomised controlled trial. Retrieved from http://
www.behaviouralinsights.co.uk/publications/applying-behavioural-insights-to-organ-
donation/
Hawkes, K. (1991). Showing off: tests of another hypothesis about men’s foraging goals.
Ethology and Sociobiology, 12(1), 29-54.
Hawkes, K., O'Connell, J. F., & Blurton Jones, N. G. (2001). Hadza meat sharing. Evolution
and Human Behavior, 22(2), 113-142.
Haworth, C. M. A., Nelson, S. K., Layous, K., Carter, K., Jacobs Bao, K., Lyubomirsky, S., &
Plomin, R. (2016). Stability and Change in Genetic and Environmental Influences on
"32
HAPPY TO HELP
Well-Being in Response to an Intervention. PLoS ONE, 11(5), e0155538. doi:
10.1371/journal.pone.0155538
Helliwell, J., Layard, R., & Sachs, J. (2016). World Happiness Report 2016 Update.
Retrieved from New York: http://worldhappiness.report
Henrich, J., Boyd, R., Bowles, S., Camerer, C., Fehr, E., Gintis, H., . . . Tracer, D. (2005).
'Economic Man' in Cross-cultural Perspective: Behavioral experiments in 15 small-
scale societies. Behavioral and Brain Sciences, 28(6), 795–855.
Henrich, J., Heine, S. J., & Norenzayan, A. (2010). Beyond WEIRD: Towards a broad-based
behavioral science. Behavioral and Brain Sciences, 33(2-3), 111-135. doi:10.1017/
S0140525x10000725
Hill, S. E., DelPriore, D. J., & Major, B. (2013). An Evolutionary Psychological Perspective
on Happiness. In I. Boniwell, S. A. David, & A. C. Ayers (Eds.), Oxford Handbook of
Happiness.
Hublin, J.-J. (2009). The prehistory of compassion. Proceedings of the National Academy of
Sciences, 106(16), 6429-6430. doi:10.1073/pnas.0902614106
Huntingford, F. A., & Turner, A. K. (1987). Animal Conflict. London & New York: Chapman
and Hall.
Huppert, F. A. (2009). Psychological Well-being: Evidence Regarding its Causes and
Consequences†. Applied Psychology: Health and Well-Being, 1(2), 137-164. doi:
10.1111/j.1758-0854.2009.01008.x
"33
HAPPY TO HELP
Iredale, W., & Van Vugt, M. (2011). Altruism as showing off: a signalling perspective on
promoting green behaviour and acts of kindness. In S. C. Roberts (Ed.), Applied
Evolutionary Psychology. Oxford: Oxford University Press.
Jaeggi, A. V., & Gurven, M. (2013). Reciprocity explains food sharing in humans and other
primates independent of kin selection and tolerated scrounging: a phylogenetic meta-
analysis. Proceedings of the Royal Society of London B: Biological Sciences,
280(1768).
Jenkinson, C. E., Dickens, A. P., Jones, K., Thompson-Coon, J., Taylor, R. S., Rogers, M., . . .
Richards, S. H. (2013). Is volunteering a public health intervention? A systematic
review and meta-analysis of the health and survival of volunteers. BMC Public
Health, 13(1), 1-10. doi:10.1186/1471-2458-13-773
Kocher, M. G., Cherry, T., Kroll, S., Netzer, R. J., & Sutter, M. (2008). Conditional
cooperation on three continents. Economics Letters, 101, 175-178. doi:10.1016/
j.econlet.2008.07.015,
Kogan, A., Impett, E. A., Oveis, C., Hui, B., Gordon, A. M., & Keltner, D. (2010). When
Giving Feels Good: The Intrinsic Benefits of Sacrifice in Romantic Relationships for
the Communally Motivated. Psychological Science, 21(12), 1918-1924. doi:
10.1177/0956797610388815
Konrath, S., & Brown, S. (2013). The effects of giving on givers. In M. L. Newman & N. A.
Roberts (Eds.), Health and social relationships: The good, the bad, and the
complicated. (pp. 39-64). Washington: American Psychological Association.
"34
HAPPY TO HELP
Kraft-Todd, G., Yoeli, E., Bhanot, S., & Rand, D. (2015). Promoting cooperation in the field.
Current Opinion in Behavioral Sciences, 3, 96-101. doi:http://dx.doi.org/10.1016/
j.cobeha.2015.02.006
Krasnow, M. M., Delton, A. W., Tooby, J., & Cosmides, L. (2013). Meeting now suggests we
will meet again: Implications for debates on the evolution of cooperation. Sci. Rep., 3.
doi:10.1038/srep01747
Kurzban, R., Tooby, J., & Cosmides, L. (2001). Can race be erased? Coalitional computation
and social categorization. Proceedings of the National Academy of Sciences of the
United States of America, 98(26), 15387-15392.
Laura Stoll, J. M. a. C. S. (2011). Well-being evidence for policy: A review. Retrieved from
http://www.neweconomics.org/publications/entry/well-being-evidence-for-policy-a-
review
Lehmann, L., & Keller, L. (2006). The evolution of cooperation and altruism – a general
framework and a classification of models. Journal of Evolutionary Biology, 19(5),
1365-1376. doi:10.1111/j.1420-9101.2006.01119.x
Lewis, D. K. (1969). Convention: a philosophical study. Cambridge, Massachusetts: Harvard
University Press.
Lewis, G. J., & Bates, T. C. (2010). Genetic Evidence for Multiple Biological Mechanisms
Underlying In-Group Favoritism. Psychological Science, 21(11), 1623-1628. doi:Doi
10.1177/0956797610387439
Lieberman, D., Tooby, J., & Cosmides, L. (2003). Does morality have a biological basis? An
empirical test of the factors governing moral sentiments relating to incest.
"35
HAPPY TO HELP
Proceedings of the Royal Society of London Series B-Biological Sciences, 270(1517),
819-826. doi:Doi 10.1098/Rspb.2002.2290
Lieberman, D., Tooby, J., & Cosmides, L. (2007). The architecture of human kin detection.
