Motor cognition, cognition, Motor communication and and - - PowerPoint PPT Presentation
Motor cognition, cognition, Motor communication and and communication the language faculty the language faculty Summer Institute, , The Origins The Origins of of Language Language Summer Institute UQAM, June June 23, 2010 23, 2010
Pierre Jacob Pierre Jacob Institut Jean Institut Jean Nicod Nicod Paris, France Paris, France http://www.institutnicod http://www.institutnicod
Summer Institute Summer Institute, , The Origins The Origins of
Language UQAM, UQAM, June June 23, 2010 23, 2010
(1) Contribution of (1) Contribution of somatotopic motor representations somatotopic motor representations of actions
triggered triggered by perception of action by perception of action verbs verbs to to understanding understanding of
meaning meaning of
utterances? ? (2) Contribution of MN (2) Contribution of MN activity activity to to recursivity recursivity of
human human language faculty language faculty? ? (3) Contribution of MN (3) Contribution of MN activity activity to to addressee addressee’ ’s representation s representation of
speaker speaker’ ’s meaning s meaning or communicative intention?
The human language faculty
Human communication: an communication: an inferential inferential model model
Motor representations of actions
and lexical lexical semantics semantics
The mirror system system and the evolution and the evolution of
language language use use
activity and communicative intentions communicative intentions
1.1. Why the core Why the core of
the HLF HLF is syntax is syntax
1.2. Why the Why the HLF HLF includes recursive rules includes recursive rules
1.3. The evolutionary function The evolutionary function of
the HLF HLF
1.1. Why the core Why the core of
the HLF HLF is syntax is syntax
(i) Each Each expression expression
natural language is a a pairing pairing of
sound and meaning properties sound and meaning properties, i.e. < , i.e. <phonology phonology, , meaning meaning> >
(ii ii) ) The The < <phonology phonology, , meaning meaning> > mapping mapping for for any complex any complex phrase or sentence phrase or sentence depends depends on
the < <phonology phonology, , meaning meaning> > mapping mapping for for its constituents its constituents. .
(iii iii) ) The syntax is the computational mechanism that The syntax is the computational mechanism that generates generates a a representation representation of
the < <phonology phonology, , meaning meaning> > mapping mapping for a sentence for a sentence from the representation from the representation of
the < <phonology phonology, , meaning meaning> > mapping mapping for for each each of
its constituents constituents. .
1.2. Why the Why the HLF HLF includes recursive rules includes recursive rules
(1a) Colorless Colorless green green ideas sleep furiously ideas sleep furiously
(1b) Chomsky wrote wrote ‘ ‘Colorless Colorless green green ideas sleep furiously ideas sleep furiously’ ’
(1c) Fodor believes that Fodor believes that Chomsky Chomsky wrote wrote ‘ ‘Colorless Colorless green green ideas sleep furiously ideas sleep furiously’ ’
(1d) Pinker doubts that Fodor believes that Pinker doubts that Fodor believes that Chomsky Chomsky wrote wrote ‘ ‘Colorless Colorless green green ideas sleep furiously ideas sleep furiously’ ’, , etc etc. .
(2a) the girl the girl’ ’s s dog dog
(2b) the girl the girl’ ’s friend s friend’ ’s s dog dog
(2c) the girl the girl’ ’s friend s friend’ ’s cousin s cousin’ ’s s dog dog
(2d) the girl the girl’ ’s friend s friend’ ’s cousin s cousin’ ’s roommate s roommate’ ’s s dog dog
(1a-d) and and (2a-d) show (2a-d) show that there is that there is no grammatical no grammatical upper upper bound bound on
length length of sentences of
English. .
If so so, , then there is then there is no grammatical no grammatical upper bound upper bound on
cardinality cardinality of set of
English sentences. sentences.
If so so, , then syntax then syntax of
English must must include recursive rules include recursive rules, , i.e. i.e. rules that can take their own rules that can take their own output as input
( (indefinitely indefinitely): ):
1.3. The evolutionary function The evolutionary function of
the HLF HLF
The evolutionary function of
the HLF HLF is is to to enable any enable any human human infant to infant to acquire her acquire her native native language language L L, i.e. , i.e. tacit tacit knowledge knowledge of
the grammar of
L from her from her perception of perception of linguistic linguistic stimuli, i.e. stimuli, i.e. utterances utterances of sentences of
L made made available available to to her her by speakers of by speakers of L L. .
