Great apes distinguish true from false beliefs in an interactive helping task.

David Buttelmann,Malinda Carpenter,Michael Tomasello,Frances Buttelmann,Josep Call,Juliane Kaminski

doi:10.1371/journal.pone.0173793

Abstract

Understanding the behavior of others in a wide variety of circumstances requires an understanding of their psychological states. Humans’ nearest primate relatives, the great apes, understand many psychological states of others, for example, perceptions, goals, and desires. However, so far there is little evidence that they possess the key marker of advanced human social cognition: an understanding of false beliefs. Here we demonstrate that in a nonverbal (implicit) false-belief test which is passed by human 1-year-old infants, great apes as a group, including chimpanzees (Pan troglodytes), bonobos (Pan paniscus), and orangutans (Pongo abelii), distinguish between true and false beliefs in their helping behavior. Great apes thus may possess at least some basic understanding that an agent’s actions are based on her beliefs about reality. Hence, such understanding might not be the exclusive province of the human species.

Highlights

Humans’ closest primate relatives, great apes, understand much about the psychological functioning of others. They can identify the goals of others, as evidenced by their ability to distinguish between intentional and accidental actions and to identify what others want in order to help them [1, 2]
For many years it was thought that great apes lacked this understanding: In a series of previous experimental studies, chimpanzees, bonobos, and orangutans showed no reliable evidence of passing false-belief tests [6,7,8,9]
A total of 34 great apes participated in this study: twenty-three chimpanzees, five bonobos, and six orangutans

Summary

Introduction

Humans’ closest primate relatives, great apes, understand much about the psychological functioning of others. In the false-belief condition the experimenter left the room and infants watched as a research assistant moved the toy to a different box.

Results

Conclusion