I’ve always wondered why we are ticklish in some spots and why we laugh. So here is an explanation. Under our skin there are many nerve endings that alert the brain of exposure to things like cold and hot. When the nerve endings are stimulated by a person’s fingers or a feather, they send a signal to your brain. The touch that results in a tickling sensation is because of two regions of the brain.

The somatosensory cortex analyzes touch. The signal sent from the sensory receptors pass through the anterior cingulated cortex, which hosts pleasant feelings. These create the tickle sensation. This is a known fact because an MRI was used in studies to prove this. The MRI also showed that we can’t tickle ourselves. The cerebellum, responsible for movement, can sense when a self-tickle is coming and tell the brain. The brain filters out unnecessary information so that it can put its focus on important stuff. A touch from yourself is not worth your mind’s attention, so your brain throws out the information before it gets to your consciousness.

Charles Darwin and Ewald Hecker said that humor and tickling are related because both require a good mood to work. However, the truth is that humor and tickling aren’t related. Neuroscientists have explained that “we’re showing our submission to an aggressor when we are being tickled.” The areas of the body that are most ticklish are also most prone to injury. Through tickling, one person is teaching the other to defend them self.

Darwin suggested that we are ticklish in places where we aren’t usually touched by others. The bottom of the feet and underarms are the most common ticklish places. The soles of the feet diffuse pressure when we’re standing or walking so it isn’t commonly touched. The soles of the feet have a lot of Meissner’s corpuscles, which are sensitive nerve receptors close to the skin’s surface. “Your underarm has the axillary vein and artery, and allows access to your heart, since the rib cage no longer provides protection to the chest cavity at the underarm” (Clark). The neck is also another common ticklish spot because there are no bones.

Why do we laugh when we are being tickled?

The laughter that comes from being tickled is a defense mechanism to signal submissiveness. It’s an acknowledgement of defeat. Tickling and laughing activate the Rolandic Operculum that controls facial movements and emotional reactions. However, tickling laughter and funny laughter were found to be different. Tickling laughter stimulates the hypothalamus that controls temperature, hunger, tiredness and sexual behavior. It controls instinctive reactions to situations like flight or fight. This is why some people laugh before they are even tickled. ‘When you tickle someone, you actually stimulate the unmyelinated nerve fibers that cause pain,’ said Dr. Alan Hirsch.