Daniel Horschler Abstracts

Daniel Horschler

Ph.D. Candidate

Cognitive Science GIDP

26th International Conference on Comparative Cognition

Melbourne Beach, Florida

April 10-13, 2019

Whether, and to what extent, animals understand the mental states of others is a longstanding question in comparative cognition. Researchers have proposed that non-human primates form ‘awareness relations’ to link objectively true information to other minds, as opposed to humanlike representational relations tracking ignorance or belief states. We present the first explicit test of this hypothesis by examining when monkeys’ understanding of others’ knowledge falters. Monkeys watched an agent observe food being hidden in one of two boxes. While the agent’s view was occluded, either the food moved out of its box and back into it, or the box containing the food opened and immediately closed. Monkeys looked significantly longer when the agent reached to the incorrect compared to the correct location after the box’s movement, but not after the food’s movement, suggesting that monkeys did not expect the agent to know the food’s location when it moved while the agent could not see it, but did expect the agent to know the food’s location when only the box moved. Our findings support the hypothesis that monkeys reason about others’ knowledge using ‘awareness relations’ which are disrupted by arbitrary manipulation of a target object while an agent cannot see it.

Abstract for Lay Audience

My talk entitled “Do non-human primates really represent others’ ignorance? A test of the awareness relations hypothesis” will address how monkeys understand what others know based on what they have seen, one aspect of what cognitive scientists refer to as “theory of mind” (the ability to understand that others have knowledge, thoughts, or beliefs that are separate from one’s own). The extent to which monkeys have a theory of mind is an important open question in the field of comparative cognition, and research in this area can help to inform us about not only how other animals see the world, but also about how humans have evolved to think in the ways that we do. 

More specifically, my findings are notable for two main reasons. First, my research shows that monkeys mentally represent the knowledge of others using a simple heuristic which allows them to correctly make inferences about others’ behavior most of the time but leads to inaccurate predictions of others’ behavior in situations that had not previously been tested. Second, my research shows that primates’ failure to correctly predict others’ behavior when others have false beliefs (i.e. when someone believes something is true about the world when it actually is not) in a number of highly cited studies may be due to this heuristic. In these classic false belief tasks, a false belief is induced in an agent when a primate watches some object (usually a piece of food) change hiding locations (e.g. move out of one box and into another) while the agent is not able to see it. The result is that the primate knows where the food actually is, but the agent still believes it to be in its previous hiding place, because he or she did not see it move to the new location. Classically, failure to predict the agent’s behavior (i.e. searching for the food where he or she believes it to be rather than where it actually is) has been attributed to an inability to conceptualize the mismatch between what is objectively true about the world and what the agent believes. My results suggest that performance in such tasks could be due to a much simpler mechanism. Namely, any movement of the object while the agent cannot see it may disrupt the subject’s initial attribution of awareness of the object’s location to the agent. In other words, when the object moves in any way while the agent cannot see it (even if the object moves directly back to where the agent witnessed it being hidden previously), the primate no longer has any expectation about the agent’s belief regarding the object’s location. This is an important finding because it shows that in previous studies, the fact that the object changes hiding locations may be entirely irrelevant – instead, it seems that when the object changes states in even arbitrary ways, primates still have incorrect expectations of the agent’s behavior. 

Researchers have argued that a true understanding of false beliefs is hallmark of uniquely human cognition. My findings will help to advance the field of comparative cognition by showing that the evidence this argument is built on may be flawed in an important way and could lead to new and better-controlled tests of false belief understanding in other animals.