M.C.Reddan, H.Young, J.Falkner, M.Lopez-Sola & T.D.Wager
Social Cognitive and Affective Neuroscience (2020), 1064-1075
Several types of touch (including gentle stroking, massage, and handholding) have been shown to reduce pain. Similarly, social support can reduce pain, which may in part be due to support provided through touch. Pain relief through hand holding is most effective when the support is provided by a romantic partner. There are numerous physiological and biochemical mechanisms by which touch can reduce pain, including multiple effects on pain fibers. Touch and social support also affect pain through psychological mechanisms.
The first part of this study investigated how social support including touch affects the experience of pain. Following identification of individual differences in the reduction of pain with hand holding, functional imaging was used to map these differences to pain pathways in the brain in the second part of this study.
Who was it?
In the first study, there were 51 romantic couples in a relationship lasting 6 months or longer. The average age was approximately 27 years. In the second study, there were 30 romantic couples in a relationship lasting 3 months or longer. The average age was approximately 25.5 years.
What was done?
In the first study, the main participant (either male or female) experienced the pain stimulus under two conditions: by themselves and with their partner. When the partner was present, “treatment” included gentle stroking, hand holding, or no physical touch. The pain stimulus was heat applied to the skin of the arms or legs. Skin conductance responses (SCR’s) were measured following the pain stimulus. In the second study, the female participant experienced the pain stimulus either while holding an inert rubber device, or their partner’s hand. Participants rated their pain on a visual analogue scale and functional brain MRI’s (fMRI’s) were done on the main participant.
In the first study, both men and women showed a decrease in SCR’s when they were provided social support including touch. However, only women reported a subjective reduction in pain, perhaps because of a gender bias in self-reporting and self-expression. Hand Holding had the biggest effect on reducing pain and SCR’s, although there was considerable individual variation. In the second study, the individual variation in the pain response to handholding was found to be related to activity in brain regions involved in sensation.
Touch is an important mediator of pain. Touch appears to be especially analgesic when provided in the context of social support, especially by a close partner. Clearly, there is overlap between social, physiological, and psychological systems, with implications for our understanding of pain biology.