Carpenter lecture 4 communication

Gestural communication
in children and
chimpanzees

• Humans communicate with each other in unique ways.
• Most obviously, linguistically, with socially learned,
intersubjectively shared symbols
• But also gesturally. Many of the most important gestures
humans use - e.g., for greeting or leaving, for threatening or
insulting, for agreeing or disagreeing - are also socially learned,
intersubjectively shared, symbolic conventions that vary across
cultures in much the same way as linguistic symbols.

• This requires both ‘mindreading’ (theory of mind) and the
ability/motivation to cooperate with others.

Tomasello (in press); Tomasello, Carpenter, & Liszkowski (submitted)

Outline
• Development
• Theoretical issues
• Pointing
• Pointing basics
• Infants
• Apes
• Children with autism

Development of communication in infants
Milestone Average Age (months)
Babbling (e.g., bababa) 7
[?] Joint attention, anticipatory smiles by 8-9
Comprehends a word 9
Showing 9-10
Giving 12
Pointing 12
Comprehends 50 words 13
Produces first word 13 (range 9-16)
Produces 10 words 15 (range 13-19)
Produces word combinations 21 (range 18-24)
Adamson (1996); Carpenter, Nagell, & Tomasello (1998)

Development of communication in infants
Milestone Average Age (months)
Babbling (e.g., bababa) 7
[?] Joint attention, anticipatory smiles by 8-9
Comprehends a word 9
Showing 9-10
Giving 12
Pointing (ToM, coop., complexity) 12
Comprehends 50 words 13
Produces first word 13 (range 9-16)
Produces word combinations 21 (range 18-24)
Adamson (1996); Carpenter, Nagell, & Tomasello (1998)

Theoretical debate
• ‘Lean’ versus ‘rich’ interpretations of gestures in 12-month-
old infants and apes
• social-cognitive understanding:
• lean: just trying to achieve certain behavioral effects in others
(see others as causal but not mental agents; influence behavior)
• rich: attempting to influence the intentional/mental states of others
(transfer a mental message; influence mind)

• motivation:
• lean: to achieve own goals (e.g., get object or attention from
adult)
• rich: also for others (inform, help, share); cooperative structure


Pointing basics
• In itself, pointing is nothing. When faced with a pointing
finger, most animals and very young infants simply stare
at the finger.

• Even understanding the directional nature of pointing is
not enough to comprehend a full communicative act. It
is possible to follow someone’s point but not know what
he means by it. To illustrate:


Tomasello, Call, & Gluckman (1997);
see Call & Tomasello (2005) for a review

• In a food finding
context, a human
points to one of two
opaque containers.

 Apes follow the
point - but then
choose randomly.

• Why?
• Either apes don’t know what E was directing their
attention to (exactly what E was referring to), or else they
don’t know why E was directing them to it (what E’s
motive was).
• what: precise referent is not bucket as physical object but bucket
as location of food
• why: not just to show bucket, to inform them of the location

• Pointing can be incomprehensible without some form of
shared context or ‘common ground.’ To correctly identify
the referent, the recipient needs to assume the point is
relevant to something she and the pointer share.


Importance of shared context
(what + why)

• Shared context can help you determine what the
other is pointing to (and often why)

• Expressions of attitude can also help you
determine why.

Attitude (observable cue to motive – why?)

More pointing basics
• A pointer thus combines an act of reference with an
expression of motive, with the desire that the recipient
attend to both of these, and from this infer the pointer’s
overall intention - what the pointer wants the recipient to
do - by finding some relevance to their common ground.

 involves understanding of intentions and shared experience

• This entire process is inherently collaborative:
communicator and recipient work together to identify the
intended referent, as well as the pointer’s larger intention
(Clark, 1996).


• Cooperative communicative acts involve an additional type
of intention as well: a communicative intention or intention
about the communication specifically (Grice, 1957; Sperber &
Wilson, 1986).

• When a person points to a tree for me, she not only wants me to
notice the tree, she also wants me to notice her desire that I notice
the tree. This additional tier is necessary to instigate in me the
kinds of relevance inferences required to identify the
communicator's reason for communicating (her motive).
• if instead she leans back and I see the tree, I don’t need to make those
kinds of inferences


She intends that I attend to X (and wants us to know this
together) for some reason relevant to our common
ground.


She intends that I attend to X (and wants us to know this
together) for some reason relevant to our common
ground.

Apes do have some understanding of others intentions and
attention. Either:
1) do not have a joint attentional frame (common
ground) with the human that enables them to
determine reference; (She’s pointing to the bucket. I’m
searching for the grape – I don’t care about the bucket.)
2) do not understand the communicative intention ,
i.e., that the human wants them to know that she has
an intention with respect to them; or
3) do not understand the informing/helping motive
(cooperative intention) of the human in this situation.