Nature, 445(7129), 727-731. doi:10.1038/Nature05510
Lyubomirsky, S., & Lepper, H. S. (1999). A measure of subjective happiness: Preliminary
reliability and construct validation. Social Indicators Research, 46(2), 137-155.
doi:Doi 10.1023/A:1006824100041
Lyubomirsky, S., Sheldon, K. M., & Schkade, D. (2005). Pursuing happiness: The
architecture of sustainable change. Review of General Psychology, 9(2), 111-131. doi:
10.1037/1089-2680.9.2.111
Madsen, E. A., Tunney, R. J., Fieldman, G., Plotkin, H. C., Dunbar, R. I. M., Richardson, J.-
M., & McFarland, D. (2007). Kinship and altruism: A cross-cultural experimental
study. British Journal of Psychology, 98(2), 339-359. doi:
10.1348/000712606X129213
Mateo, J. M. (2015). Perspectives: Hamilton's Legacy: Mechanisms of Kin Recognition in
Humans. Ethology : formerly Zeitschrift fur Tierpsychologie, 121(5), 419-427. doi:
10.1111/eth.12358
Maynard Smith, J., & Price, G. R. (1973). The logic of animal conflict. Nature, 246, 15-18.
Mazur, A. (2005). Biosociology of Dominance and Deference. Lanham, Maryland: Rowan &
Littlefield.
"36
HAPPY TO HELP
McCullough, M. E., Kurzban, R., & Tabak, B. A. (2013). Cognitive systems for revenge and
forgiveness. Behavioral and Brain Sciences, 36(01), 1-15. doi:doi:10.1017/
S0140525X11002160
McElreath, R., Boyd, R., & Richerson, P. J. (2003). Shared norms and the evolution of ethnic
markers. Current Anthropology, 44(1), 122-129.
Milinski, M., Semmann, D., & Krambeck, H. J. (2002). Donors to charity gain in both
indirect reciprocity and political reputation. Proceedings Of The Royal Society B-
Biological Sciences, 269(1494), 881-883. doi:10.1098/rspb.2002.1964
Miller, G. F. (2000). The Mating Mind. London: William Heinemann.
Mitani, J. C. (2009). Cooperation and Competition in Chimpanzees: Current Understanding
and Future Challenges. Evolutionary Anthropology, 18(5), 215-227. doi:Doi 10.1002/
Evan.20229
Nelson, S. K., Della Porta, M. D., Bao, K. J., Lee, H. C., Choi, I., & Lyubomirsky, S. (2015).
'It's up to you': Experimentally manipulated autonomy support for prosocial behavior
improves well-being in two cultures over six weeks. Journal of Positive Psychology,
10(5), 463-476. doi:10.1080/17439760.2014.983959
Nunn, C. L., & Lewis, R. J. (2001). Cooperation and collective action in animal behaviour
Economics in Nature: Social Dilemmas, mate choice and biological markets (pp.
42-66). Cambridge: CUP.
OECD. (2013). OECD Guidelines on Measuring Subjective Well-being: OECD Publishing.
Orwell, G. (1933). Down and Out in Paris and London. London: Victor Gollancz.
"37
HAPPY TO HELP
Ostrom, L., & Walker, J. (Eds.). (2002). Trust and Reciprocity: Interdisciplinary lessons from
experimental research. New York: Russell Sage Foundation.
Ouweneel, E., Le Blanc, P. M., & Schaufeli, W. B. (2014). On Being Grateful and Kind:
Results of Two Randomized Controlled Trials on Study-Related Emotions and
Academic Engagement. The Journal of Psychology, 148(1), 37-60. doi:
10.1080/00223980.2012.742854
Pavey, L., Greitemeyer, T., & Sparks, P. (2011). Highlighting Relatedness Promotes Prosocial
Motives and Behavior. Personality and Social Psychology Bulletin, 37(7), 905-917.
doi:10.1177/0146167211405994
Pietraszewski, D., Curry, O. S., Petersen, M. B., Cosmides, L., & Tooby, J. (2015).
Constituents of political cognition: Race, party politics, and the alliance detection
system. Cognition, 140(0), 24-39. doi:http://dx.doi.org/10.1016/j.cognition.
2015.03.007
Platek, S. M., Burch, R. L., Panyavin, I. S., Wasserman, B. H., & Gallup Jr, G. G. (2002).
Reactions to children’s faces: Resemblance affects males more than females.
Evolution And Human Behavior, 23, 159-166.
Polderman, T. J. C., Benyamin, B., de Leeuw, C. A., Sullivan, P. F., van Bochoven, A.,
Visscher, P. M., & Posthuma, D. (2015). Meta-analysis of the heritability of human
traits based on fifty years of twin studies. Nat Genet, 47(7), 702-709. doi:10.1038/ng.
3285 http://www.nature.com/ng/journal/v47/n7/abs/ng.3285.html#supplementary-
information
"38
HAPPY TO HELP
Pressman, S. D., Kraft, T. L., & Cross, M. P. (2015). It’s good to do good and receive good:
The impact of a ‘pay it forward’ style kindness intervention on giver and receiver
well-being. The Journal of Positive Psychology, 10(4), 293-302. doi:
10.1080/17439760.2014.965269
Preston, S. D., & de Waal, F. B. M. (2002). Empathy: Its ultimate and proximate bases.
Behavioral and Brain Sciences, 25, 1-72.
Preuschoft, S., & van Schaik, C. P. (2000). Dominance and Communication: Conflict
management in various social settings. In F. Aureli & F. B. M. de Waal (Eds.), Natural
conflict resolution (pp. 77-105). Berkeley: University of California Press.
Price, M. E., Cosmides, L., & Tooby, J. (2002). Punitive sentiment as an anti-free rider
psychological device. Evolution and Human Behavior, 23(3), 203-231. doi:10.1016/
j.evolhumbehav.2004.08.009
Raihani, N. J., & Bshary, R. (2015). Why humans might help strangers. Frontiers in
Behavioral Neuroscience, 9(39). doi:10.3389/fnbeh.2015.00039
Raihani, Nichola J., & Smith, S. (2015). Competitive Helping in Online Giving. Current
Biology, 25(9), 1183-1186. doi:10.1016/j.cub.2015.02.042
Riechert, S. E. (1998). Game theory and animal contests. In L. A. Dugatkin & H. K. Reeve
(Eds.), Game Theory and Animal Behavior (pp. pp64-93). Oxford: Oxford University
Press.
