Date post: | 15-Jan-2016 |
Category: |
Documents |
Upload: | eleanor-lambert |
View: | 221 times |
Download: | 0 times |
Language Language productionproduction
Holly BraniganHolly Branigan
Email: Email: [email protected]@ed.ac.ukOffice: US46 Office: US46
Office hour: Mon 10-11Office hour: Mon 10-11Psychling coffee hour: Wed 11-12Psychling coffee hour: Wed 11-12
Course overviewCourse overview
Overview of the production systemMethodological issuesLexical accessSyntactic encodingBeyond the sentence…
OverviewOverview What does production involve? Methodological challenges:
– Studying comprehension vs production Approaches:
– Observational approaches Advantages/disadvantages
– Experimental approaches Challenges: controlling input and output Two classes of methods:
– Manipulating pathways (altering processor’s state)– Manipulating message
– Neurophysiological approaches
BackgroundBackground
Production forms half of language ability:– Input to comprehension– More difficult problem than comprehension?
e.g. Evidence from 1st & 2nd language acqn
The problem:– Expressing non-ordered conceptual message
via ordered array of sounds.– But: under several constraints, in real time.
What we What we don’tdon’t do doH: How much money is there in my current account and in my deposit account?
<SILENCE>
H: Hello?<SILENCE>
C: Colourless green ideas sleep furiously.
H: How much money is there in my current account and in my deposit account?
<SILENCE>
C: Your current a-ccount encompasses two hundred pounds. I cannot access how..<SILENCE>.. in your deposit account
money much is there.
Undesirable featuresUndesirable features
Meaningless and irrelevant content. Long silences, strange pausing. Infelicities of vocabulary and structure:
– ‘Your current account encompasses £200’– ‘I cannot access how in your deposit
account money much is there.’ Strange intonation and pronunciation:
– ‘Your current a-ccount’– ‘Sleeeeeep’
What we What we do do dodo
Speakers must produce utterances with:– Appropriate meaningful content;– Appropriate lexical items;– Appropriate syntax - grammatical and
appropriate word order and structure;– Appropriate pronunciation, intonation, and
phrasing. And they must do this fluently, in real
time.
Getting the form rightGetting the form right
Speakers have to get every aspect of the form right, whether or not germane to message.– cf. Hearers - details of form can
sometimes (often?) be ignored (e.g. missing words, not paying attention).
Getting the content wrongGetting the content wrong Paradox: adept at getting form right but content
wrong:– Subject-verb agreement errors
e.g. The report about the fires are very long Less than 5% errors in expmt designed to elicit them (Bock &
Miller 1991).
– Serious structural anomalies (unparseable) 0.5% utterances (Deese 1984).
– Sound/word errors (Garnham et al 1982): Sound errors 3.2/10,000 words Word errors 5.1/10,000 words
– Can you put the desk back on my book when you’ve finished with it?
– It’ll get fast a lot hotter if you put the burner on.
Doing it in timeDoing it in time Strongest constraint may be fluency:
– have to get form right under time pressure.
Incrementality:– ‘Work with what you’ve got’– Flexibility: allows speaker to say something
quickly, also respond to changing environment.
Modularity:– ‘Work only with what you’ve got’– Regulate flow of information.
An outline of An outline of sentence productionsentence production
Three broad stages: – Conceptualisation
deciding on the message (= meaning to express)
– Formulation turning the message into linguistic representations Grammatical encoding (finding words and putting them
together) Phonological encoding (finding sounds and putting them
together)
– Articulation speaking (or writing or signing)
Methodology: BackgroundMethodology: Background
‘..an intrinsically more difficult subject to study than language comprehension’ – Not susceptible to experimental study?
Solutions:– Evidence from other disciplines
e.g., social psychology, linguistics, AI…
– Cognitive psychology: Historically: observational methods Recently: experimental methods
What’s the problem?What’s the problem? Comprehension:
– Can control input precisely– Moving from language to conceptual representation
e.g., understanding anaphora: participants read same texts; measure reading times
Production:– How do we control input?– Moving from (unobservable) conceptual representation to
language e.g., when participants produce anaphora, do they do so on the
same basis?