Problem: : how how was the was the HLF HLF selected given that the selected given that the HLF HLF could only be could only be adaptive adaptive if if there were conspecifics around there were conspecifics around who spoke some natural language who spoke some natural language or
?
The human language faculty
Human communication: an communication: an inferential inferential model model
Motor representations of actions
and lexical lexical semantics semantics
The mirror system system and the evolution and the evolution of
language language use use
activity and communicative intentions communicative intentions
2.1. Decoding Decoding vs.
inferential processes
2.2. The The code model vs. code model vs. the inferential the inferential model of model of communication communication
2.3. The Gricean inferential The Gricean inferential model of model of communication communication and mindreading and mindreading
2.4. The Gricean The Gricean tripartite model of tripartite model of meaning meaning
2.1. Decoding Decoding vs.
inferential processes
A decoding decoding process maps a signal onto its associated process maps a signal onto its associated message by applying the rules of an underlying code. message by applying the rules of an underlying code.
An inferential inferential process derives a conclusion from a set of process derives a conclusion from a set of premises premises in such a way that the former is warranted in such a way that the former is warranted (justified) by the latter. (justified) by the latter.
A conclusion follows from, but is not associated with, its premises. premises.
Nor does a signal justify its message.
2.2. The The code model vs. code model vs. the inferential the inferential model of model of communication communication
On the code model, most if not all of the content of a speaker speaker’ ’s utterance has been coded into, and must be s utterance has been coded into, and must be decoded from, the linguistic meaning of the uttered decoded from, the linguistic meaning of the uttered sentence. sentence.
On an inferential model, the content of a speaker’ ’s s utterance is vastly underdetermined by the coded utterance is vastly underdetermined by the coded linguistic meaning of the uttered sentence. linguistic meaning of the uttered sentence.
2.3. The Gricean inferential The Gricean inferential model of model of communication communication
On Gricean Gricean model, model, task task of
addressee is: : infer infer speaker speaker’ ’s s communicative intention communicative intention from behavioral from behavioral (verbal or (verbal or non- non- verbal verbal) ) cues cues, i.e , i.e task task of
third-person mindreading. .
Bill: Are Are you going you going out?
Jill: : It It’ ’s s raining raining. .
From explicit explicit meteorological meteorological content of J content of J’ ’s s utterance utterance, B , B infers infers implicit implicit content of J content of J’ ’s s response response ( (speaker speaker’ ’s meaning s meaning), ), which which depends depends on
whether B assumes B assumes that that J J likes likes or
dislikes to to walk walk in in rain rain! !
However, , Grice restricted role Grice restricted role of
inferential mindreading mechanisms mechanisms to computation of to computation of implicit implicit content of content of utterances utterances. .
coded linguistic meaning coded linguistic meaning explicit explicit truth-conditional truth-conditional content content
utterance ( (what is said what is said) ) Literal Literal Content Content
linguistically linguistically guided guided saturation saturation (e.g (e.g semantic semantic values values
indexicals) )
implicit implicit content content ( (implicatures implicatures) of ) of utterance utterance Non-literal Non-literal content content
mindreading- mindreading- based inferences based inferences
2.4. 2.4. The Gricean The Gricean tripartite model of tripartite model of meaning meaning
Human Human verbal communication verbal communication makes makes use of use of two two dissociable dissociable kinds kinds of cognitive
processes: : a) a) the the HLF HLF with with a a recursive syntax required recursive syntax required for for combining meanings combining meanings of
constituents into sentential meanings meanings and and b) b) mindreading-based pragmatic inferential mindreading-based pragmatic inferential processes involved processes involved in in determining speaker determining speaker’ ’s s meaning meaning (i.e. communicative intention). (i.e. communicative intention).
