Do Chimpanzees Reason about Belief?

For almost 40 years, psychologists and philosophers have been devising experiments and testing chimpanzees on the question first asked by Premack and Woodruff in 1978: “Does the chimpanzee have a theory of mind?” With this question, they meant to ask whether chimpanzees do what they assumed we do, namely, attribute beliefs and desires in order to predict behavior. This capacity is known as mindreading or theory of mind. After 30 years of chimpanzees failing all the tests we put to them, some researchers concluded that chimpanzees probably don’t reason about belief (Call and Tomasello 2008). ¹ Ten years later, those same researchers were part of a team that reversed course: “our results, in concert with existing data, suggest 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” (Krupenye et al. 2016). ²