BUT: end product is observable in production but not comprehension
MeasuresMeasures What people say:
– Under which circumstances do they produce particular words, utterances etc
– May be intended, or may be errors– How frequently do they do this
Timecourse:– How quickly do people produce language
Neurophysiological:– How is language production represented in the
brain?
Observational methods: Observational methods: Analyses of spontaneous speechAnalyses of spontaneous speech
– Researchers’ own corpora (e.g., Stemberger, 1985)
– Publicly available corpora: Non-experimental
(London –Lund - Svartvik & Quirk, 1980; Wall Street Journal; CHILDES – MacWhinney & Snow, 1990)
Experimental (controlled features)(Map Task Corpus – Thompson et al., 1993).
– Controlled experimental tasks: Berman & Slobin, 1994.
Observation: Observation: Distributional analysesDistributional analyses
Fluent speech:– Sentence types, verb forms, prosodic markers etc (Deese,
1984)
– Distribution of extraposed structures (Arnold, Wasow, Losongco & Ginstrom, 2000)
– Distribution of thuh vs thee (Clark & Fox-Tree, 1997)
– Distribution of reduced phonological forms (Bard et al., 2000)
Disfluent speech:– Scope of utterance planning (Ford & Holmes, 1978; Beattie, 1983)
– Error detection and correction (Levelt, 1983)
Observational analyses of Observational analyses of disfluenciesdisfluencies
Speech errors– Pattern of errors (Stemberger, 1985)
– Relative frequency of errors
Problems:– Paucity of data
errors = 3% self-interruptions (Blackmer & Mitton, 1991)
– Bias/inaccuracies in corpus transcription: Transcriber bias/inaccuracy (Ferber, 1991) Distributional characteristics of language
– Categorisation problems
Experimental approachesExperimental approaches
Not prey to same problems as observational studies:– Reduces observer bias; – isolates phenomenon of interest; – increases potential for systematic observation.
Different problems!– How to control input and output?– Input: ecological validity problem (‘controlling
thoughts’)– Output: controlling responses:
response specification - artificiality ‘exuberant responding’ – loss of data
Controlling inputControlling input Philosophical problems
– Does language production require ‘freedom of thought’?
Practical issues:– Problem:
how to characterise non-linguistic message?– Solution:
hold message constant, and manipulate ‘pathway’ of processing instead (state of processor)
– Priming paradigms (effects of prior processing)– Creating conflicts (cf. ambiguity resolution in
comprehension)
Controlling output: Controlling output: Specified elicitationSpecified elicitation
Specified elicitation: tell participants what to say.– Usually used when semantic/syntactic
structure not of interest.– Responses specified in advance for given
stimulus: Picture naming Implicit priming (Roelofs & Meyer, 1998)
– DOG – BONE– SAIL – BOAT
Array description (Smith & Wheeldon, 2001) Repeating sentences (Ferreira, 1993)
Controlling output: Controlling output: Normative elicitationNormative elicitation
Normative elicitation: use stimuli designed to induce desired response.– Pictures of events/objects
– Descriptions of objects‘A very large mammal that swims in the sea and
was widely hunted’
– Questions/fragments ‘The junior surgeon handed the senior
surgeon….’
Manipulating pathways: Manipulating pathways: Error elicitationError elicitation
Basic idea: – set up situations which lead to errors in ‘natural’ speech
Agreement errors:– Participants repeat and complete sentence fragments:
The key to the cabinets…were heavy
– Cause of errors: Conflict between number (or gender) of head and local
noun
– Used to examine e.g. contribution of conceptual info and morphology to agreement
(Bock & Eberhard, 1993; Vigliocco, Butterworth & Semenza, 1995)
Manipulating pathways: Manipulating pathways: primingpriming
Priming: – change probability/ease of producing particular
utterance.– Cooperating (rather than competing) plan.
