Crossing Your Fingers May Reduce How Much Pain You Feel

Did you know that crossing your fingers may reduce the pain you feel? How you feel pain is largely affected by where sources of pain are in relation to each other. This means that crossing your fingers can change what you feel on a single finger.

This latest study actually used a variation on an established pain experiment, known as the "thermal grill illusion." In the thermal grill illusion, a pattern of warm-cold-warm temperatures applied to the index, middle and ring finger respectively causes a sometimes painful sensation of burning heat on the middle finger, even though this finger is presented with cold instead of heat.

"The thermal grill is a useful component in our scientific understanding of pain," said Angela Marotta, co-lead author of the new research, in a news release. "It uses precisely-controlled stimulus to activate the brain's pain systems. This can certainly feel painful, but doesn't actually involve any tissue damage."

The thermal grill produces burning heat sensations due to a three-way interaction between the nerve pathways that tell the brain about warmth, cold and pain. The warm temperature on the ring and index fingers blocks the brain activity that would normally be driven by the cold temperature on the middle finger.

Most interesting, though, is that the interaction is based on the spatial arrangement of the fingers. In this latest study, the scientists showed that when the middle finger was crossed over the index finger, the sensation of burning heat on the middle finger was reduced. If the index finger was cooled and the middle ring fingers were warmed, though, the burning sensation increased when the middle finger was crossed over the index finger.

"Interactions like these may contribute to the astonishing variability of pain," said Patrick Haggard, senior author of the new study, in a news release. "Many people suffer from chronic pain, and the level of pain experienced can be higher than would be expected from actual tissue damage. Our research is basic laboratory science, but it raises the interesting possibility that pain levels would be manipulated by applying additional stimuli, and by moving one part of the body relative to others. Changing the spatial pattern of interacting inputs could have an effect on the brain pathways that underlie pain perception."

The findings are published in the journal Current Biology.

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