Why Can’t You Tickle Yourself? Your Brain Actually Prevents It From Happening

Key Takeaways About Why You Can’t Tickle Yourself

• Even if you are a very ticklish person, your brain generally won’t let you tickle yourself, because it can anticipate when and where the tickles will occur.
• There are two types of tickling: one is a light, feather-like touch, while the other is a harsher, more aggressive touch.
• Even though you laugh while being tickled, and this is meant to be a form of “play,” you also feel a hint of anticipated fear.

Whether it’s a brutal jab to the ribs or a sneak attack to the feet, being tickled often results in a burst of uncontrollable laughter followed by a frantic attempt to escape. But when you try to tickle yourself, you’ll notice that nothing actually happens.

So why can’t you tickle yourself? And what does this tell us about how the brain works?

It turns out that tickling involves a lot more than just the sense of touch. The response is a complex mix of anticipation, surprise, social play, and finely tuned sensory processing.

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The two types of tickles

Tickling is often thought of as a single sensation, but scientists tend to divide tickles into two main types. Neuroscientist Shimpei Ishiyama, who studies the neurobiology of tickling and is head of the Neurobiology of Positive Emotions research group at the Central Institute of Mental Health in Mannheim, said it is essential to understand the difference between the two types of tickling.

“The distinction is often intuitive if described as a contrast between a light, feather-like touch, [known as knismesis]and more vigorous touch on areas such as the sides of the torso [known as gargalesis]. The former usually produces an itchy sensation that motivates wiping or removal, while the latter may trigger involuntary laughter,” Ishiyama said. Discover.

In English and many other languages, “[b]Both sensations are commonly called “ticklish,” but they differ along several dimensions: the body regions involved, the mode of stimulation, and the behavioral response of the person being tickled,” Ishiyama said. Discover.

But in other languages, like Turkish, he added, speakers naturally distinguish between the two types of tickles.

“Although this distinction is not crucial in everyday conversation, it is essential in scientific research, because failing to separate the two risks confusing fundamentally different sensory and behavioral phenomena under the same label,” Ishiyama said.

Why can’t you tickle yourself?

When someone else tickles you, the sensation is unexpected and out of your control. But when you try to tickle yourself, your brain predicts precisely where you’re going to be touched and then limits the strength of the sensory signals resulting from that touch.

“The reduced sensation during contact with oneself compared to contact with others is known as sensory attenuation,” Ishiyama told Discover. “For many years, this has been interpreted as a consequence of feedforward motor signals: when a movement is generated, brain regions, including the cerebellum, produce what is called an efference copy, an internal copy of the motor command.”

This internal copy is then used to modify the sensory feedback the brain expects from its own movements, a process known as corollary discharge, according to a 2024 study in PNAS.

In experiments with rats, Ishiyama and colleagues attributed this attenuating effect to specific cellular mechanisms within the somatosensory cortex.

“Functionally, sensory attenuation during contact with the self is thought to help the brain distinguish between self-generated sensations, which are generally less behaviorally relevant or threatening, and externally generated sensations, which are more likely to require attention or defensive responses,” Ishiyama said.

Are you supposed to be able to tickle yourself?

Although most people can’t actually tickle themselves, experiments have shown that it is sometimes possible to trick the brain into feeling a slight tickle caused by itself.

For example, in a Journal of Cognitive Neuroscience In one study, when researchers used robotic tools to introduce tiny delays or spatial disruptions to self-induced touch, participants rated the sensations as slightly more ticklish. And the increase in tickling was found to be proportional to the error between the brain’s predicted sensory feedback and the actual sensory feedback it received.

A 2016 study in Consciousness and cognition also found that people with schizophrenia-like traits, known as schizotypy, tend to be more successful at tickling themselves.

What are the most ticklish parts of the body?

Not all skin is equally sensitive to tickling. Although personal preferences and tolerances vary, certain particularly ticklish body parts keep popping up in surveys and studies.

The soles of the feet are often ranked among the most ticklish places, followed by the armpits, neck and sides of the torso. Many people also consider their stomach and inner thighs to be quite ticklish.

Scientists still don’t know exactly why these spots are so ticklish. It may have something to do with skin sensitivity, nerve density, or even evolutionary factors such as protection of vulnerable parts of the body. But whatever the cause, these areas tend to produce the most intense reactions, especially when touched by someone else, according to the Cleveland Clinic.

Tickle is a game with a hint of fear

Tickling is not just a reflex. It is also a form of social play commonly seen in children and young animals, such as monkeys and rats.

“What I find most interesting about tickling is its ambivalent nature,” Ishiyama told Discover. “Rather than thinking that there are pleasant and unpleasant types of tickling, I view vigorous tickling as a form of ambivalent social play.”

And while our outward reaction to being tickled may seem like we’re purely having fun, the internal feeling is often more complex.

“Play is often seen as pure pleasure, but I think it usually includes some uncertainty or mild fear in a safe context. Tickling is not pure pleasure like massage,” Ishiyama added. “[And] maybe it’s that small amount of tension that makes it fun.

For example, tickling juvenile rats rarely results in negative responses, Ishiyama said.

“In contrast, when rats actively begin tickling, they often show brief fear-related behavior immediately after initiation, before the tickling occurs, similar to how you might feel nervous after buying a ticket for a roller coaster ride,” he added.

The biggest mystery in tickling research

Even with everything scientists know about brain mechanisms and behavioral patterns, tickling remains a “relatively specialized and understudied topic, so there are many open questions,” Ishiyama said. Discover. “If I had to name one, it would be this: why does simple touch to specific regions of the body reliably trigger bursts of laughter? »

“In other words, how tactile input is transformed into a vocal and emotional response and why this particular sensory-motor conversion has been preserved through evolution remains largely unexplained,” Ishiyama concluded.

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Article sources

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