Visual perception grounding of social cognition in preverbal infants

Social life is inherently relational, entailing the ability to recognize and monitor not only the social entities in the visual world, but also the relations between those entities. In the first months of life, visual perception already shows to privilege -i.e., to process with the highest priority and efficiency- socially relevant entities such as faces and bodies. Here, we show that within the sixth month of life, infants also discriminate between different configurations of multiple human bodies, based on the internal visuo-spatial relations between bodies, cuing, or not, interaction. We measured the differential looking times between two images of the same body dyad, differing only for the relative spatial positioning of the two bodies. Results showed that infants discriminated between face-to-face and back-to-back body dyads (Experiment 1), and treated face-to-face dyads (but not back-to-back dyads) with the same efficiency (i.e., processing speed) of single bodies (Experiment 2). Looking times for dyads with one body facing another without reciprocation, were comparable to looking times for face-to-face dyads, and differed from looking times to back-to-back dyads, suggesting a general discrimination between presence versus absence of relation (Experiment 3). Infants' discrimination of images based on relative positioning of items was selective to body dyads, and did not generalize to body-object pairs (Experiment 4). We suggest that the infants' early sensitivity to the relative positioning of bodies in a scene is a building block of social cognition, preparing the discovery of the keel and backbone of social life: relations.