Brains synchronize when we hold hands or empathize with our loved one while they are in pain, and it's this that has a pain-relieving effect, say researchers from the University of Colorado at Boulder—and the more our brains sync, the greater the pain relief.
It's a phenomenon called 'interpersonal synchronization', and it happens when people mirror the state of the person they're with, encompassing patterns of breathing, heart rate and brain waves.
Lead researcher Pavel Goldstein wanted to test the idea when he noticed that his wife's pain decreased after he held her hand during child birth. He recruited 22 couples who had been together for at least a year, and put them through several scenarios while they were wearing EEG (electro-encephalography) caps, from sitting but not touching, or holding hands, or being in separate rooms.
Even being in each other's company was enough to start the couples' brains syncing, and this increased when they held hands. But when one of the partners was in pain, and there was no hand-holding, the brain syncing reduced, as did heart rate and breathing patterns.
"It appears that pain totally interrupts this interpersonal synchronization between couples and touch brings it back," said Prof Goldstein.
Empathy when the partner was feeling pain also improved brain syncing, and the more empathetic the person was, the less pain the other felt.
The researchers admit they really don't understand how this is happening, or whether similar results would be seen with people who are not a couple.