Complexity of pointing: Adult examples
Standing in line at the bank, one person points for another in the adjacent
line to a scarf she has inadvertently dropped on the floor. Gloss: "You
dropped that."
On a river bank next to a noisy waterfall, a person hands me a book up (I
am on top) for safekeeping as she climbs up. She points to the tip of a
pencil protruding from the book. Gloss: "Don't let this fall out".
In a bar, to a bartender, a person simply points to his empty shot glass.
Gloss: "I'll have another".
In airplane, I am standing up idly near the bathrooms. A man
approaches and points to the bathroom door with a quizzical expression.
Gloss: "Are you waiting for the bathroom?"
One person to another in line, informing them of a gap in the line ahead
of them. Gloss: "Hey. Move up."
I approach my parked car and a truck has it blocked in. I look to the
driver with an apologetic expression and point to my blocked-in car.
Gloss: "Sorry, but you have to move to let me out".

Tomasello, Carpenter, & Liszkowski (submitted)

Complexity of pointing: Infant examples (11-13 months)

As Dad prepares to leave J points to door.
Mom pouring water; J points to his glass to tell her to pour him some.
Mom tells J not to touch her hot teacup; later he points to it and says "No."
Mom asks where J got something. J points out the door, saying “There.”
J watches as Dad arranges Christmas tree; when Grandpa enters room J
points to tree and says "Oh!"
J bumps his head. When Mom comes he points to offending object.
Points to sky to sound of airplane out the window (can't see).
After eating points to bathroom anticipating going to wash hands.
Mom is looking for magnet. L points to basket of fruit it is hidden in.
L pulled lamp halfway off wall. Dad comes in, L points to show what
happened.
T leads Dad around house by pointing, until they find Mom.

Carpenter et al. (in preparation); Tomasello, Carpenter, & Liszkowski (submitted)

Complexity of infant pointing
• Many motives, meanings
• important because classically infant pointing was thought to
have only two main functions:
• imperative: to request objects
• declarative: to share attention and interest to objects or events
• ape ‘pointing’ apparently only imperative

• important because classically infant pointing is thought to have
only two main functions:
• ape ‘pointing’ only imperative (?)

• Absent referents
• important because this is taken to be a hallmark of uniquely
human language; also evidence that it is communication on a
mental level

• ape ‘pointing’ only imperative (?)

mental level

• Natural observations are interesting but experiments are
needed.

Experiments

• Common ground
• Informative (helping) motive
• Communicative intention

Common ground
• Infants begin participating in joint attentional
engagement by 9 months (more on that tomorrow)

• By 14 months, they can use joint attentional
frames/common ground to interpret others’ points.

Behne, Carpenter, & Tomasello (2005)

• 14- to 24-month-olds

• Following a visible
‘hiding’ warm-up, E hid
a toy in one of two
opaque containers.

• E indicated the toy’s
location by pointing or
gazing at the correct
container. Mean % correct responses +/- SE
100
90
80

 Even the youngest
70
60
Gaze
infants chose the 50
40
Point

correct container more 30

often than chance.
20
10
0
14 months 18 months 24 months

Liebal, Behne, Carpenter, & Tomasello (in preparation)
• 18-month-olds

• In each of two Common Ground
conditions, infants participated in
a different shared activity
(cleaning up or stacking) with an that
adult
adult, then that adult pointed
pointed
(“There!”) at a target object.

• In a third, No Common Ground
condition, to test whether infants
a
were really using common different
ground, infants shared a frame adult
with one adult and then a pointed
different adult pointed (“There!”).

Liebal, Behne, Carpenter, & Tomasello (in preparation)
• Even though the adults pointed in
exactly the same way in each
condition, infants interpreted the
point differently depending on the
common ground they shared with
the adult:

 In the Common Ground
conditions, infants’ responses
were appropriate to the previous
shared activity.

 In the No Common Ground
condition, they continued the
previous activity less than in the
corresponding Common Ground  Infants used their common
condition, instead mostly ground with specific partners to
interpreting the new adult’s point interpret their partners’ gestures.
as a declarative.

• imperative : to request objects
• declarative : to share attention and interest to objects or events

• Infants do point imperatively and declaratively (more on this
tomorrow). They also point to inform others of things they do not
know.

Liszkowski, Carpenter, Striano, & Tomasello (2006)

• 12- and 18-month-olds

• Infants watched E repeat an
action (e.g., punching holes)
with a target object.

• The target and a distractor
object were displaced.