Royle, N. J., Smiseth, P. T., & Kölliker, M. (Eds.). (2012). The Evolution of Parental Care:
OUP.
"39
HAPPY TO HELP
Ryan, R. M., & Deci, E. L. (2001). On happiness and human potentials: a review of research
on hedonic and eudaimonic well-being. Annual Review of Psychology, 52, 141-166.
doi:10.1146/annurev.psych.52.1.141
Sachs, J. L., Mueller, U. G., Wilcox, T. P., & Bull, J. J. (2004). The Evolution of Cooperation.
The Quarterly Review of Biology, 79(2), 135-160. doi:10.1086/383541
Sanders, M., Halpern, D., & Service, O. (2013). Applying behavioural insights to charitable
giving. Retrieved from https://www.gov.uk/government/publications/applying-
behavioural-insights-to-charitable-giving
Schelling, T. C. (1960). The Strategy of Conflict. Cambridge, Massachusetts: Harvard
University Press.
Schulkin, J. (2011). Adaptation and Well-Being: Social Allostasis: Cambridge University
Press.
Seligman, M. E. P., Steen, T. A., Park, N., & Peterson, C. (2005). Positive psychology
progress - Empirical validation of interventions. American Psychologist, 60(5),
410-421. doi:10.1037/0003-066x.60.5.410
Sherif, M., Harvey, O. J., White, B. J., Hood, W. R., & Sherif, C. W. (1954/1961). Intergroup
Conflict and Cooperation: The Robbers Cave Experiment. Norman: University of
Oklahoma Book Exchange.
Shultz, S., & Dunbar, R. I. M. (2007). The evolution of the social brain: anthropoid primates
contrast with other vertebrates. Proceedings of the Royal Society of London B:
Biological Sciences, 274(1624), 2429-2436.
"40
HAPPY TO HELP
Shultz, S., Opie, C., & Atkinson, Q. D. (2011). Stepwise evolution of stable sociality in
primates. Nature, 479(7372), 219-222. doi:http://www.nature.com/nature/journal/
v479/n7372/abs/nature10601.html#supplementary-information
Simmons, J. P., Nelson, L. D., & Simonsohn, U. (2011). False-Positive Psychology:
Undisclosed Flexibility in Data Collection and Analysis Allows Presenting Anything
as Significant. Psychological Science, 22(11), 1359-1366. doi:
10.1177/0956797611417632
Sin, N. L., & Lyubomirsky, S. (2009). Enhancing well-being and alleviating depressive
symptoms with positive psychology interventions: a practice-friendly meta-analysis.
Journal of Clinical Psychology, 65(5), 467-487. doi:10.1002/jclp.20593
Skyrms, B. (2004). The Stag Hunt and the Evolution of Social Structure. Cambridge:
Cambridge University Press.
Small, D. A., & Verrochi, N. M. (2009). The Face of Need: Facial Emotion Expression on
Charity Advertisements. Journal of Marketing Research, 46(6), 777-787.
Smith, E. A., & Bleige Bird, R. L. (2000). Turtle hunting and tombstone opening: public
generosity as costly signaling. Evolution And Human Behavior, 21, 245-261.
Sznycer, D., Al-Shawaf, L., Bereby-Meyer, Y., Curry, O. S., Smet, D. D., Ermer, E., . . .
Tooby, J. (in press). Cross-cultural regularities in the cognitive architecture of pride.
PNAS.
Tajfel, H. (1970). Experiments in intergroup discrimination. Scientific American, 223(5),
96-102.
"41
HAPPY TO HELP
Tomasello, M., Carpenter, M., Call, J., Behne, T., & Moll, H. (2005). Understanding and
sharing intentions: The origins of cultural cognition. Behavioral and Brain Sciences,
28(5), 675-+.
Tooby, J., & Cosmides, L. (2010). Groups in Mind: The Coalitional Roots of War and
Morality (pp. 191-234).
Tooby, J., & DeVore, I. (1987). The reconstruction of hominid behavioral evolution through
strategic modeling. In W. G. Kinzey (Ed.), The Evolution of Human Behavior:
Primate models (pp. 183-237). Albany, New York: SUNY Press.
Trew, J. L., & Alden, L. E. (2015). Kindness reduces avoidance goals in socially anxious
individuals. Motivation and Emotion, 39(6), 892-907. doi:10.1007/
s11031-015-9499-5
Trivers, R. L. (1971). The evolution of reciprocal altruism. Quarterly Review of Biology,
46(1), 35-57. doi:10.1086/406755
Vevea, J. L., & Woods, C. M. (2005). Publication Bias in Research Synthesis: Sensitivity
Analysis Using A Priori Weight Functions. Psychological Methods, 10(4), 428-443.
doi:10.1037/1082-989X.10.4.428
Walker, R. S. (2014). Amazonian horticulturalists live in larger, more related groups than
hunter–gatherers. Evolution And Human Behavior, 35(5), 384-388. doi:http://
dx.doi.org/10.1016/j.evolhumbehav.2014.05.003
Wallace, B., Cesarini, D., Lichtenstein, P., & Johannesson, M. (2007). Heritability of
ultimatum game responder behavior. Proceedings of the National Academy of
Sciences, 10(1073).
