Whether you find it deliciously delightful or a form of torture, there’s no arguing the fact that our feet are extremely ticklish. But why exactly are the soles of our feet so sensitive to tickling? As it turns out, thousands of nerve endings are to blame for ticklish feet.
Though our feet are extremely strong (they support the entire weight of our bodies, after all), they’re also very sensitive due to almost 8,000 nerve endings located in each foot. Scientists believe that these nerve endings — called Meissner’s corpuscles — exist as a sort of evolutionary defense mechanism to help protect us from injuries, harmful impacts and potentially dangerous insects or reptiles on the ground. And because the nerves are a mixture of both touch receptors and pain receptors that carry information along neural pathways to the brain, feet tickling creates very different sensations in each individual person.
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Add to that the fact that there are actually two different types of tickling, discovered in 1897 by psychologists G. Stanley Hall and Arthur Allin. Light tickling, such as the brush of a feather across the soles of your feet, is called knismesis. This type of tickle oftentimes produces irritation that makes a person squirm or instinctively pull away rather than laugh with pleasure. Meanwhile, harder tickling is called gargalesis. This type of tickle comes from using your fingers on the sole of the foot, for example, and usually elicits laughter from your “victim” if done in a playful manner.
While some people genuinely dislike the fact that their feet are ticklish, having sensitive feet is actually a good thing. Non-ticklish feet could be a sign of problems with a person’s nerve receptors, which can happen from illnesses like arthritis, diabetes and neuropathy, which is a degenerative nerve disease.
Darwin’s Theory On Ticklish Feet
While many scientists believe ticklishness is a reflex, some — like Charles Darwin — theorize that it’s actually a social-bonding behavior instilled at an early age by parents. Darwin posited that laughter results from the anticipation of being tickled: Children who expect to be tickled will most likely laugh, while a child who does not expect to be tickled will most likely pull away or show displeasure. Similarly, tickling the feet of an unsuspecting stranger would likely produce very different results than tickling the feet of a loved one.
So the lesson to take away from all of this: Whether you’re the tickler or the ticklee, foot tickling is a very touchy subject.