Year: 2026
Type: preprint
Abstract: Humans adeptly navigate complex social environments by attempting to anticipate the actions and emotional responses of others. Although our closest ape relatives have sophisticated social cognitive abilities, we do not know whether they have a cognitive understanding of others’ emotions. For the epistemic emotion surprise, a cognitive understanding would require sensitivity to an agent’s belief, to reality, and to any misalignment between the two – allowing one to model the mental conditions that drive surprise. In a non-invasive eye tracking study with 31 chimpanzees and bonobos, apes showed evidence of a cognitive understanding of surprise: they detected the misalignment between an agent’s belief and reality, exhibiting greater pupil dilation right before an agent encountered an unexpected outcome relative to an expected one. This suggests that apes and humans share a more complex understanding of others’ mental lives than previously thought, capacities that likely evolved millions of years ago in a common ancestor.
Institutions: University of California, Los Angeles, Max Planck Institute of Animal Behavior, University of California, Santa Barbara, Max Planck Institute for Evolutionary Anthropology, Duke University, University of Regensburg, German Primate Center, Leibniz ScienceCampus Primate Cognition, University of Göttingen, Johns Hopkins University, Santa Fe Institute, Indiana University
Language: English
Topic: Primate Behavior and Ecology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7221635793