Impact of social context on human facial and gestural emotion expressions

Humans flexibly adapt expressions of emotional messages when interacting with others. However, detailed information on how specific parts of the face and hands move in socio-emotional contexts is missing. We identified individual gesture and facial movements (through automated face tracking) of N = 80 participants in the UK, produced while watching amusing, fearful, or neutral movie scenes either alone or with a social partner. Amusing and fearful scenes, more so than neutral scenes, led to an overall increase in facial and gesture movements, confirming emotional responding. Furthermore, social context facilitated movements in the lower instead of upper facial areas, as well as gesture use. These findings highlight emotional signaling components that likely underwent selection for communication, a result we discuss in comparison with the nonhuman primate literature. To facilitate ecologically valid and cross-cultural comparisons on human emotion communication, we additionally offer a new stimuli database of the recorded naturalistic facial expressions.