Crossing Arms Reduces Pain Intensity By Confusing The Brain

If you have a pain, for example in your hand, and you cross your arms over the midline, it reduces the intensity of that sensation of pain by confusing the brain, scientists from University College London reported in the journal Pain. The researchers think that conflicting information between the brain's two maps - one for the person's body and the other for external space - results in a reduction of pain sensation.

When you do things, your brain is used to your left hand being on the left side of your body and your right hand on your right. When we cross our arms, the hands are on the other side - there is a mismatch - resulting in weaker processing of noxious information, and a lower sensation of pain.

Dr Giandomenico Iannetti, lead author, suggested:

"Perhaps when we get hurt, we should not only
"rub it better" but also cross our arms."

In this small study involving eight participants, a laser generated a four millisecond pin prick on their hands which gave them a sensation of "pure pain" - pain with no touch.

The participants experienced this stimulus with their arms at their sides, and then their arms crossed. They were asked to rate their perception of pain intensity. An EEG (electroencephalography) was also used to measure their electrical brain responses.

Both the participants' self reporting and the EEG readings showed that their sensation of pain was considerably weaker with crossed arms.

Iannetti wrote:

"In everyday life you mostly use your left hand to touch things on the left side of the world, and your right hand for the right side of the world - for example when picking up a glass of water on your right side you generally use your right hand.

This means that the areas of the brain that contain the map of the right body and the map of right external space are usually activated together, leading to highly effective processing of sensory stimuli. When you cross your arms these maps are not activated together anymore, leading to less effective brain processing of sensory stimuli, including pain, being perceived as weaker.

These findings could help create new ways for treating pain, the researchers believe.