Contents - Konrad Lorenz Institute

Sanjida O’Connell/R. I. M. Dunbar
A Test for Comprehension of False Belief
in Chimpanzees
Introduction
Theory of mind (or second
order intentionality) has
come to be the benchmark
for human-like advanced
social cognition. Children
acquire (or develop) this
capacity at around the age
of 4–5 years in a relatively
abrupt fashion (WIMMER/
PERNER 1983; ASTINGTON
1993). Ever since WIMMER/
PERNER’s (1983) classic
study, the false belief task
has become the standard
assay for this. A number of
such tasks (including the
Sally-Ann task and the
“Smartie” task) have come
to be considered as standard
in human developmental
psychology. Although
a very large
number of studies have
used false belief tasks to
study theory of mind and
related abilities in human developmental and abnormal
psychology, there has to date been only one published
study (CALL/TOMASELLO 1999) that has used
this approach with nonhuman animals.
It has, however, been suggested that false belief
tasks may be too anthropocentric for animals to cope
with. Consequently, studies of social cognition in
nonhumans have tended, in recent years, to explore
competences (in particular, the knowledge states of
other individuals, the difference between guessing
and knowing, joint attention and role reversal) that
may be prerequisites for theory of mind (e.g., in great
apes: PREMACK/WOODRUFF 1978; POVINELLI/NELSON/
BOYSEN 1990; POVINELLI/EDDY 1996; POVINELLI et al.
1998; CALL/TOMASELLO 1998; TOMASELLO/CALL/HARE
Abstract
Four chimpanzees, 11 autistic adults and 41 children
aged 3–6 years old were tested on a nonverbal mechanical
analogue of a false belief task under two conditions
(true belief and false belief). The task was first
benchmarked against a conventional false belief task
(the Smartie task) using the children and the autistic
subjects. The children and the autistic subjects exhibited
the classic results on both tasks: all were able to
cope with true belief tasks, but only the oldest children
were able to cope with false belief tasks. Taken as a
whole, the chimpanzees performed significantly better
than the autistic subjects and were not significantly
worse than 4–5 year children on the mechanical analogue
task. However, only one chimpanzee performed
at significantly better than chance levels on both versions
of the mechanical analogue task. We infer from
these results that chimpanzees’ mentalising abilities
are, at best, equivalent to those of human children
around the age at which they just begin to acquire theory
of mind.
Key words
Theory of mind, false belief, chimpanzee, autism.
Evolution and Cognition ❘ 131 ❘ 2003, Vol. 9, No. 2
1998; HARE et al. 2000; in
Old World monkeys: SEY-
FARTH/CHENEY 1990; POV-
INELLI/PARKS/NOVAK 1991,
1992; CHENEY/SEYFARTH/
PALOMBIT 1996; RENDALL/
CHENEY/SEYFARTH 2000).
One difficulty with this
approach is that none of
these studies would meet
the challenge laid down
by the human developmental
psychologists.
None of these tasks, for example,
explicitly requires
an understanding of false
belief for its successful
completion.
An alternative approach
has been the suggestion
that anecdotal evidence
for tactical
deception might fill this
gap. However, this approach
has ultimately
proved to be less compelling
than had initially
been supposed. WHITEN/BYRNE (1988; BYRNE/
WHITEN 1991), for example, collated observations of
tactical deception in the primate literature, and
found a disproportionately high frequency of deception
in chimpanzees and baboons. However, not
all recorded cases of deceptive behaviour may be
second-order intentional, since many could arise
through conditioning and associative learning
(HEYES 1993, 1998). Evidence based on the frequencies
with which animals give food calls, for example,
suggests that animals may not always take the
audience’s state of mind into account: calls may be
correlated with the amount of food present rather
than with another animal’s awareness of the food
(HAUSER/WRANGHAM 1987).