"42
HAPPY TO HELP
Watson, D., Clark, L. A., & Tellegen, A. (1988). Development and Validation of Brief
Measures of Positive and Negative Affect - the Panas Scales. Journal of Personality
and Social PSychology, 54(6), 1063-1070. doi:Doi 10.1037/0022-3514.54.6.1063
Weiss, L. A., Westerhof, G. J., & Bohlmeijer, E. T. (2016). Can We Increase Psychological
Well-Being? The Effects of Interventions on Psychological Well-Being: A Meta-
Analysis of Randomized Controlled Trials. PLoS ONE, 11(6), e0158092. doi:10.1371/
journal.pone.0158092
Whitehouse, H., & Lanman, J. A. (2014). The Ties That Bind Us Ritual, Fusion, and
Identification. Current Anthropology, 55(6), 674-695. doi:10.1086/678698
Wrangham, R. (1999). Evolution of Coalitionary Killing. Yearbook of Physical Anthropology,
42, 1-30.
Young, L., Camprodon, J. A., Hauser, M., Pascual-Leone, A., & Saxe, R. (2010). Disruption
of the right temporoparietal junction with transcranial magnetic stimulation reduces
the role of beliefs in moral judgments. Proceedings of the National Academy of
Sciences of the United States of America, 107(15), 6753-6758.
Zahavi, A., & Zahavi, A. (1997). The Handicap Principle: A missing piece of Darwin’s
puzzle. Oxford: Oxford Univerity Press.
"43
HAPPY TO HELP
Endnotes
Rather than attempting to force these diverse theories, mechanisms and processes into a single definition, for 1
the remainder of this paper we will use kindness, altruism, helping, prosociality and related terms interchangeably, to refer broadly to actions that benefit others (at a cost to self), usually accompanied by benevolent subjective emotions.
Given that ‘well-being’ encapsulates a range of states and associated behaviours (OECD, 2013), and is 2
generally "measured by simply asking people about their happiness” (Dolan & Metcalfe, 2012), for the remainder of this paper we will use well-being, happiness, life-satisfaction and related terms interchangeably.
Even then the effects are modest. This meta-analysis of the relationship between volunteering and health in the 3
elderly found that volunteers were 22% less likely that non-volunteers to die during the follow-up period of the studies (Jenkinson et al., 2013). However, the import of this finding depends on the base-rate. By way of illustration, if on average 10 out of 1000 (1%) non-volunteers die during the follow-up period, then a 22% percent decrease means that 7.8 out of 1000 (0.78%) volunteers would die during the same period. Moreover, as this review goes on to say: “These findings were not confirmed by experimental studies.”
The most highly cited paper in the kindness literature (with 597 citations at the time of the last search) purports 4
to provide evidence that kind acts boosts the well-being of the actor (Sonja Lyubomirsky, Sheldon, & Schkade, 2005). However, the article does not report the size of the sample, the dependent measure, or any inferential statistics (for example, effect size or significance). Email correspondence with the author revealed that the data are no longer available.
These averages are approximate (~), because the age and sex ratio of the samples were not available for some 5
studies.
Although see Coyne (2014a, 2014b) for critical commentary on (Sin & Lyubomirsky, 2009) and (Bolier et al., 6
2013).
Quotes Falsely Attributed to Winston Churchill: http://www.winstonchurchill.org/resources/quotations/135-7
quotes-falsely-attributed.
"44
Tabl
e 1
Mai
n ch
arac
teri
stic
s of
stu
dies
incl
uded
in th
e m
eta-
anal
ysis
Stud
yT
heor
ySe
xA
geL
ocat
ion
Don
orIn
terv
entio
n (I
V)
Con
trol
Rec
ipie
nt(s
)O
utco
me
(DV
)n1
(I)
n2 (C
)d
Not
es
Akn
in, B
arrin
gton
-Lei
gh, e
t al.
(201
3)St
udy
3Pr
osoc
ial
3821
Can
ada
/ Sou
th A
fric
aTy
pica
lPr
osoc
ial P
urch
ase
Pers
onal
Pu
rcha
seA
nony
mou
s Si
ck C
hild
ren
PA10
010
00.
46D
onat
ed k
ids g
oody
bag
. No
effe
ct o
n LS
.
Akn
in, B
roes
ch, e
t al.
(201
5)St
udy
1Pr
osoc
ial
4245
Vanu
atu
Typi
cal
Pros
ocia
l Pur
chas
ePe
rson
al
Purc
hase
Fam
ily /
Frie
nds
PA13
130.
93
Akn
in, B
roes
ch, e
t al.
(201
5)St
udy
2Pr
osoc
ial
70~3
Vanu
atu
Typi
cal
Don
ate
own
swee
tsD
onat
e ot
her
swee
tsPu
ppet
Smili
ng20
200.
30
Akn
in, D
unn,
et a
l. (2
013)
Stud
y 3
Pros
ocia
l34
21.0
0C
anad
aTy
pica
lSo
cial
/Hig
h Im
pact
Pers
onal
/Low
Im
pact
Frie
ndSH
S12
360.
70
Akn
in, F
leer
acke
rs, e
t al.
(201
4)Pr
osoc
ial
4119
.90
USA
Typi
cal
Pros
ocia
l Pur
chas
ePe
rson
al
Purc
hase
Ano
nym
ous
Sick
Chi
ldre
nPA
6059
0.38
Don
ated
kid
s goo
dy b
ag. O
ther
resu
lts n
s. Th
ird
party
rate
d pr
osoc
ial g
roup
with
gre
ater
hap
pine
ss
d=0.
44.
Akn
in, H
amlin
, et a
l. (2
012)
Pros
ocia
l55
1.90
Can
ada
Typi
cal
Don
ate
own
swee
tsD
onat
e ot
her
swee
tsPu
ppet
Smili
ng20
200.
46
Ald
en, &
Tre
w (2
013)
Posi
tive A
ffect
/ So
cial
Anx
iety
2819
.56
Can
ada
Soci
ally
A
nxio
usA
KB
EA
nyon
ePA
3843
0.50
Als
o in
clud
ed ‘L
ife D
etai
ls’ c
ontro
l con
ditio
n.
Buc
hana
n, &
Bar
di (2
010)
No
theo
ry26
38.0
0U
K?
Typi
cal
AK
Nov
elty
Any
one
LS28
280.
21
Dun
n, A
knin
, et a
l. (2
008)
Stud
y 3
Pros
ocia
l26
naC
anad
aTy
pica
lPr
osoc
ial P
urch
ase
Pers
onal
Pu
rcha
seA
nyon
e /
Cha
rity
H23
230.
