Much effort has been made in cognitive science to understand the extent to which apes have theory of mind. Theory of mind, Gazzaniga describes, was first put forward by Premack and Woodruff, and is “the ability to observe behavior and then infer the unobservable mental state that is causing it” (2008). Humans develop it in full by the age of four.
The false-belief task, some researchers believe, is important in demonstrating theory of mind, so Call & Tomasello (1999) put 4-5 year old children, chimpanzees, and orangutans to the test. In this task, the subject is not allowed to watch as adult A hides a reward (a sticker for children, and food for apes) underneath one of two containers, while adult B watches. The subject is allowed to watch as adult B marks the container he or she believes to contain the reward. In this case, the subject would always choose the marked container to uncover the reward. However, in the false belief trial, Adult B watches the hiding, but then leaves for a period of time, during which the subject watches Adult A switch the containers. After Adult B comes back in the room, marking the container which he or she believes to hold the reward (the wrong one, of course), the subject must choose which container has the reward. The results of this study are that the 4 and 5 year old children recognized that Adult B has a false belief, and picked the correct container that Adult B had not marked. The apes, however, picked the container Adult B had marked. They did not recognize that Adult B had a false belief.
This experiment is an especially good measure of false belief, because 1) it is nonverbal, so apes can participate in it, and 2) it involves tasks that the apes have already mastered. Some past studies on false belief had produced ambiguous results because it was not certain whether the apes were so focused on trying to perform the task that they could not even begin to attempt to understand the mind of another.
The researchers ultimately concluded from this study that apes do not have much of a theory of mind, at least in the sense of understanding that others may hold false beliefs. Though, Gazzaniga brings up the point that theory of mind is certainly more than just being aware of false belief.
A crucial problem with the experiment is that it leaves out the possibility that apes do have theory of mind, but with conspecifics, not with humans. Humans, certainly, cannot accurately infer the mental state of another animal; our epistemology is staunchly anthropocentric. Just the same, it may be very difficult for an ape to infer something about the state of a human mind. Thus, this study does not really prove that apes have no theory of mind in regards to their peers. Call & Tomasello try to buttress the validity of human theory of mind, and thus its reliability as a standard for all, by pointing out how humans so readily attribute mental states not only to animals but to inanimate objects. However, their argument collapses: there is a good chance that humans are attributing wrong mental states to animals and inanimate objects. Therefore, the apes may also be attributing a wrong mental state to Adult B, not due to deficit theory of mind, but due to inaccurate theory of mind.
Whether apes do have some degree of theory of mind or not, and whether or not humans even have the ability to detect it and describe it, are not the only important issues broached by this experiment. The other is what it really means for our understanding of the human mind to be able to compare human and ape cognition. It is especially notable that, as Gazzaniga points out, younger children (at least below the age of 2), autistic children, and apes all perform similarly (that is, badly) on the false-belief task. It is definitely an interesting notion that ontogeny recapitulates phylogeny, that at one point in the womb humans have gills like a fish, and by the age of 2 they have similar cognition to that of an ape. The continuum between humans and animals is evident: humans are surely animals that are higher-functioning. In addition, however, the idea that autistic children and apes are on a similar social level is consequential. How a human person can be defined is called into question, as the autistic child, by the theory of mind classification, loses something distinctive to humanity.
Gazzaniga, M.S. 2008. Human: The Science Behind What Makes Us Unique. Harper Collins:
Call, J., and M. Tomasello. 1999. A nonverbal false belief task: The performance of children and great apes. Child Development 70:381-95.
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