While some people are not ticklish at all, some others will literally laugh until they cry when getting tickled. There is a lot we still don’t know about this physical and neurological process, but scientists have been studying tickling since the days of Aristotle. Even back in 350 BC, the Greek philosopher tried to understand why one cannot tickle oneself. Here’s what we do know about this phenomenon.
What Does Tickling Do To Our Brain?

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Before we try to understand why some people are ticklish, we need to understand what tickling does to our brains. When someone touches us unexpectedly, nerve endings in our skin send messages to the cerebellum, the area of the brain that monitors movement and reacts to sensations.
Why Are We Ticklish?

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There are two theories when it comes to explaining why people feel ticklish. The first school of thought hypothesizes that being ticklish evolved as a defense mechanism to protect vulnerable areas. That is, feeling ticklish draws attention to external stimuli and alerts us to predators, such as bugs crawling on our skin. On the other hand, Charles Darwin theorized in the late 19th century that tickling is a mechanism of encouraging social bonding.
Why Do We Laugh When We’re Tickled?

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If our bodies feel ticklish as a defense mechanism, why does it make us laugh uncontrollably? The truth is no one knows for sure. Some evolutionary researchers studied MRI scans of people being tickled and believe that our laughter is controlled by the hypothalamus. This small region of the brain is responsible for fight or flight responses and comes into play when we’re being tickled. According to this theory, laughing would signal our submission to the person tickling us in an attempt to prevent them from continuing. Other scientists believe that laughing is a response that we learn as kids. When young children are being tickled in a playful situation when they are already laughing, they might associate tickling with laughter.