The human language faculty
Human communication: an communication: an inferential inferential model model
Motor representations of actions
and lexical lexical semantics semantics
The mirror system system and the evolution and the evolution of
language language use use
activity and communicative intentions communicative intentions
The human language faculty
Human communication: an communication: an inferential inferential model model
Motor representations of actions
and lexical lexical semantics semantics
The mirror system system and the evolution and the evolution of
language language use use
activity and communicative intentions communicative intentions
3.1. Evidence for semantic somatotopic embodied semantic somatotopic embodied representations representations of actions
(SSERA SSERA) ) denoted denoted by action by action words words
3.2. Truth-conditional inferential pragmatic processes Truth-conditional inferential pragmatic processes
3.3. At which level At which level of
meaning do do SSERAs make SSERAs make a a contribution to contribution to the understanding the understanding of
the content of an content of an utterance utterance? ?
a) a) Somatotopy Somatotopy of
motor and premotor and premotor cortex: cortex: location of location of arm/hand arm/hand, , foot/leg representations foot/leg representations b) Connections b) Connections language/ language/ action action systems systems. . c) c) Semantic somatotopy Semantic somatotopy model of model of word processing word processing: : action action words can words can relate to relate to different different body parts to body parts to which which they they are are semantically semantically linked linked (e.g. (e.g. ‘ ‘lick lick’ ’, , ‘ ‘pick pick’ ’, , ‘ ‘kick kick’ ’) )
From Pulvermüller (2005)
a) a) Execution Execution of actions
involving involving distinct body distinct body parts parts b) Passive b) Passive reading reading of
words words for actions for actions involving involving distinct body distinct body parts parts ( (Pulverm Pulvermüller üller, 2005) , 2005)
« « This This “ “semantic somatotopy semantic somatotopy” ” has has provided provided a major argument a major argument supporting the idea that semantic mechanisms supporting the idea that semantic mechanisms are are grounded grounded in in action-perception systems action-perception systems of
the brain » ( » (Boulenger Boulenger et al. (2008) et al. (2008)
Subjects silently read either literal Subjects silently read either literal ( (‘ ‘J.
grasped the cup’ ’) or ) or idiomatic idiomatic ( (‘ ‘J.
grasped the idea’ ’) action sentences. ) action sentences. Brain metabolic Brain metabolic activity was measured activity was measured in in either either short ( short (onset
NP processing processing) or ) or late late (3 s (3 s after end after end of
processing) ) window analysis window analysis ( (Boulenger Boulenger et al., 2008) et al., 2008)
1. Semantic somatotopic embodied representations Semantic somatotopic embodied representations
constitute grasping the meaning
verbs. .
2. SSERA SSERA causally contribute causally contribute to to grasping the grasping the meaning meaning of action
verbs. .
3. Grasping meaning Grasping meaning of action
verbs cause cause activation of SSERA. activation of SSERA.
« The present results The present results support a support a compositional compositional perspective perspective
semantic processing postulating that idiom meaning is computed from the semantics computed from the semantics of constituent
words and from combinatorial combinatorial information.
Semantic somatotopy to to idioms idioms indeed suggests that meaning indeed suggests that meaning aspects of aspects of words words in in these these sentences are sentences are being re-accessed being re-accessed and and combined combined in in the the relatively late relatively late construction of sentence construction of sentence meaning meaning. . » » ( (Boulenger Boulenger et al., 2008) et al., 2008)
« According According to to the embodied the embodied cognition cognition hypothesis hypothesis, , the the motor motor system system is activated is activated because because that that activation activation is causally is causally involved involved in in the analysis the analysis of
the sentence.
According to to the the disembodied disembodied cognition cognition hypothesis hypothesis, , the observed motor the observed motor activation activation is is due to information due to information spreading throughout the spreading throughout the system system » » (Mahon & (Mahon & Caramazza Caramazza, 2008) , 2008)
What is the contribution of contribution of semantic somatotopic semantic somatotopic embodied representations embodied representations of actions (SSERA) to
addressee addressee’ ’s understanding s understanding of
explicit ( explicit (and implicit and implicit) ) propositional propositional content content expressed expressed by by speaker speaker’ ’s s utterance utterance of
the sentence sentence ‘ ‘John John kicked the bucket kicked the bucket’ ’? ?
Free enrichment enrichment + + conceptual strengthening conceptual strengthening
Bob gave Mary his key and she opened the door his key and she opened the door
Explicit content: Bob gave Mary Bob gave Mary his key at his key at t t and and Mary Mary opened the
door at door at t+1 [ t+1 [with with Bob Bob’ ’s s key key] ]
2. Mother Mother to to crying bruised child crying bruised child: : You You are not are not going going to die! to die!
Explicit content: You You are not are not going going to die [ to die [from your bruise from your bruise]. ].
