First, we examined whether social interactions capture observers’ attention. In visual search experiments, we found that participants locate pairs of facing individuals faster in search displays than pairs of non-facing individuals. We discovered that this search advantage is attributable to the arrangement of attention cues within facing and non-facing dyads. When viewed in profile, faces and bodies cue observers’ attention leftwards or rightwards, according to their orientation. The configuration of these attention cues in facing dyads creates an attention trap whereby the lefthand actor directs observers’ attention towards the righthand actor and vice-versa. Over a series of experiments, we proved that this attention trap is responsible for the search advantage.
Second, we sought to elucidate the visual processing is engaged by static interaction stimuli. We showed that the perception of interpersonal distance is affected by the Muller-Lyer illusion. As result, the space between two facing people viewed in profile (i.e. the nose-to-nose distance) appears to be expanded. Similarly, we found that the perceptual representations of dyads formed by observers afford greater feature migration (e.g. participants mistakenly believe the face of the lefthand actor appeared with the body of the righthand actor) when the individuals are arranged face-to-face, than when arranged back-to-back.
Third, we explored the visual processing engaged by dynamic interaction stimuli. It has been proposed that pairs of individuals shown upright and face-to-face recruit configural visual processing that aids the detection and interpretation of social interactions. Back-to-back or upside-down dyadic arrangements are not thought to engage this processing. According to this account, participants should exhibit disproportionate sensitivity to changes in interpersonal distance when dyads are shown upright and face-to-face. However, across four highly powered experiments we show that participants exhibit similar sensitivity to changes in interpersonal distance regardless of whether dyads are presented upright or inverted, face-to-face or back-to-back.
Fourth, we examined how are social interactions are represented within the visual brain. The social perception network comprises a series of brain regions within the human visual system that are each thought to play a key role in the perception of faces, bodies, and actions. Across two neuroimaging experiments, we revealed that regions of the social perception network – notably EBA – represent information about observed interpersonal synchrony. A previously unknown region of right fusiform cortex also responds more strongly to synchronous than to asynchronous interaction kinematics.
Finally, we examined whether autistic participants exhibit impaired perception of social interactions. Across two studies, we found no evidence that participants with autism exhibit aberrant processing of social interactions. In one study, we found that autistic participants showed typical sensitivity to changes in interpersonal distance when viewing pairs of facing individuals from third-person perspectives. In a second study, we found that autistic participants exhibit a typical search advantage for facing dyads: like non-autistic controls, autistic participants find pairs of facing individuals faster in search displays, than pairs of non-facing individuals.
Our findings have been published in leading international journals (e.g. Journal of Experimental Psychology: General). Our work has also been presented at national (e.g. meetings of the Experimental Psychology Society) and international (e.g. the European Conference on Visual Perception) conferences.