67
Gee
nen,
Hoh
eluc
hter
, et a
l. (2
014)
Pros
ocia
l / E
gois
m21
naG
erm
any
Typi
cal
Pros
ocia
l Pur
chas
ePe
rson
al
Purc
hase
Frie
nds
H34
340.
70
Layo
us, L
ee, e
t al.
(201
3)Pr
osoc
ial /
Eas
t v
Wes
t38
naU
SA/K
orea
Typi
cal
AK
Con
trol
Any
one
WB
213
104
0.18
Layo
us, N
elso
n, e
t al.
(201
2)Pr
osoc
ial /
Pee
r A
ccep
tanc
ena
10.6
0C
anad
aTy
pica
lA
KW
here
abou
tsA
nyon
eH
138
138
0.16
Mar
tela
, & R
yan
(201
6)Pr
osoc
ial /
A
nony
mou
s / S
DT
3620
.40
naTy
pica
lB
enev
olen
ceN
eutra
lC
harit
yPA
3442
0.55
No
cost
; fre
eric
e.co
m
Mon
grai
n, C
hin,
et a
l. (2
011)
East
ern
tradi
tions
/ SI
T16
33.6
3C
anad
aTy
pica
l /
Anx
ious
AK
Mem
ory
Any
one
SHI
229
229
0.31
Effe
ct w
as n
ot g
reat
er fo
r ‘an
xiou
s’ pa
rtici
pant
s
Nel
son,
Del
la P
orta
, et a
l. (2
015)
US
Pros
ocia
l39
19.1
1U
STy
pica
lA
KW
ork
Any
one
WB
5252
-0.1
0C
onfo
unde
d by
‘aut
onom
y’ m
anip
ulat
ion.
Nel
son,
Del
la P
orta
, et a
l. (2
015)
Kor
eaPr
osoc
ial
5420
.77
Kor
eaTy
pica
lA
KW
ork
Any
one
WB
5757
0.82
ns. C
onfo
unde
d by
‘aut
onom
y’ m
anip
ulat
ion.
Nel
son,
Lay
ous,
et a
l. (2
016)
Pros
ocia
l40
29.9
5U
SATy
pica
lA
KSe
lfO
ther
/Wor
ldPF
238
118
0.29
Als
o in
clud
ed N
eutra
l con
trol.
O'C
onne
ll, O
'She
a, e
t al.
(201
6)PP
A/S
ocia
l Sup
port
~54
~34.
17U
SATy
pica
lA
KSe
lfSo
cial
N
etw
ork
SHS
2831
0.33
Als
o in
clud
ed N
eutra
l con
trol.
Sign
ifica
nt e
ffect
s on
oth
er o
utco
me
(RS)
.
Ouw
enee
l, Le
Bla
nc, e
t al.
(201
4)St
udy
2Po
sitiv
e Ps
ycho
logy
/ A
cade
mic
1620
.88
Net
herla
nds
Typi
cal
AK
Neu
tral
Act
ivity
Any
one
SR-P
(N)E
2524
0.97
“The
kin
dnes
s int
erve
ntio
n ha
d a
posi
tive
influ
ence
…th
ough
not
in th
e lo
ng ru
n.”
Trew
, & A
lden
(201
5)So
cial
Avo
idan
ce26
20.4
7C
anad
aA
nxio
usA
KSo
cial
Ex
posu
reA
nyon
ePA
3841
0.00
Als
o in
clud
ed ‘L
ife D
etai
ls’,
cont
rol c
ondi
tion.
Pa
rtici
pant
s in
treat
men
t con
ditio
n “w
ere
info
rmed
th
at a
cts o
f kin
dnes
s may
redu
ce a
nxie
ty b
y af
fect
ing
moo
d an
d so
cial
inte
ract
ions
”.
Whi
llans
, Dun
n, e
t al.
(201
6)St
udy
2Pr
osoc
ial
5072
.02
USA
Hyp
erte
nse
Pros
ocia
l Pur
chas
ePe
rson
al
Purc
hase
Any
one
WB
3637
0.19
No
cost
. Effe
ct o
n bl
ood
pres
sure
d=0
.63,
0.9
7
Not
e. N
= sa
mpl
e si
ze; S
ex =
% m
en in
sam
ple;
AK
=Act
s of K
indn
ess;
BE=
Beh
avio
ural
Exp
erim
ents
; DSA
=Dep
ress
ive
Sym
ptom
s; H
=Hap
pine
ss; L
S=Li
fe S
atis
fact
ion;
na
= no
t ava
ilabl
e; P
A=P
ositi
ve A
ffect
; PF=
Psyc
holo
gica
l Flo
uris
hing
; RS=
Rel
atio
nshi
p Sa
tisfa
ctio
n; S
=Stu
dy; S
A=S
ocia
l A
nxie
ty; S
HI=
Stee
n H
appi
ness
Inde
x; S
HS=
Subj
ectiv
e H
appi
ness
Sca
le ;
SIT=
Soci
al In
terd
epen
denc
e Th
eory
; SR
-P(N
)E=S
elf-
repo
rt Po
sitiv
e an
d (N
egat
ive)
Em
otio
ns; U
G=U
nder
grad
uate
; WB
=Wel
l-bei
ng.