Conceptual loosening+ +metaphor metaphor
My steak steak is raw is raw (explicit content: (explicit content: my my steak steak is undercooked is undercooked) )
The ATM ATM swallowed my card swallowed my card (explicit content: (explicit content: loosening loosening conditions for application of conditions for application of ‘ ‘swallow swallow’ ’) )
Transfer
The ham sandwich sandwich left without paying left without paying (explicit content: (explicit content: the guy the guy who ordered who ordered a a ham ham sandwich sandwich… …) )
I’ ’m m parked parked out back
(explicit content: The owner The owner
…) )
encoded linguistic meaning encoded linguistic meaning explicit explicit truth-conditional truth-conditional content ( content (what is said what is said) ) literal literal meaning meaning implicatures implicatures non-literal non-literal meaning meaning Gricean Gricean minimalist minimalist picture picture encoded linguistic meaning encoded linguistic meaning explicit explicit truth-conditional truth-conditional content ( content (what is said what is said) )
implicatures speaker speaker’ ’s s meaning meaning post-Gricean post-Gricean truth- truth- conditional conditional pr pragmatic agmatic picture picture inferential inferential processes processes inferential inferential processes processes saturation saturation
Speculation! !
The contribution of contribution of semantic somatotopic embodied semantic somatotopic embodied representations representations
denoted by action by action verbs verbs) to ) to lexically encoded linguistic meanings lexically encoded linguistic meanings of action
words seems seems open question.
But I surmise that the mindreading-based inferential surmise that the mindreading-based inferential processes involved processes involved in in computing both the truth- computing both the truth- conditional conditional explicit content explicit content and the implicatures and the implicatures of an
utterance containing utterance containing an action an action verb verb (e.g. (e.g. ‘ ‘I I want want to to pick pick your brain your brain’ ’, , ‘ ‘J.
kicked the bucket’ ’, , ‘ ‘A.
grasped the idea’ ’) ) generate generate ‘ ‘disembodied disembodied’ ’ representations representations of
speaker’ ’s s meaning meaning. .
The human language faculty
Human communication: an communication: an inferential inferential model model
Motor representations of actions
and lexical lexical semantics semantics
The mirror system system and the evolution and the evolution of
language
4.1. Two Two distinct distinct hypotheses hypotheses
4.2. Recursivity Recursivity, , MNs and the MNs and the HLF HLF
4.3. “ “The battle The battle for Broca for Broca’ ’s area s area” ”
activity and communicative intentions communicative intentions
Rizzolatti Rizzolatti et al. (1996) et al. (1996) Buccino Buccino et al. (2003) et al. (2003)
According to to the the direct direct matching matching model, model, MNs enable MNs enable observer
to to understand agent understand agent’ ’s s action by action by directly mapping agent directly mapping agent’ ’s s
’s motor repertoire s motor repertoire: « : « an an action action is understood when its is understood when its observation causes
the
’s motor s motor system to system to ‘ ‘resonate resonate’ ’ » ( » (Rizzolatti Rizzolatti et al., et al., 2001). 2001).
The direct direct matching matching model model was challenged was challenged by Csibra by Csibra’ ’s (2007) s (2007) dilemma dilemma: :
mirroring faithfully duplicates duplicates agent agent’ ’s observed s observed movements movements, , then it fails then it fails to to represent the agent represent the agent’ ’s s goal goal. .
mirroring enables observer to
represent agent’ ’s s goal goal, , then then understanding understanding can can’ ’t t arise arise from from direct direct matching matching of
agent’ ’s s
’s motor repertoire s motor repertoire. .
« Our Our proposal is that the development proposal is that the development of
the human lateral speech circuit speech circuit is is a a consequence consequence of
the fact that the precursor of
Broca Broca’ ’s area s area was endowed was endowed, , before before speech speech appearance appearance, , with with a a mechanism mechanism for for recognizing recognizing actions made by actions made by others
. This mechanism was the mechanism was the neural neural prerequisite prerequisite for for the development the development of
interindividual interindividual communication communication and finally and finally of speech.
We thus view language view language in a more in a more general setting than general setting than one
that sees speech as speech as its complete its complete basis. basis. » ( » (Rizzolatti and Arbib Rizzolatti and Arbib, 1998) , 1998)
Two possible possible interpretations explored interpretations explored by e.g. by e.g. Arbib Arbib (2006), (2006), Fogassi Fogassi & & Ferrarri Ferrarri (2007): (2007):
(1) MN activity activity serves as serves as phylogenetic precursor phylogenetic precursor of
the HLF. HLF.
