Great apes use self-experience to anticipate an agent’s action in a false-belief test

Abstract

Human social life depends on theory of mind, the ability to attribute mental states to oneself and others. A signature of theory of mind, false belief understanding, requires representing others’ views of the world, even when they conflict with one’s own. After decades of research, it remains controversial whether any nonhuman species possess a theory of mind. One challenge to positive evidence of animal theory of mind, the behavior-rule account, holds that animals solve such tasks by responding to others’ behavioral cues rather than their mental states. We distinguish these hypotheses by implementing a version of the “goggles” test, which asks whether, in the absence of any additional behavioral cues, animals can use their own self-experience of a novel barrier being translucent or opaque to determine whether another agent can see through the same barrier. We incorporated this paradigm into an established anticipatory-looking false-belief test for great apes. In a between-subjects design, apes experienced a novel barrier as either translucent or opaque, although both looked identical from afar. While being eye tracked, all apes then watched a video in which an actor saw an object hidden under 1 of 2 identical boxes. The actor then scuttled behind the novel barrier, at which point the object was relocated and then removed. Only apes who experienced the barrier as opaque visually anticipated that the actor would mistakenly search for the object in its previous location. Great apes, therefore, appeared to attribute differential visual access based specifically on their own past perceptual experience to anticipate an agent’s actions in a false-belief test.

Nonadjacent dependency processing in monkeys, apes, and humans

“…A gold standard for the comparative approach hence involves collecting comparable datasets through the cross-species application of matching experimental paradigms. This strategy has been extremely productive when examining other traits thought to be key to human cognition such as cumulative culture ( 19 ), hyper-cooperation ( 20 ), working memory ( 21 ), and theory of mind ( 22 , 23 ). Here, we undertook such a directly comparative investigation of the evolutionary roots of Non-AD processing by implementing a standardized, auditory artificial grammar learning paradigm in common marmosets ( Callithrix jacchus ), chimpanzees ( Pan troglodytes ), and humans.…”

Toddlers' social evaluations of agents who act on false beliefs

“…These results suggest that infants expected the actor to look for the object in its original location, where she had last seen it. Other behavioral research has found evidence of implicit false-belief understanding in young children (24,28), older infants (26,27), and non-human primates (29,30). Moreover, neuroimaging research has found evidence that infants as young as 6 to 7 months of age represent others' false beliefs when watching videos of others' actions (31,32).…”

Crossing the Rubicon: Behaviorism, Language, and Evolutionary Continuity

“…It is possible, though, that the apes had simply learned that people tend to look for things where they last saw them, and were not considering what the person believed. Kano et al (2019) offer a more exacting test in which the apes saw a video in which an actor saw an object hidden under one of two boxes. The actor then moved behind a barrier that was either translucent or opaque, and the object was shifted to the other box.…”