Wired to Be Social: The Ontogeny of Human Interaction

Umberto Castiello,Vittorio Gallese,Maria Bulgheroni,Giuseppina D'Ottavio,Luisa Sartori,Cristian Nelini,Cristina Becchio,Laura Blason,Stefania Zoia,Aldo Rustichini

doi:10.1371/journal.pone.0013199

Abstract

BackgroundNewborns come into the world wired to socially interact. Is a propensity to socially oriented action already present before birth? Twin pregnancies provide a unique opportunity to investigate the social pre-wiring hypothesis. Although various types of inter-twins contact have been demonstrated starting from the 11th week of gestation, no study has so far investigated the critical question whether intra-pair contact is the result of motor planning rather then the accidental outcome of spatial proximity.Methodology/Principal FindingsKinematic profiles of movements in five pairs of twin foetuses were studied by using four-dimensional ultrasonography during two separate recording sessions carried out at the 14th and 18th week of gestation. We demonstrate that by the 14th week of gestation twin foetuses do not only display movements directed towards the uterine wall and self-directed movements, but also movements specifically aimed at the co-twin, the proportion of which increases between the 14th and 18th gestational week. Kinematic analysis revealed that movement duration was longer and deceleration time was prolonged for other-directed movements compared to movements directed towards the uterine wall. Similar kinematic profiles were observed for movements directed towards the co-twin and self-directed movements aimed at the eye-region, i.e. the most delicate region of the body.Conclusions/SignificanceWe conclude that performance of movements towards the co-twin is not accidental: already starting from the 14th week of gestation twin foetuses execute movements specifically aimed at the co-twin.

Highlights

One-to-one interactions are the cradle of social cognition
Twin pregnancies constitute an experiment of nature which offers the unique opportunity to explore social behaviour before birth
By investigating kinematic profiles of movements in five pairs of twin foetuses, we demonstrated that, by the 14th week of gestation, twin foetuses display movements directed towards the uterine wall and self-directed movements, and movements aimed at the co-twin

Summary

Introduction

One-to-one interactions are the cradle of social cognition. Infants do not develop social understanding by merely watching other people at a distance. The results showed that the spatial and temporal characteristics of foetal movements were by no means uncoordinated, but depended on the goal of the different motor acts, suggesting a surprisingly advanced level of motor planning Along these lines it might be advanced that, if foetuses plan movements towards the co-twin, a specific kinematic pattern related to the social end goal of the movement might be expected. If inter-twin contact reflects motor planning, differences in kinematics might be expected between movements directed towards the co-twin and movements directed towards one’s own body or the uterine wall. We tested this hypothesis by investigating the kinematics of movement in five pairs of twin foetuses. Because the presence of a co-twin may facilitate or prime an anticipated propensity to act, signs of kinematic differentiation between hand to mouth and hand to eye movements might be expected to appear earlier in twin foetuses

Methods

Results

Discussion