(2) MN activity activity serves as serves as phylogenetic precursor phylogenetic precursor of
human mindreading inferential ability mindreading inferential ability to to represent agent represent agent’ ’s s communicative intention. communicative intention.
“ “However However, , the flow diagram given the flow diagram given by by Byrne Byrne (2003) shows (2003) shows that that the processing used the processing used by a by a mountain gorilla when preparing mountain gorilla when preparing bundles of bundles of nettle leaves nettle leaves to to eat is clearly eat is clearly recursive recursive. . Gorillas Gorillas ( (like many other species like many other species, , and and not not only mammals
) have the the working memory working memory to to refer their next refer their next action not action not only
to sensory sensory data but data but also also to to the the state of state of execution execution of
some current plan. plan. Hence Hence, , when we refer when we refer to to the monkey the monkey’ ’s grasping and ability s grasping and ability to to recognize similar grasps recognize similar grasps in in
, it is it is a a mistake mistake to to treat the treat the individual grasps individual grasps in in isolation isolation – – the the F5 F5 system system is is part of a part of a larger larger system system that can that can direct direct those grasps those grasps as part of a as part of a recursively recursively structured structured plan plan… … From this From this point of point of view view, , recursion recursion in in language is language is a a corollary corollary of
the essentially the essentially recursive recursive nature of nature of action action and and perception perception…” …” ( (Arbib Arbib, 2006) , 2006)
“Based Based on
these findings, , we postulated that the motor we postulated that the motor system system is organized into is organized into neuronal neuronal chains chains, , each coding each coding for a for a specific specific goal goal and combining different elements and combining different elements ( (motor acts motor acts) )
the action.
Further [ [… …] data on ] data on the monkey parietal and the monkey parietal and premotor premotor cortex have cortex have shown that this shown that this type of type of organization is
valid also valid also for longer action for longer action sequences sequences in in which the same which the same element element of a
chain is recursively recursively involved involved in in different steps different steps
the sequence. . Although this organization is certainly very Although this organization is certainly very basic, in basic, in terms terms of
hierarchical arrangement, arrangement, combinatorial combinatorial power, power, achievement achievement of
meaning and predictive value [ value [… …], ], it it has has much much in in common with the syntactic common with the syntactic structure of structure of language language. .” ” ( (Fogassi Fogassi & & Ferrarri Ferrarri, 2007) , 2007)
Grodzinsky Grodzinsky & & Santi Santi (2008) (2008)
Aphasic Aphasic patients patients with lesion with lesion in Broca in Broca’ ’s area s area presented with English presented with English sentences sentences and pictures and pictures: patients must point to correct : patients must point to correct picture picture. .
Grodzinsky Grodzinsky & & Santi Santi (2008) (2008) In Broca In Broca’ ’s s region effect region effect for for movement movement, not , not reflexive binding reflexive binding
On On the the second second interpretation interpretation of
the hypothesis about about the phylogenetic role the phylogenetic role of
the mirror system in system in the evolution the evolution of
human language use, use, the mirror the mirror system system enables enables an an addressee addressee to to represent the represent the speaker speaker’ ’s s communicative intention. communicative intention.
The human language faculty
Human communication: an communication: an inferential inferential model model
Motor representations of actions
and lexical lexical semantics semantics
The mirror system system and the evolution and the evolution of
language
activity and communicative intentions communicative intentions
5.1. Does Does MN MN activity generate observer activity generate observer’ ’s understanding s understanding of
agent agent’ ’s s prior prior intention? intention?
5.2. Does Does MN MN activity generate observer activity generate observer’ ’s understanding s understanding of
agent agent’ ’s s social social intention? intention?
5.3. Does Does MN MN activity generate addressee activity generate addressee’ ’s understanding s understanding
agent’ ’s s communicative communicative intention? intention?
Does Does agent agent intend intend to affect to affect conspecific conspecific’ ’s behavior s behavior? ?
