Abstract
The human visual system is well-tuned to detect not just the presence of other people, but also the social relationships between them. For example, recent work shows that facing dyads (or groups of two) are detected faster than non-facing dyads in visual search tasks. Everyday life however often involves social groups larger than two, and so here we examined if this perceptual advantage also occurs for groups of three or more individuals. Participants searched either for groups of facing individuals (in arrays of non-facing individuals) or groups of non-facing individuals (in arrays of facing individuals). In Experiment 1, facing groups of three (triads) were detected faster relative to non-facing triads, suggesting a perceptual advantage for interacting groups. Experiment 2 further indicated that this search advantage was not driven by perceptual grouping of dyads within triads, as it vanished when triad group unity was reduced to dyads by singling out one individual. Experiment 3 showed that search advantage for facing triads held when the triads were inverted, suggesting that perception of body orientation may be one of the principles behind social perceptual grouping. Finally, in Experiment 4 we manipulated group size from three to seven individuals and found that the magnitude of the social search advantage was modulated by this factor. Thus, human perception appears to be well tuned to extract and represent not just simple social relationships but also more complex group social structures as well.