By Pat Anson, Editor
Holding hands with a loved one is a simple and effective way to relieve some of their pain, according to the results of a novel study.
The key is to take advantage of an evolutionary trait that helped humans become social beings.
“Skin to skin touch is important for pain reduction, which may explain people’s preference for social touch. Moreover, touch activates reward circuits in the brain. Indeed, skin-to-skin touch has been shown to activate the reward system, which results in pain reduction both in animals and in humans,” wrote lead author Pavel Goldstein, a pain researcher in the Cognitive and Affective Neuroscience Lab at CU Boulder.
“It seems that this phenomenon has evolutionary roots. For example, non-human primates devote much more time to grooming than they actually need for hygiene reasons, resulting in endogenous opioid release, as well as pain and stress reduction.”
The new study, published in the journal Scientific Reports, is the first to explore interpersonal synchronization in the context of pain and touch.
Scientists have long known that people subconsciously sync their footsteps with the person they're walking with or adjust their posture to mirror a friend's during conversation. Studies have also shown that when romantic couples are simply in each other's presence, their cardiorespiratory and brainwave patterns sync up.
Goldstein came up with the idea of testing how synchronization affects pain after witnessing the birth of his daughter.
"My wife was in pain, and all I could think was, 'What can I do to help her?' I reached for her hand and it seemed to help," he recalls. "I wanted to test it out in the lab: Can one really decrease pain with touch, and if so, how?"
Goldstein recruited 22 healthy heterosexual couples, age 23 to 32, and put them through a series of tests aimed at mimicking that delivery-room scenario.
Men were assigned the role of observer, while the women were subjected to mild heat pain in the forearm for two minutes. As instruments measured their heart and breathing rates, the couples were put in three different scenarios: together but not touching; together holding hands; or sitting in separate rooms.
The couples’ heart and breathing rates synced physiologically while just sitting together. But when a woman was subjected to pain and her partner couldn't touch her, that synchronization ended. When he was allowed to hold her hand, their rates fell into sync again and her pain decreased.
"It appears that pain totally interrupts this interpersonal synchronization between couples," Goldstein said. "Touch brings it back.
“It is possible that the target of pain communicates back the analgesic effect of touch to the observer. Thus, the use of touch may improve the quality of non-verbal physiological communication between partners, especially when one of them feels pain, enabling the toucher to better project his empathy to the female partner and consequently have an analgesic effect.”
Goldstein's previous research found that the more empathy a man showed for a woman, the more her pain subsided during touch. The more physiologically synchronized they were, the less pain she felt. It's not clear yet whether the decrease in pain increased the synchronicity, or vice versa.
"It could be that touch is a tool for communicating empathy, resulting in an analgesic, or pain-killing, effect," said Goldstein.
Further research is needed to figure out how a partner's touch eases pain. Goldstein suspects interpersonal synchronization may play a role, by affecting a region of the brain that is associated with pain perception, empathy, and heart and respiratory function.
The study did not explore whether the same effect would occur with same-sex couples, or what happens when the man is the subject of pain. Goldstein hopes the research will help lend scientific credence to the notion that touch can ease pain.