When you hit your leg on a desk, you rub it right away. Does this really help? Yes, it does. In 1965, two scientists said that touch signals can partly close a "gate" for pain in the spinal cord, the bundle of nerves in your back.

Later experiments showed that touching near the painful spot makes pain weaker. Slow, gentle stroking works especially well. So when a child falls, rub the spot softly!

When we bump into something, we often rub the painful spot without thinking. In 1965, two scientists proposed the gate control theory of pain. According to this idea, pain signals pass through a kind of gate in the spinal cord on their way to the brain. Signals from touch nerves can partly close this gate, so less pain gets through.

Later experiments supported the idea that touch reduces pain. In a 2014 study, touching the skin made laser heat pain feel weaker, and the effect was stronger when the touch was closer to the painful spot. A 2017 Swedish study of 44 people found that slow brushing reduced pain, while fast brushing and vibration did not.

Bang your shin on a table and your hand goes straight to the spot. Research suggests the reflex does some good. In 1965, Melzack and Wall proposed the gate control theory. Pain signals, they argued, pass through a "gate" in the spinal cord, and input from large touch-sensitive nerve fibers activates inhibitory neurons that partly close it. The theory changed how scientists thought about pain.

Instead of a message delivered unchanged, pain became something that could be modulated along its route. A 2013 review noted that the theory's detailed spinal circuitry has needed revision, but the basic idea has stayed influential in pain research. In 2014, researchers at University College London delivered brief laser heat pain while touching the skin.

Volunteers rated the pain as weaker and were worse at judging its intensity, and touch closer to the painful site worked better. A 2017 Swedish study of 44 healthy adults found that slow brushing reduced heat pain, while fast brushing and vibration did not. The authors linked this to special nerves that respond to gentle stroking, although those nerves were not recorded directly. Reassurance and distraction probably help as well.