Visual preference for socially relevant spatial relations in humans and monkeys

Abstract

As an extremely relevant social signal, a body/face/gaze facing towards oneself holds an individual’s attention. We asked whether, going beyond an egocentric stance, facingness between others has a similar effect, and why. Using a preferential-looking time paradigm, we showed that human adults looked preferentially at two bodies facing each other, relative to the same bodies presented back-to-back. Moreover, facing dyads were rated higher in social semantic dimensions, showing that facingness adds social value to stimuli. The preference for facing dyads thus reflects the ability to understand the social content of facingness beyond first-person interactions. In showing the same preference in macaques and in young children, anticipated by particularly efficient processing of facing dyads in early infancy, we propose that this ability is part of the fabric of a social mind.

Innate sensitivity to face-to-face biological motion

“… 18 The same looking-time paradigm was adopted in adult humans and macaques, confirming the different attention driven by the two types of stimuli, and thus, the relevance of such configurations. 20 Those results are compatible with the evidence of perceptual adaptation for efficient processing of seemingly interacting (e.g., face-to-face) bodies. In fact, it has been shown that, in conditions of visual noise, facing bodies are more likely to be detected and recognized than the same two bodies facing away from each other.…”

“…This finding provides evidence that the recognition of face-to-face configuration, likely indicative of interaction, which has been found in infants, adult humans, and adult macaque monkeys, is observed also in birds and does not derive from experience but it is likely to be biologically predisposed in the vertebrate brain. Moreover, given that previous studies in infants never reported a preference for face-to-face stimuli, but only a capacity for discrimination, 18 , 20 the present study is the first report of such an early preference.…”

“…In humans, visual sensitivity to the difference between face-to-face and back-to-back bodies appears early in development 18 and evolves into a preference for face-to-face bodies, which is shared with monkeys. 20 In those studies, the looking times of six-month-old infants were computed while presenting simultaneously two dyads showing face-to-face and back-to-back bodies, respectively, finding a significant difference in looking times toward the two types of dyads. 18 The same looking-time paradigm was adopted in adult humans and macaques, confirming the different attention driven by the two types of stimuli, and thus, the relevance of such configurations.…”