Proceedings of the Annual Meeting of the Cognitive Science Society

Languages tend to describe who is doing what to whom by placing subjects before objects. This bias for agents is reflected in event cognition: agents capture more attention than patients in human adults and infants. We investigated whether this agent preference is unique to humans. We presented Guinea baboons (Papio papio, N = 13) with a change detection paradigm with chasing animations. The baboons had to respond to a colour change which was applied to either the chaser/agent or the chasee/patient. They were faster to detect a change to the chaser than to the chasee, which cannot be explained by low-level features in our stimuli. Our study suggests that baboons show an agent preference similar to human infants and adults. This may be an evolutionarily old mechanism that is shared between humans and other primates, which could have become externalised in language as a tendency to place the subject first.