Concurrent presentation:– Distractor and target presented at same time
Consecutive presentation:– Distractor presented and processed before
target
Manipulating pathways:Manipulating pathways:Concurrent presentationConcurrent presentation
Picture-word interference:– Target stimulus:
– presented visually– must be named
– Distractor stimulus:– presented auditorily or visually– must be ignored
– Stimulus onsets may be simultaneous or staggered
Manipulating pathways:Manipulating pathways:Concurrent presentationConcurrent presentation
Used for exploring timecourse of lexical access (Schriefers, Meyer & Levelt, 1990)
– Targets were objects such as sheep– Distractors:
Different relations to target:– Phonologically-related (sheet)– Semantically-related (goat)– Unrelated (bed)
Different presentation onsets:– 150 ms before target– Simultaneous with target– 150 ms after target
Manipulating pathways:Manipulating pathways:Concurrent presentationConcurrent presentation
Results: – early in timecourse:
semantic distractors slow naming more than unrelated or phonological distractors;
– later in timecourse: phonological distractors speed naming more than
unrelated or semantic distractors.
Control experiment used non-production (recognition) task– Excluded comprehension-based explanation?
Manipulating pathways:Manipulating pathways:Consecutive presentationConsecutive presentation
‘Prime’ stimulus processed – Cf concurrent presentation, where
distractor stimulus is ignored
Target then processed– How does prior processing of prime
affect processing of target?
Manipulating pathways:Manipulating pathways:Consecutive presentationConsecutive presentation
Word-priming (Wheeldon & Monsell, 1994)
– Participants read dictionary definitions and generate response
‘A very large mammal that swims in the sea and was widely hunted’
– Then picture of related object (shark) presented
– Here, slower responses when prime is related than unrelated
– Attributed to competitive activation
Manipulating messageManipulating message Oldest method of studying production?
– Create minimal contrasts in intended message;– study differences in realisation of message.
‘Simply describe’ (Osgood, 1971)
– Enact (or show film) of minimally distinct eventse.g., ball rolling across table vs man holding ball before ball rolls across table– Use of indefinite article a in first case vs definite article the in
second case
Very simple method – but many problems:– How do we characterise ‘minimal semantic contrast’?
Neurophysiological Neurophysiological MeasuresMeasures
Recent technological developments allow research on neurophysiological aspects of production.– Which areas of the brain are involved?– What is the timecourse of processing?– Are different
areas/processes/timecourses associated with different aspects of production?
Some MethodsSome Methods Event-related potentials (ERPS):
– brain responses time-locked to some "event“– sensory stimulus (visual flash or auditory sound), mental
event (recognition of a specified target stimulus), or omission of stimulus (increased time gap between stimuli).
functional magnetic resonance imaging (fMRI):– form of magnetic resonance imaging of brain registering
blood flow to functioning areas of the brain
Positron emission tomography (PET):– uses detection of subatomic particles to identify how
different areas of brain function.
NB: other methods coming into use
SummarySummary Language production requires assembling multiple levels
of linguistic structure accurately and fluently, in real time.
Language production in some ways harder to study than comprehension:– How to control input?
Many methods:– keep propositional content constant– create and study variations in processing mechanisms, rather
than effects of variations in message itself.– Problem remains: what is relationship between conceptual and
linguistic processing? New technologies offer new possibilities for tracing
timecourse and neurophysiological underpinnings of language production
Assessing models of Assessing models of production production
Semantic interference effect– Objects are harder to name in presence of
semantically-related word.– Effect may be related to conceptual processing or
feedback from phonological processing. fMRI study:
– present same stimuli, and see which areas of brain activated.
– results: differential activation of various areas in semantic-interference condition relative to control condition; consistent with phonological feedback. (de Zubicaray,Wilson, McMahon & Muthiah, 2001)
Identifying neural bases Identifying neural bases of productionof production
Grammatical gender: – central aspect of lexical representation in
many languages. fMRI study: which areas of brain
activated in gender production?– compared producing gender-marked
determiner with naming object itself.– results: pronounced activation of single
region in Broca’s area when producing determiner.
(Heim, Opitz & Friederici, 2002).