Getting Aped by Apes


The Guardian recently published an article, “Apes can guess what others are thinking—just like humans, study finds.” The story is based on an experiment conducted by Christopher Krupenye (Duke University) and Fumihiro Kano (Kyoto University) that purports to show that apes can predict what a person will do on the basis of that person’s false belief.

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(To have a “false belief” is to believe something about reality that is not actually the case.) Up until now, no study had demonstrated that apes had this capacity. As the researchers explain, this predictive capacity expresses an awareness of the determinative relationship between an agent’s beliefs and actions. To anticipate another’s acting on a false-belief, one must be interpreting the action, not on the basis of any “external” factors, but rather on the attribution to that subject of some unobservable mental state (i.e., a belief). Doing so means one has a “theory of mind” and can potentially see others as possessing an “inner, unobservable life.” In this post, I am going to challenge the need for a “theory of mind” to explain the success of apes and human beings in the anticipating the actions of others in light of some awareness of their false belief.

In the present study, researchers tested the predictive capacity of apes by tracking their eye-movement while they watched a video of a human being searching for a gorilla. If their eyes fell on the location of the gorilla that the man knew from a previous encounter—but which the gorilla, in the meanwhile, had left—the apes were counted as having correctly anticipated the action of the man on the basis of their apprehension of his false belief. Is this enough to conclude, as the researchers do, that apes “solved the task by ascribing a false-belief to the actor, challenging the view that the ability to attribute reality-incongruent mental states is specific to humans,” i.e., that apes have a “theory of mind?” I think we have an explanatory gap here. What warrants the move from the anticipatory eye-movements of the ape to their “ascribing” a false-belief and “attributing” a mental state to the agent in question?

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According to Merriam-Webster, “attribute” means “to explain by indicating a cause” while “ascribe” means “to refer to a supposed cause, source, or author.” Each definition presupposes some awareness of the concept of a “cause” and the need for an explanation of some thing or event by reference to its “cause.” With these definitions in mind, it is not clear to me how an ape’s visual attention to a particular location counts as an attribution or ascription of false-belief. The ape is not “attributing” or “ascribing” anything, but rather looking at events on a video screen. The researchers are using the terms “ascribe” and “attribute” to explain why the ape’s eye-movements focus on certain locations as opposed to others. Indeed, the researchers are attributing an act of attribution to the apes on account of their eye-movements. Is this how human beings “attribute” false beliefs to others?

Consider the same experiment with a language-using adult. The researchers take note of the eye movements, which tracks the location the searcher is expected to engage based on his false belief. The researcher says to the subject, “I see from your eye movements that you were attributing a false belief to that man chasing the gorilla.” The subject responds, “Yes, I assumed he would look where he last saw the gorilla.” But suppose the researcher then asked, “So you made an inner act of attributing a false-belief to the man that caused you to look at this particular location?” I am doubtful that the subject will respond in the affirmative. (If you don’t believe me, try showing the video to a friend and asking the same question, or try to recall for yourself whether, when watching the video, you made an “inner act of attributing a false-belief.”)

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Indeed, it’s possible that our subject’s eye-movements were preceded by no deliberation at all. When our subject responds, “Yes, I assumed he would look where he last saw the gorilla,” she is explaining her eye-movements rather than reporting what went on in her head. We could say that she, unlike the ape, is able to attribute to herself an act of attribution, but this is not the same as her actually having an “inner act of attribution.” We do have such acts, of course, as this famous scene from Indiana Jones and the Last Crusade demonstrates. Paradigmatically, however, the attribution of intention, desire, or belief comes in the form of an explanation, an attempt to make a certain action intelligible to a curious interlocutor. In such cases, we often attribute to ourselves an intention, desire, or belief that was not “in our head” during the action. As Thomas Aquinas famously remarked, when walking home, one need not be thinking about one’s final destination at any step of the way (ST I-II 1.6 ad 3). So, an explanation of an action by means of an attribution of some intention, desire, or belief is not necessarily a report on an individual’s “inner” mental state.

I’m not suggesting that we never report what goes on in our head. The famed neurosurgeon, Wilder Penfield, recounts many anecdotes of people reporting what he was doing “in” their brain via neural stimulation in his classic study Mystery of the Mind. Nor am I suggesting that we never have deliberate eye-movements. After all, we sometimes deliberately look someone in the eye when apologizing. I am suggesting that an appeal to our knowledge of someone’s false-belief as an explanation of action does not necessarily entail that one actually had an inner mental act of attribution of false-belief. For this reason, I see no warrant for the claim that the success of the apes in this study demonstrates that they engaged in a mental act of “attribution” or “ascription” of false-belief.

In making this claim, I am not denying that the eye-movements of these apes presuppose some awareness of an agent’s false-belief—otherwise we would not be able to explain why the eye-movements of apes and human beings consistently track the “false” location. What I am denying is that this awareness—in both humans and apes— necessarily involves a deliberate act of attribution or ascription of a false-belief. (I use the qualification “deliberate” because it is nonsensical to describe an act of attribution as “accidental,” as if one could “accidentally” explain something.) And because I think a human being participating in this study would not “report” a deliberate, inner mental act of attribution, I am skeptical of “attributing” such an inner, mental act to an ape participant.

The takeaway from this post should be that a “theory of mind” is not needed to explain the success of either apes or humans on false-belief tasks. On this score, I am in fundamental agreement with the famed primatologist Frans de Waal, who concluded that the study “may help us move away from the prevailing assumption that theory of mind relies on a cognitive simulation of what is going on in the heads of others.” I would go further, however. We should ask whether a “theory of mind” is adequate to explain human, much less non-human, cognition and action. Keep this in mind whenever you are tempted to think we are being “aped” by apes.