Social touch in mother–infant interaction affects infants’ subsequent social engagement and object exploration

Infants’ social touch with caregivers has been considered a means of regulating infant physiological and emotional state. In non-human mammals, such regulatory function also facilitates infant exploration and social behavior. However, the types of social touch in human mother–infant interaction that contribute to specific behavioral responses toward people and objects remain unclear. Using a pre- and post-task design, this study investigated the effects of social touch during mother–infant interactions on infants’ subsequent preferential looking at social stimuli, social engagement with strangers, and object exploration. Between tasks, mothers and infants spent the time playing in one of two conditions, More Physical Contact or Less Physical Contact. We found that infants in the More Physical Contact Condition showed a greater decrease in evasive behavior with the stranger and enhanced object exploration than those in the Less Physical Contact Condition. Conversely, social touch did not affect infants’ preferential looking at static social images. Among the types of social touch, the frequency of affectionate touch reduced evasive behavior to the stranger and facilitated object exploration. These results suggest that social touch, especially affectionate touch, during mother–infant interactions, assist in the modulation of infants’ evasive behaviors toward people and object exploration.