Do Apes have a TOM

Question 1

Evidence relating to apes’ ability to understand the mental states of others wrt:

Answer 1

–Goals & intentions
–Perception & knowledge
–False belief

Question 2

So, do chimps have a theory of mind?

Answer 2

Povinelli- behavioural rules
Tomasello- theory of mind in some sense
•reports of ‘mentalising’ in the wild (anecdotes)
•Evidence that they understand: goals/intentions and seeing=knowing
•BUT: failure to solve FB tasks in lab (until 2016!)
•Mixed evidence
•Difference for
–Competition vs cooperation ???
•Different ways to interpret the results

Question 3

Authors claim

Answer 3

Great apes anticipate that other individuals will act according to false beliefs

Question 4

Competing explanation:

Answer 4

apes used knowledge of abstract rules — specifically, that people tend to look for objects in the place they last saw them

Question 5

Unique to humans?

Answer 5

possibility:
-chimpanzee’s mind seems similar to ours precisely because it is similar

2nd possibility:
- We cannot help distorting the chimpanzee’s mind, recreating it in our own image

Question 6

Premack and Woodruff (1978): Does the chimpanzee have a theory of mind?

Answer 6

• Chimp offered correct solutions to an actor’s problems

* Suggesting she could infer the actor’s intentions

Question 7

Woodruff & Premack (1979)

When human cooperated with chimpanzee in finding a goal (hidden incentive):

Answer 7

•chimpanzees able to produce and comprehend behavioural cues which conveyed accurate locational information

When human and chimpanzee competed for the goal:
•chimpanzees learned to withhold information or mislead the recipient
•and to discount or go against the sender’s own misleading cues
But only after A LOT of training!

Provides evidence of a capacity for intentional communication / deception

Question 8

Do chimps have a theory of mind

The debate

Answer 8

Povinelli camp
•Chimps do not reason about others’ beliefs, or any other mental states
•same behaviours, but not same underlying psychological mechanisms

Tomasello camp
•Chimps have ToM in some respects, but not in others
•No evidence whether they understand false beliefs
•BUT: chimps understand:
–goals and intentions, and
–perception and knowledge
of others

Question 9

Povinelli camp

Answer 9

• Chimps do not reason about others’ beliefs, or any other mental states
• same behaviours, but not same underlying psychological mechanisms

Question 10

Tomasello camp

Answer 10

Chimps have ToM in some respects, but not in others
•No evidence whether they understand false beliefs
•BUT: chimps understand:
–goals and intentions, and
–perception and knowledge
of others

Question 11

Do chimps have a theory of mind

Behavioural abstraction Hypothesis

Answer 11

•Understand only surface-level of behaviour and form behavioural rules
•‘BAH’ posits that chimpanzees:
–make predictions about future behaviours that follow from past behaviours, and
–adjust their own behaviour accordingly.

Question 12

Behavioural Abstraction Hypothesis

Answer 12

•Understand only surface-level of behaviour and form behavioural rules
•‘BAH’ posits that chimpanzees:
–make predictions about future behaviours that follow from past behaviours, and
–adjust their own behaviour accordingly.

Question 13

Beyond behavioural rules

Answer 13

•Chimps highly social animals – need to anticipate what others do
•Observing previous behaviour and deriving set of behavioural rules enables behavioural prediction
•BUT: Inferring states not only in previously observed situations,
but also in novel situations
•Need to anticipate actions based on goals and intentions

Question 14

Call and Tomasello 2008

Understanding goals and intentions

Answer 14

➢ Chimps show understanding of goals or intentions

➢ Imitation studies contradict Povinelli’s behavioural abstraction hyp

Question 15

Buttelman et al 2007

Understanding goals and intentions

Answer 15

• chimps imitate rationally
• Imitated E’s novel action when he seemed to do it intentionally but NOT when this was due to a physical constraint
• chimps understand other’s goals and intentions

Question 16

Altruistic helping requires

Answer 16

• Cognition = understanding of another’s goals

* altruistic motivation = no benefit/costly

Question 17

Altruistic helping

Warneken and Tomasello 2006

Answer 17

•Study 1: 18mos infants (N=24) 
Study 2: 36-54mos chimps (N=3)
•Procedure: 
10 situations, 4 categories
1.Out-of-reach
2.Access thwarted by physical object
3.Achieving wrong result
4.Using wrong means
3 request phases 
(10s focus only, 10s alternate gaze, 10s verbalise)

Question 18

Altruistic helping
Warneken and Tomasello 2006
Infant data

Answer 18

• children and chimps both willing to help without reward or praise
• Chimps helped more in reaching tasks than other tasks (salient cue?)
• differ in ability to interpret others’ need for help?
• Methodological note: cooperation vs competition

Question 19

Understanding others’ perception and knowledge

Important to know not only the goals of another but also:

Answer 19

•What s/he can see
•What s/he knows
 will help determine what s/he does.

