Psychophysiological and Visual Behavioral Responses to Faces Associated with Affective and Non-affective Touch in Four-month-old Infants.

Affective touch (gentle, caress-like touch) carries a rewarding meaning, which may represent a neurophysiological foundation for the development of social interactions from the earliest stages of life. Developmental studies have shown evidence of infants' sensitivity to affective touch as reflected by a decrease in heart rate and activation of the insular cortex. Moreover, affective touch has been shown to regulate infants' emotional state, reinforce eye contact and facilitate learning of facial information, suggesting that affective touch may promote social functioning from the earliest stages of development. The present study aims to investigate the role of affective touch in enhancing engagement with social stimuli, exploring sustained attention and cardiac responses to faces as signatures of the underlying psychophysiological mechanism. Four-months-old infants (N = 40) were repeatedly presented with a female face paired with touch (hand stroking vs tapping with a brush in two different blocks) alternating with a face presented without tactile stimulation (familiarization phase), followed by a visual preference test between the two faces. Our results revealed an attenuated cardiac response in the affective compared to the non-affective condition during the familiarization phase. During the test phase infants looked longer at both the faces presented in the affective touch condition, compared to the faces in the non-affective condition. These findings suggest that affective touch might promote engagement in social interactions by facilitating physiological state regulation during processing of multisensory social information.