No! No! Yes Yes! ! non-social non-social social social intention intention intention intention to to perform perform basic action basic action non-basic non-basic =motor =motor action=prior action=prior intention intention intention intention by by conspecific conspecific’ ’s s recognition of recognition of agent agent’ ’s s intention? intention? No! No! Yes Yes! ! non-commu- non-commu- communica- communica- nicative nicative tive tive
Umiltà et al. (2001)
Iacoboni Iacoboni et al. (2005) et al. (2005)
motor motor intention intention to to grasp grasp prior prior intention intention to drink vs to drink vs prior prior intention intention to to clean clean
Dr Dr Jekyll and Jekyll and Mr Mr Hyde may Hyde may have have same motor same motor intention to intention to grasp grasp scalpel, but scalpel, but former has social intention to cure patient, latter to former has social intention to cure patient, latter to enjoy victim enjoy victim’ ’s s pain. pain. Unlikely that MNs Unlikely that MNs in Dr Watson in Dr Watson’ ’s s brain brain can can tell tell the difference between the difference between J J’ ’s s and and H H’ ’s social intentions s social intentions (Jacob & (Jacob & Jeannerod Jeannerod, 2005; Jacob, 2008). , 2005; Jacob, 2008).
Becchio et al. (2008) place
placing into placing into container vs. passing to container vs. passing to partner partner
The experiment shows existence of shows existence of kinematic kinematic differences differences between between ‘ ‘social social’ ’ and and ‘ ‘non-social non-social’ ’ executive executive tasks tasks, , not not that that human human observer
can perceptually perceptually pick pick up up the differences the differences — — let let alone alone via via MN MN activity activity in in observer
’s brain s brain. .
Given that shape of
human hand hand is is perceptually perceptually more more complex than ovoid complex than ovoid container, container, Fitt Fitt’ ’s s law law — — kinematics kinematics of
transitive transitive acts acts (e.g. speed (e.g. speed) ) varies varies with difficulty with difficulty of
task— — may may explain explain data. data.
If so so, , then unclear that experiment is response then unclear that experiment is response to challenge: to challenge: could MNs could MNs in in observer
’s brain discriminate between s brain discriminate between Dr Dr Jekyll Jekyll’ ’s s and and Mr Hyde Mr Hyde’ ’s distinct social intentions s distinct social intentions? ?
good control: test place control: test place into into container container lying lying on a table vs.
place place into into container container hand-held hand-held by by another another. .
Iago intendss
s
Othello to believe that Desdemona has Othello to believe that Desdemona has been unfaithful to Othello by displaying pictures of been unfaithful to Othello by displaying pictures of Desdemona; Desdemona;
Presented with Iago Iago’ ’s s evidence, Othello acquires the evidence, Othello acquires the belief that Desdemona has betrayed him. belief that Desdemona has betrayed him.
But since Iago Iago did not want Othello to recognize his did not want Othello to recognize his social intention social intention I Is
s (to make Othello believe that
(to make Othello believe that Desdemona has been unfaithful to him), Desdemona has been unfaithful to him), Iago Iago’ ’s s social social intention intention I Is
s is not overt and thus not a communicative
is not overt and thus not a communicative intention intention I Ic
c.
.
Forming a a commmunicative commmunicative intention intention I Ic
c: by
: by pointing her pointing her index index finger towards her wrist-watch finger towards her wrist-watch, , Jill Jill expresses expresses her her intention intention that that [Bob [Bob believes believes [ [that she believes that she believes [ [that it is that it is late late]]] ]]]
Jill’ ’s s I Ic
c has 3
has 3 levels levels of
embedding and is thus a 3 a 3rd
rd
metarepresentation metarepresentation. .
If so so, , then then Bob Bob’ ’s s representation representation of Jill
’s s I Ic
c requires ability
requires ability to to form form 4 4th
th
.
Overtness
the content of Jill content of Jill’ ’s s I Ic
c is reflexive
is reflexive in in that she intends that she intends Bob to Bob to come come to to believe believe that she believes that that she believes that it it’ ’s s late late by by virtue virtue of
recognizing her
c.
.
It’ ’s s unlikely that unlikely that MN MN activity activity in in addressee addressee’ ’s brain is s brain is sufficient sufficient to to generate representation generate representation of
speaker’ ’s s communicative intention. communicative intention.
Open question: is is MN MN activity activity necessary necessary for for enabling addressee enabling addressee to to form form a a representation representation of
speaker speaker’ ’s s communicative intention? communicative intention?