Figure 1: Flow diagram of the search and selection procedure of studies
Full-text articles excluded (n = 29)
1) No kind acts, just recall n=3
2) Counting kind acts, no new ones n=4
3) Expected or imaginary kindness n=3
4) No control n=25) Comparing kindness on
other IV n=46) Kind acts embedded
with other positive activities n=6
7) Incomplete description of experiment n=1
8) Review or meta-analysis n=3
9) Correlational n=3
Records after duplicates removed (n = 428)
Studies included in quantitative synthesis
(meta-analysis)(n = 21)
Full-text articles assessed for eligibility
(n = 48)
Records excluded (n = 380)
Records screened (n = 376)
Additional records identified through other sources
(n = 19)
Identification
Eligibility
Included
Screening
Records identified through database searching
(n = 639)
Figure 2: Forest plot for the effect of kindness acts on actor’s well-being
OVERALL
-0.5 0 0.5 1 1.5 2
Effect Size (d)
Whillans Dunn et al. (2016; S2)Trew & Alden (2015)Ouweneel Le Blanc et al. (2014; S2)O'Connell O'Shea et al. (2016)Nelson Layous et al. (2016)Nelson Della Porta et al. (2015; USA)Nelson Della Porta et al. (2015; Korea)Mongrain Chin et al. (2011)Martela & Ryan (2016)Layous Nelson et al. (2012)Layous Lee et al. (2013)Geenen Hoheluchter et al. (2014)Dunn Aknin et al. (2008; S3)Buchanan & Bardi (2010)Alden & Trew (2013)Aknin Hamlin et al. (2012)Aknin Fleerackers et al. (2014)Aknin Dunn et al. (2013; S3)Aknin Broesch et al. (2015; S2)Aknin Broesch et al. (2015; S1)Aknin Barrington-Leigh et al. (2013; S3)
0.19 [-0.26, 0.64] 0.00 [-0.45, 0.45] 0.97 [ 0.38, 1.56] 0.33 [-0.18, 0.84] 0.29 [ 0.07, 0.51] 0.82 [ 0.43, 1.21]-0.10 [-0.49, 0.29] 0.31 [ 0.13, 0.49] 0.55 [ 0.10, 1.00] 0.16 [-0.08, 0.40] 0.18 [-0.06, 0.42] 0.70 [ 0.21, 1.19] 0.67 [ 0.08, 1.26] 0.21 [-0.32, 0.74] 0.50 [ 0.05, 0.95] 0.46 [-0.17, 1.09] 0.38 [ 0.03, 0.73] 0.70 [ 0.03, 1.37] 0.30 [-0.33, 0.93] 0.93 [ 0.13, 1.73] 0.46 [ 0.19, 0.73]
0.36 [ 0.26, 0.47]
Figure 3: Funnel plot for the effect of acts of kindness on actor’s well-being
Effect Size (d)
Sta
ndar
d E
rror
0.41
0.307
0.205
0.102
0
-0.5 0 0.5 1
Supplementary Material for ‘Happy to Help”?
S1: Organisations working on kindness and happiness
Ark Project Now (ARK) started with a simple question: “What if kindness became normal?” http://www.arkprojectnow.com Be Kind to Human Kind aims to celebrate people and their kind acts and is a platform to share positive news, stories, photos, videos, poems and quotes. http://bk2hk.org/about/ Happify defines itself as “the single [online] destination for effective, evidence-based solutions for emotional health and well-being in the 21st century.” http://www.happify.com Life Vest Inside is a “non-profit organization dedicated to empowering the masses to engage in acts of love and kindness.” http://www.lifevestinside.com Random Acts is “committed to creating a network of kindness through strategic partnerships with organizations from around the world.” http://www.randomacts.org Random Acts of Kindness (RAK) is a foundation that encourages the spread of kindness in schools, communities and homes. https://www.randomactsofkindness.org SpreadKindness is a “non-profit organization dedicated to encouraging and empowering people to practice kindness in their everyday lives. We provide individuals and groups with tools, ideas, projects and events that help make the world a kinder place.” http://www.spreadkindness.org The Sugar Cube Factory is a website that helps people to distribute (digitally) their words of kindness around the world. http://www.sugarcubefactory.com The Cambridge Prosociality and Well-being Lab at the University of Cambridge investigates “the psychology and biology of human kindness and well-being.” http://cpwlab.azurewebsites.net/Welcome.aspx The Center for Compassion and Altruism Research and Education, Stanford School of Medicine (CCARE) investigates methods for cultivating compassion and promoting altruism within individuals and society http://ccare.stanford.edu The Greater Good Science Center (GGSC) at the University of California, Berkeley “studies the psychology, sociology, and neuroscience of well-being, and teaches skills that foster a thriving, resilient and compassionate society.”
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http://greatergood.berkeley.edu/about The Institute for Research on Unlimited Love seeks to “increase public awareness of…(1) new scientific investigations…; (2) insights of the world’s great philosophical, spiritual and theological traditions; and (3) inspiring works of love by exemplars across the world.” http://unlimitedloveinstitute.org/about.php
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S2: List of 48 reviewed articles (* = included in meta-analysis)
Aknin, L., Dunn, E., Sandstrom, G., & Norton, M. (2013). Does social connection turn good deeds into good feelings?
*Aknin, L. B., Barrington-Leigh, C. P., Dunn, E. W., Helliwell, J. F., Burns, J., Biswas-Diener, R., . . . Norton, M. I. (2013). Prosocial spending and well-being: Cross-cultural evidence for a psychological universal. Journal of Personality and Social Psychology, 104(4), 635-652. doi:10.1037/a0031578 10.1037/a0031578.supp (Supplemental)
*Aknin, L. B., Broesch, T., Hamlin, J. K., & Van de Vondervoort, J. W. (2015). Prosocial behavior leads to happiness in a small-scale rural society. Journal of Experimental Psychology: General, 144(4), 788-795. doi:10.1037/xge0000082
*Aknin, L. B., Dunn, E. W., & Norton, M. I. (2012). Happiness runs in a circular motion: Evidence for a positive feedback loop between prosocial spending and happiness. Journal of Happiness Studies, 13(2), 347-355. doi:10.1007/s10902-011-9267-5
Aknin, L. B., Dunn, E. W., Whillans, A. V., Grant, A. M., & Norton, M. I. (2013). Making a difference matters: Impact unlocks the emotional benefits of prosocial spending. Journal of Economic Behavior & Organization, 88, 90-95. doi:10.1016/j.jebo.2013.01.008
*Aknin, L. B., Fleerackers, A. L., & Hamlin, J. K. (2014). Can third-party observers detect the emotional rewards of generous spending? Journal of Positive Psychology, 9(3), 198-203. doi:10.1080/17439760.2014.888578
*Aknin, L. B., Hamlin, J. K., & Dunn, E. W. (2012). Giving leads to happiness in young children. PLoS ONE, 7(6). doi:10.1371/journal.pone.0039211
Aknin, L. B., Sandstrom, G. M., Dunn, E. W., & Norton, M. I. (2011). It’s the recipient that counts: Spending money on strong social ties leads to greater happiness than spending on weak social ties. PLoS ONE, 6(2). doi:10.1371/journal.pone.0017018
Aknin, L. B., Van Boven, L., & Johnson-Graham, L. (2015). Abstract construals make the emotional rewards of prosocial behavior more salient. The Journal of Positive Psychology, 10(5), 458-462. doi:10.1080/17439760.2014.967801
*Alden, L. E., & Trew, J. L. (2013). If it makes you happy: Engaging in kind acts increases positive affect in socially anxious individuals. Emotion, 13(1), 64-75. doi:10.1037/a0027761
*Buchanan, K. E., & Bardi, A. (2010). Acts of Kindness and Acts of Novelty Affect Life Satisfaction. Journal of Social Psychology, 150(3), 235-237.
