Friend or foe? Brain systems involved in the perception of dynamic signals of menacing and friendly social approaches

Abstract

During every social approach, humans must assess each other's intentions. Facial expressions provide cues to assist in these assessments via associations with emotion, the likelihood of affiliation, and personality. In this functional magnetic resonance imaging (fMRI) study, participants viewed animated male characters approaching them in a hallway and making either a happy or an angry facial expression. An expected increase in amygdala and superior temporal sulcus activation to the expression of anger was found. Notably, two other social brain regions also had an increased hemodynamic response to anger relative to happiness, including the lateral fusiform gyrus and a region centered in the middle temporal gyrus. Other brain regions showed little differentiation or an increased level of activity to the happy stimuli. These findings provide insight into the brain mechanisms involved in reading the intentions of other human beings in an overtly social context. In particular, they demonstrate brain regions sensitive to social signals of dominance and affiliation.

Acknowledgements

We would like to thank Gregory McCarthy and James Morris for suggestions with study design, Ronald Viola for assistance with stimuli development, Susan Perlman for FACS coding our stimuli, and Jordan Tozer and Brianna Atkins for assistance with participants. Elizabeth Carter was supported by a predoctoral fellowship from Autism Speaks. Kevin Pelphrey was supported by an NIMH Career Development Award (K01 MH071284) and by the John Merck Scholars Fund. This research was supported by NIH grant MH05286.