Question 20

Povinelli and Eddy 1996

Can chimps follow gaze

Answer 20

•chimp looks to spot behind her
•chimp tries to look behind screen
–target cannot be what I cannot see

Question 21

Understanding perception
Negative evidence
Povinelli and Preuss 1995
Povinelli and Eddy 1996

Answer 21

Chimps beg for food from blindfolded human

Begging is indiscriminate

Question 22

can chimps appreciate what others ‘see’?

Answer 22

•Chimps experts at noticing finest subtleties of eye movements and gaze directions
•possess and learn rules about visual perception
•BUT:
these rules do not necessarily incorporate the notion that seeing is “about” something
–oblivious to psychological distinction between begging from blindfolded carer vs non-blindfolded
•Chimps cannot reason about seeing?

Question 23

Pavinelli and Eddy 3 explanations

Answer 23

1. general delay in psychological development in chimpanzees
2. chimpanzees may possess a different (but nonetheless mentalistic) theory of attention
3. subjective understanding of visual perception may be unique to humans

Question 24

Kaminski et al 2004
Understanding perception
Positive evidence

Answer 24

• Chimps begged more when they were being watched

* Sensitive to both body and face orientation but not eyes

Question 25

Co-operation vs competition

Answer 25

• Negative results in the lab required co-operative communication with humans
• Cf. informal observations of ‘mentalising’ in the wild involved competition with conspecifics

Question 26

Understanding knowledge and perception
Positive evidence
Hare, Call & Tomasello 2001

Answer 26

Competitive paradigm

chimpanzees can reason about others’ knowledge on the basis of what others have / have not seen

Question 27

Two interpretations

Answer 27

Behavioral Abstraction
Mental-state attribution
•“He was present and facing the food when it was placed where it is now therefore he is likely to go after it”
•“He was not present when the food was placed where it is now therefore he is less likely to go after it”
Mental-state attribution
•“He was present and facing the food when it was placed where it is now so he saw the food placed and currently knows where it is therefore he is likely to go after it”
•“He was not present when the food was placed where it is now so he didn’t see it, therefore he doesn’t know.. therefore he is less likely to go after it”

Question 28

Hare et al 2006
Understanding perception and knowledge
Positive evidence

Answer 28

•Perceptions differ:
–need to distinguish between own and other’s vision
(seeing = knowing)
•chimps show visual and auditory perspective taking

Question 29

Hare et al 2006

Answer 29

Visual perspective taking

Question 30

Melis, Call & Tomasello (2006)

Auditory perspective taking

Answer 30

• In the presence of a human competitor, chimps preferred to reach through a silent rather than noisy tunnel
• Suggests they are sensitive to what others can hear
• Are able to manipulate the auditory perception of a competitor

Question 31

Call and Tomasello 2008

Answer 31

Studies on chimps and human infants knowledge of perception and knowledge
➢Do this without past experience of these situations (so no rule learned)
➢contradict Povinelli’s behavioural abstraction hyp

Question 32

Call and Tomasello, 1999

A test for FB understanding no.1

Answer 32

1.man watches as treat 
hidden under one of two 
cups; chimp can’t see
2.man leaves
3.cups are swapped
4.man returns and points 
to one cup
5.chimp single chance to 
retrieve
-> chimp scores if looks under cup man didn’t point to

Question 33

Test for FB understanding number 2

Answer 33

• Testing monkeys in the wild

* Participants opportunistically sampled by searching the island

Question 34

Monkeys represent others knowledge but not Their beliefs

Marticorena et al 2011

Answer 34

Experiment 1
Used a Violation of Expectancy method similar to Onishi & Baillargeon (2005) with rhesus monkeys
Looked for longer when actor fails to look for object in correct location when she is informed
Experiment 2
False belief continued
No difference in looking time

Question 35

Results
Marticorena et al 2011
Monkeys represent others knowledge but not their beliefs

Answer 35

•Findings suggest they can represent whether the actor is knowledgeable or ignorant
•However, they did not expect the actor to search in the wrong location in line with their (false) belief
 Monkeys can represent the knowledge and ignorance of others but not their beliefs – in contrast to 15mo infants!

Question 36

Test for FB understanding number 3

Krupenye et al 2016

Answer 36

Latest evidence using eye-tracking.
Used anticipatory gaze paradigm based on Southgate et al. (2007)
•Authors’ claim: Great apes anticipate that other individuals will act according to false beliefs
•Competing explanation: apes used knowledge of abstract rules — specifically, that people tend to look for objects in the place they last saw them