Social goals shape the facial expression of emotion [electronic resource] : subjective, behavioral, and neural bases of communicating feelings
Keywords: Psychology.

Audiences shape the facial expression of emotion, but the source of this effect remains contested. Traditional emotion theory holds that facial expressions constitute 'read-outs' of underlying experience. Alternatively, social communicative perspectives claim that facial expressions reflect goals for communication with audiences. These two potential sources could correspond to activity within two brain systems, respectively involved in experiencing emotion, and thinking about other individuals' minds. However, neuroimaging research focuses almost entirely on brain structures involved in perceiving emotional facial expressions, leaving unclear whether similar systems are also recruited when people generate facial displays. It is further unknown whether similar systems support the production of both genuine and disingenuous facial expressions. In Study 1, we asked social targets to view and rate emotional images, while either believing that they were visible (audience) or not visible to an observer (no audience). In all cases, observers actually viewed videos of targets and inferred targets' emotional states. Audiences did not affect self-report or physiological measures of target experience, but did increase targets' expressivity as assessed via facial electromyography (EMG). Increased expressivity, in turn, improved observers' accuracy about target experiences. These data suggest that social goals shape emotional displays in the service of interpersonal understanding. Study 2 directly manipulated social goals and examined the neural correlates of resulting audience effects. Pairs of friends took turns viewing positive and neutral images while undergoing simultaneous fMRI scanning and EMG recording of zygomaticus major, a facial muscle associated with smiling. Participants sometimes believed they were visible to their friend via video camera, and sometimes believed they were not. When participants viewed pleasant images, their EMG responses parametrically tracked activity in brain systems related to experiencing emotion. When they additionally believed that they were visible to their friend, EMG responses further tracked activity in brain structures associated with mentalizing. These findings indicate that neural systems involved in experiencing emotion and mentalizing support the production of facial expressions. Study 3 replicated and extended Study 2 to the production of disingenuous facial expressions. Participants viewed positive and neutral images under the belief that their faces were visible to an observer via video camera. Critically, participants were sometimes incentivized to convey their emotions correctly or incorrectly, and sometimes viewed images without any incentive. When we incentivized participants to communicate with observers, they exhibited increased activity in regions associated with mentalizing, relative to no incentive. This pattern emerged whether participants viewed positive or neutral images. However, viewing positive images elicited greater activity in areas related to emotional experience, as compared to neutral image-viewing. Future analyses will directly test whether brain systems involved in mentalizing support the production of both genuine and disingenuous facial expressions.