Keep Calm and Cuddle on: Social Touch as a Stress Buffer

Recent evidence from neurophysiology and human functional neuroimaging has given rise to the hypothesis that social, affective touch belongs to a distinct category of tactile experience. Such hedonic and rewarding touch is proposed to operate mainly in the domain of social interactions and relationships. Social touch may play a functional role in the physiological regulation of the body's responses to acute stressors and other short-term challenges. In this perspective, touch can buffer disadvantageous physiological effects of potentially inefficient or maladaptive responses. This review outlines the evidence for such a role, as well as the neural pathways that may support it. Direct evidence for touch as a physiological regulator is strongest for systems that underlie the maintenance of physical proximity to conspecifics in a variety of circumstances. For example, mammalian social physical contact involves social thermoregulatory processes like huddling and snuggling, which also rely on tactile thermosensory and somatosensory pathways. There is also good evidence that touch systems contribute to preventing social separation and facilitating the re-instatement of contact following social separation. Finally, prosocial touch, such as allogrooming and consolation, may utilize some of the same neural pathways as other, non-socialmeans of stress regulation. Social touch may thus serve as part of a system for regulation of responses to acute stressors, extended to include the physiological effects of social interactions.