Neuroscientists unravel the mystery of why you can’t tickle yourself

…The leading theory holds that tickling provokes laughter thanks to a prediction error by the brain. An unpredictable touch confuses it, sending it into a mini frenzy. Self-touch is always predictable … so, no frenzy.

But Brecht thinks it’s not really about prediction. Instead, he suggests that as a person touches themselves, the brain sends out a body-wide message that inhibits touch sensitivity. “We think what is happening is the brain has a trick to know: As soon as you touch yourself, don’t listen,” he says. If it didn’t, he argues, we’d all be constantly tickling ourselves every time we scratched an armpit or touched our toes.

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