When we tickle ourselves, however, a completely different part of the brain activates: the cerebellum. This area controls and, most importantly, predicts muscle activity. Since humans are self-aware, their cerebellums warn the rest of their brains of the self-tickling and silence the alarm bells. No laughter, no fun. Interestingly, people with schizophrenia often can tickle themselves, likely because unusual variations in their brains keep them from logically connecting their own movements to the resulting tickling sensation.
Scientists hypothesize that laughter has several other evolutionary purposes. The ability to laugh can be a sign of social intelligence. Gargalesis is only experienced by humans and primates, so we likely inherited this tendency as a way to strengthen social bonds. It may also be an important method of communication between parents and their babies before the infants are able to talk. That means tickling isn't just a hilarious sensation; it's also a sign of your humanity. To learn more about the science behind tickling, watch the videos below.