• E began looking around. 0.45
Target Distractor
0.4
Proportion of trials with point

Infants pointed to inform the 0.35

adult about the location of the 0.3

object she was looking for. 0.25

0.2

0.15

0.1

0.05

0

12 months 18 months

• Common ground
• Many motives, meanings, including to inform others.
mental level

Liszkowski, Carpenter, & Tomasello (submitted)
Referent Present Phase
• 12-month-olds Attend Event Attend Screen
• A puppet appeared; E
attended and emoted
(positively or neutrally) either
to it or to the blank screen on
the other side. After the
puppet disappeared, E
turned to the infant.
 In the first phase, infants Referent Absent Phase
pointed more often when E
attended to the screen than
to the puppet (to inform).
 Infants also pointed when
the referent was absent,
differentially depending on
how E had reacted before.

• Common ground
• Many motives, meanings, including to inform others.
• Understanding of communicative intention (tree example)

Behne, Carpenter, & Tomasello (2005): control condition

• E ‘pointed’ or gazed to
the correct container but
in a distracted, non-
communicative manner.

 In this condition,
children performed at
chance levels.

Infants
 Communication on mental instead of behavioral level 
• Evidence (already reviewed) of understanding of attention
and intentions by 12 months
• Absent referents (Liszkowski et al., submitted)

• Misunderstandings
• Shwe & Markman (1997): when 2½-year-olds request
something from an adult, and the adult misunderstands but
gives them what they wanted anyway, they still attempt to
correct the misunderstanding. This suggests that they had
both the goal of getting the object and the goal of having the
adult understand their message or communicative intention.

 Prosocial motivations 
• to achieve own goals, of course, but also prosocial: to inform
(help), to share.

Apes
 Communication on mental or behavioral level ?
• Evidence (already reviewed) of understanding of perception

and goals - but not attention and intentions (?)
• not much (if any) gesturing about absent referents in

non-language-trained apes


No prosocial motivations 
• to achieve own goals only; no evidence of gesturing to

inform (help others, without benefit for themselves) or
share (tomorrow).

Children with autism
 Communication on mental or behavioral level ?
• Evidence (already reviewed) of understanding of perception
and goals - but not attention and intentions (?)
• ?


No prosocial motivations 
• probably to achieve own goals only; no evidence of
gesturing to share (no studies on informing).

• Also general difficulties with communicative intentions
(e.g., common ground, ‘language of the eyes’; see Sabbagh, 1999,
for a review).

Summary
• By 12 months, when they first begin pointing, infants
already show the basics of uniquely human
communication, supporting the ‘rich’ view.
• Support for the social-pragmatic view of language acquisition
(Bruner, Tomasello, etc.)

• More studies are needed, but so far, ‘leaner’
interpretations of communication in apes and children
with autism fit best.

 Hare and Tomasello (2004) hid food in one of two buckets and then, in one condition,
pointed to the bucket containing the food in order to inform the ape where it was. In this case, as
in previous studies, the apes searched randomly. The novelty was in the second condition. Here
E began by establishing with each ape a competitive relationship over the food, and then later
reached toward one of the two buckets in a vain attempt to open it (the reaching was impeded).
Now, surprisingly, even though the superficial behavior of the human was highly similar to that in
the pointing condition - in both cases the human stretched out his arm toward the correct location
- the apes in this condition suddenly knew where the food was. In this case, the apes had to
discern the goal of the human - to get into that bucket - and then infer why he wanted to do this:
because there is something good inside. This cognitive process is quite complex on its own
terms, but the key point is that it includes none of the crucial elements of shared intentionality
from our analysis of the interpersonal structure of pointing. The apes' understanding of the
human's reaching is of individual goals or intentions toward things, not communicative goals or
intentions toward themselves. There is thus no question of a joint attentional frame or common
ground, or of communicative or referential intentions, or of any assumptions of helpfulness or
other interpersonal motives.
 Following Tomasello et al. (2005), we may thus attempt to characterize the essential
elements in the comprehension and expression of human pointing as a communicative act by
viewing them from the perspective of shared intentionality. Whereas apes' understanding of the
goal of a reaching person is essentially an act of individual cognition, humans' understanding that
others are pointing out things for them because of their presumed relevance to some common
ground or joint attentional frame is an act of interpersonal cognition involving shared attention

and knowledge, along with some motive for helping or sharing with others.

Mean % correct responses +/- SE

100
90
80
70
60
Gaze
50
Point
40
30
20
10
0
14 months 18 months 24 months

Infants

Chimpanzees
 Infants pass this test.

Carpenter lecture 4 communication

Recommended

Recommended

More Related Content

Similar to Carpenter lecture 4 communication

Similar to Carpenter lecture 4 communication (20)

Recently uploaded

Recently uploaded (20)

Carpenter lecture 4 communication

Editor's Notes