Spontaneous Encoding of Event Roles in Hominids

Area of Science:

• Cognitive Psychology
• Primatology
• Evolutionary Neuroscience

Background:

• Humans naturally process social interactions by identifying agents, patients, and causal relationships.
• The switch cost paradigm, a reaction time experiment, is a key tool for observing cognitive processing.
• Understanding the evolution of social cognition requires examining shared mechanisms across species.

Purpose of the Study:

• To adapt the switch cost paradigm for non-human primates.
• To investigate whether non-linguistic animals spontaneously encode event roles (agent, patient) similarly to humans.
• To explore the evolutionary origins of social event encoding in hominid cognition.

Main Methods:

• Adaptation of the switch cost paradigm for use with human and chimpanzee participants.
• Participants were tasked with identifying actors based on color cues during social interactions.
• Reaction times were measured when switching the targeted color mask between agent and patient roles.

Main Results:

• Both human and chimpanzee participants exhibited significantly increased processing times when the targeted color mask switched between agent and patient roles.
• This suggests spontaneous encoding of event roles interfered with the color search task.
• The findings were consistent across multiple human participants and one chimpanzee.

Conclusions:

• The propensity to encode social events in terms of agents and patients is a shared feature of hominid cognition.
• This suggests an evolutionarily ancient and phylogenetically shared cognitive mechanism.
• This mechanism may be foundational for language processing and understanding social dynamics.