The study suggests crossing arms at the wrists mixes up the brain's perception of pain signals sent from the hands to the brain and reduces the intensity of pain.
Researchers say the findings may lead to new therapies to treat painful conditions by manipulating the brain's perception of the body.
"Perhaps when we get hurt, we should not only "rub it better" but also cross our arms," says researcher Giandomenico Iannetti, MD, of University College London, in a news release.
Conflicting Information From the Brain
In the study, published in Pain, researchers used a laser to deliver a pin-prick-like pain sensation to the hands of eight adult volunteers in two different positions. The first time, the participants had their hands at their sides and the second time they crossed their arms over the center of their bodies.
The participants then rated their perception of pain. Researchers also measured the brain's electrical response using an electroencephalography (EEG).
The results showed that both the perception of pain and EEG activity was reduced when the arms were crossed.
Researchers say the reduction in pain is most likely due to confusion in the brain from conflicting information being sent from the brain's internal and external maps.
"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," says Iannetti. "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."