why are we ticklish

Humans are ticklish likely as an evolutionary trait for social bonding and protection. Tickling promotes laughter and positive social interactions, which help strengthen bonds between individuals, especially among parents and children. It may also serve as a defense mechanism to protect vulnerable areas of the body by making individuals more alert to light, unexpected touches that could signal threats like parasites. This heightened sensitivity helps increase awareness and can trigger reflexive movements to protect sensitive parts. The brain's hypothalamus, which controls emotional and fight-or-flight responses, is activated during tickling, explaining the complex reactions such as laughter even though tickling is not always pleasurable. People cannot tickle themselves likely because the brain distinguishes self-generated touch from external touch, reducing the tickle response to self-touch. Different body parts, like underarms, ribs, and soles of the feet, tend to be more ticklish because they are more vulnerable physically. Tickling also plays a developmental role, helping babies train their nervous systems to recognize safe versus potentially harmful sensations.