The Processing of Others' Touch Early in Human Development

Among the other senses touch is the first to develop and it represents the primary means through which infants learn about their surrounding world from very early in life. Evidence in human adults indicates that touch is crucial not only for own corporeal sensations, but also for understanding others’ tactile sensations likely through mirroring mechanisms. In recent years, there has been a growing interest on how infants process tactile stimulations on their own body but, to date, no study has explored how they process others’ touching gestures. In this talk, I will first present results from experiments exploring how newborns visually process others’ gestures that involve a tactile event. To explore this ability, we measured looking times and orienting responses in a visual preference task in which 2-day-old newborns were simultaneously presented with two videos depicting a gesture not involving a touch (no-touching gesture) and a gesture involving a contact (touching gesture) between human body parts (face, hand) and/or an object (spoon). Results have shown that only in the case of a human body-to-body contact, newborns could differentiate between a touching and a no-touching gesture. Crucially, newborns’ early sensitivity to touch vanished when they were presented with gestures that involved an object as the agent of the touch. Another interesting issue refers to the development of mirroring mechanisms for touch. Recent lines of evidence in human adults have shown that viewing touch may vicariously activate a putative tactile mirror system, comprising the somatosensory cortices (SI and SII). I will present evidence of the origins of such ‘tactile mirror system’, showing the vicarious activation of the somatosensory cortex during touch observation, as indexed by somatosensory evoked potentials (SEPs), in 8-month-old infants.