What Is the Evolutionary Purpose of Tickling?

You probably know that you can’t tickle yourself. And although you might be able to tickle a total stranger, your brain also strongly discourages you from doing something so socially awkward.

These facts offer insight into tickling’s evolutionary purpose, says Robert R. Provine, a neuroscientist at the University of Maryland and the author of the book Laughter: A Scientific Investigation. Tickling, he says, is partly a mechanism for social bonding between close companions and helps forge relationships between family members and friends.