Chancellor, J., Layous, K., & Lyubomirsky, S. (2015). Recalling positive events at work makes employees feel happier, move more, but interact less: A 6-week randomized controlled intervention at a Japanese workplace. Journal of Happiness Studies, 16(4), 871-887. doi:10.1007/s10902-014-9538-z
Drozd, F., Mork, L., Nielsen, B., Raeder, S., & Bjorkli, C. A. (2014). Better Days - A randomized controlled trial of an internet-based positive psychology intervention. Journal of Positive Psychology, 9(5), 377-388. doi:10.1080/17439760.2014.910822
*Dunn, E. W., Aknin, L. B., & Norton, M. I. (2008). Spending money on others promotes happiness. Science, 319(5870), 1687-1688. doi:10.1126/science.1150952
Gander, F., Proyer, R. T., Ruch, W., & Wyss, T. (2013). Strength-based positive interventions: Further evidence for their potential in enhancing well-being and alleviating depression. Journal of Happiness Studies, 14(4), 1241-1259. doi:10.1007/s10902-012-9380-0
*Geenen, N. Y. R., Hohelüchter, M., Langholf, V., & Walther, E. (2014). The beneficial effects of prosocial spending on happiness: Work hard, make money, and spend it on others? The Journal of Positive Psychology, 9(3), 204-208. doi:10.1080/17439760.2014.891154
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Haworth, C. M. A., Nelson, S. K., Layous, K., Carter, K., Bao, K. J., Lyubomirsky, S., & Plomin, R. (2016). Stability and Change in Genetic and Environmental Influences on Well-Being in Response to an Intervention. PLoS ONE, 11(5). doi:10.1371/journal.pone.0155538
Huang, Y. H. (2016). Downward Social Comparison Increases Life-Satisfaction in the Giving and Volunteering Context. Social Indicators Research, 125(2), 665-676. doi:10.1007/s11205-014-0849-6
Kerr, S. L., O'Donovan, A., & Pepping, C. A. (2015). Can Gratitude and Kindness Interventions Enhance Well-Being in a Clinical Sample? Journal of Happiness Studies, 16(1), 17-36. doi:10.1007/s10902-013-9492-1
*Layous, K., Lee, H., Choi, I., & Lyubomirsky, S. (2013). Culture matters when designing a successful happiness-increasing activity: A comparison of the United States and South Korea. Journal of Cross-Cultural Psychology, 44(8), 1294-1303. doi:10.1177/0022022113487591
Layous, K., Nelson, Kurtz, & Lyubomirsky. (2016). What triggers prosocial effort? A positive feedback loop between positive activities, kindness, and well-being.
*Layous, K., Nelson, S. K., Oberle, E., Schonert-Reichl, K. A., & Lyubomirsky, S. (2012). Kindness Counts: Prompting Prosocial Behavior in Preadolescents Boosts Peer Acceptance and Well-Being. PLoS ONE, 7(12). doi:10.1371/journal.pone.0051380
Liu, W., & Aaker, J. (2008). The happiness of giving: The time-ask effect. Journal of Consumer Research, 35(3), 543-557. doi:10.1086/588699
Lyubomirsky, S., & Layous, K. (2013). How do simple positive activities increase well-being? Current Directions in Psychological Science, 22(1), 57-62. doi:10.1177/0963721412469809
Lyubomirsky, S., Sheldon, K. M., & Schkade, D. (2005). Pursuing happiness: The architecture of sustainable change. Review of General Psychology, 9(2), 111-131. doi:10.1037/1089-2680.9.2.111
*Martela, F., & Ryan, R. M. (2016). Prosocial behavior increases well-being and vitality even without contact with the beneficiary: Causal and behavioral evidence. Motivation and Emotion, 40(3), 351-357. doi:10.1007/s11031-016-9552-z
McNulty, J. K., & Fincham, F. D. (2012). Beyond positive psychology? Toward a contextual view of psychological processes and well-being. American Psychologist, 67(2), 101-110. doi:10.1037/a0024572
Meier, S., & Stutzer, A. (2008). Is Volunteering Rewarding in Itself? Economica, 75(297), 39-59. doi:10.1111/j.1468-0335.2007.00597.x
*Mongrain, M., Chin, J. M., & Shapira, L. B. (2011). Practicing Compassion Increases Happiness and Self-Esteem. Journal of Happiness Studies, 12(6), 963-981. doi:10.1007/s10902-010-9239-1
*Nelson, S. K., Della Porta, M. D., Bao, K. J., Lee, H. C., Choi, I., & Lyubomirsky, S. (2015). ‘It’s up to you’: Experimentally manipulated autonomy support for prosocial behavior improves well-being in two cultures over six weeks. The Journal of Positive Psychology, 10(5), 463-476. doi:10.1080/17439760.2014.983959
Nelson, S. K., Layous, K., Cole, S. W., & Lyubomirsky, S. (2016). Do Unto Others or Treat Yourself? The Effects of Prosocial and Self-Focused Behavior on Psychological Flourishing. Emotion. doi:10.1037/emo0000178 10.1037/emo0000178.supp (Supplemental)
Ng, W. (2016). Use of positive interventions: Does neuroticism moderate the sustainability of their effects on happiness? The Journal of Positive Psychology, 11(1), 51-61. doi:10.1080/17439760.2015.1025419
*O’Connell, B. H., O’Shea, D., & Gallagher, S. (2016). Enhancing social relationships through positive psychology activities: A randomised controlled trial. The Journal of Positive Psychology, 11(2), 149-162. doi:10.1080/17439760.2015.1037860
