Understanding social interactions and what others are thinking is essential for relationships. Monkeys, like humans, can recognize and interpret social interactions. Primates use behaviors like playing, grooming, and fighting to determine social rank and gain allies in their group. But how the brain processes social interactions is unknown.
Drs. Julia Sliwa and Winrich A. Freiwald at Rockefeller University investigated the neural circuitry underling how social interactions are interpreted. They examined the brains of rhesus macaque monkeys using whole-brain functional magnetic resonance imaging (fMRI). The study was funded in part by NIH’s National Institute of Mental Health (NIMH) and National Eye Institute (NEI). Results were published in Science on May 19, 2017.
Monkeys were placed in an fMRI scanner while being shown one of eleven different videos. The videos were designed to help researchers distinguish which brain areas respond to social and non-social cues. The footage of social cues showed monkeys interacting with each other. Footage of non-social cues showed physical objects, such as monkey toys. One set of videos showed the monkeys and/or objects in a state of inactivity. Another showed objects interacting physically with one another, such as colliding into one another. Yet another set showed monkeys playing with toys or monkeys playing or grooming other monkeys.