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Otake, K., Shimai, S., Tanaka-Matsumi, J., Otsui, K., & Fredrickson, B. L. (2006). Happy people become happier through kindness: A counting kindnesses intervention. Journal of Happiness Studies, 7(3), 361-375. doi:10.1007/s10902-005-3650-z
*Ouweneel, E., Le Blanc, P. M., & Schaufeli, W. B. (2014). On being grateful and kind: Results of two randomized controlled trials on study-related emotions and academic engagement. The Journal of Psychology: Interdisciplinary and Applied, 148(1), 37-60. doi:10.1080/00223980.2012.742854
Poulin, M. J., Brown, S. L., Dillard, A. J., & Smith, D. M. (2013). Giving to Others and the Association Between Stress and Mortality. American Journal of Public Health, 103(9), 1649-1655. doi:10.2105/Ajph.2012.300876
Pressman, S. D., Kraft, T. L., & Cross, M. P. (2015). It’s good to do good and receive good: The impact of a ‘pay it forward’ style kindness intervention on giver and receiver well-being. The Journal of Positive Psychology, 10(4), 293-302. doi:10.1080/17439760.2014.965269
Proctor, C., Maltby, J., & Linley, P. A. (2011). Strengths use as a predictor of well-being and health-related quality of life. Journal of Happiness Studies, 12(1), 153-169. doi:10.1007/s10902-009-9181-2
Raposa, E. B., Laws, H. B., & Ansell, E. B. (2016). Prosocial Behavior Mitigates the Negative Effects of Stress in Everyday Life. Clinical psychological science : a journal of the Association for Psychological Science, 4(4), 691-698. doi:10.1177/2167702615611073
Reyniers, D., & Bhalla, R. (2013). Reluctant altruism and peer pressure in charitable giving. Judgment and Decision Making, 8(1), 7-15.
Rudd, M., Aaker, J., & Norton, M. I. (2014). Getting the most out of giving: Concretely framing a prosocial goal maximizes happiness. Journal of Experimental Social Psychology, 54, 11-24. doi:10.1016/j.jesp.2014.04.002
Schwartz, C. E., & Sendor, R. M. (1999). Helping others helps oneself: response shift effects in peer support. Social Science & Medicine, 48(11), 1563-1575. doi:10.1016/s0277-9536(99)00049-0
Sin, N. L., & Lyubomirsky, S. (2009). Enhancing well-being and alleviating depressive symptoms with positive psychology interventions: a practice-friendly meta-analysis. Journal of Clinical Psychology, 65(5), 467-487. doi:10.1002/jclp.20593
*Trew, J. L., & Alden, L. E. (2015). Kindness reduces avoidance goals in socially anxious individuals. Motivation and Emotion, 39(6), 892-907. doi:10.1007/s11031-015-9499-5
Weinstein, N., DeHaan, C. R., & Ryan, R. M. (2010). Attributing autonomous versus introjected motivation to helpers and the recipient experience: Effects on gratitude, attitudes, and well-being. Motivation and Emotion, 34(4), 418-431. doi:10.1007/s11031-010-9183-8
Weinstein, N., & Ryan, R. M. (2010). When helping helps: Autonomous motivation for prosocial behavior and its influence on well-being for the helper and recipient. Journal of Personality and Social Psychology, 98(2), 222-244. doi:10.1037/a0016984
Weiss, L. A., Westerhof, G. J., & Bohlmeijer, E. T. (2016). Can We Increase Psychological Well-Being? The Effects of Interventions on Psychological Well-Being: A Meta-Analysis of Randomized Controlled Trials. PLoS ONE, 11(6), e0158092. doi:10.1371/journal.pone.0158092
*Whillans, A. V., Dunn, E. W., Sandstrom, G. M., Dickerson, S. S., & Madden, K. M. (2016). Is spending money on others good for your heart? Health Psychology, 35(6), 574-583. doi:10.1037/hea0000332
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Table S1
Reasons for excluding studies from final 48
Reason for Exculsion Studies Excluded
Use of kindness recall rather than acts of kindness
Aknin, Barrington-Leigh et al., Study 2a/b; Aknin, Dunn, & Norton, 2012; Aknin et al, 2013, Study 2; Aknin et al., 2011
Counting acts of kindness, but no new ones instigated
Gander et al., 2013; Kerr et al., 2015; Ng, 2016; Otake, 2006
Use of expected or imaginary kindness Aknin et al., 2015; Huang, 2016; Weinstein et al., 2010
No control group Pressman et al., 2015; Rudd et al., 2014
Comparing two kindness groups on a different I.V.
Social connection: Aknin et al 2013. Impact: Aknin et al, 2013, Study 1. Intentions: Liu & Aaker, 2008; Peer pressure: Reyniers & Bhalla, 2013. Autonomy: Weinstein & Ryan, 2010
Including acts of kindness with other positive activity interventions, i.e. no direct test of kindness
Chancellor, et al., 2015; Drozd et al., 2014; Haworth, et al., 2016; Layous et al., 2016; Meier & Stutzer, 2008; Schwartz & Sendor, 1999
Incomplete description of experimental details
Lyubomirsky et al., 2005
Review or meta-analysisLyubomirsky & Layous, 2013; McNulty, 2012; Sin & Lyubomirsky, 2009
Correlational studiesAknin, Barrington-Leigh, et al., Study 1; Dunn, et al., 2008, Study 1 & 2; Huang, 2016; Poulin et al, 2013; Proctor, 2011; Raposa, 2016