Tickling is a peculiar sensation. There are actually two distinct types of tickles. Knismesis is the light, feathery touch, like an insect crawling on your skin. However, what we typically think of as tickling, the kind that elicits laughter and squirming, is called gargalesis. This is the more intense tickle targeting areas like the ribs or armpits.
Think about the experience of being tickled. It’s a strange mix of reactions. You laugh, sometimes uncontrollably, which is usually associated with joy and amusement. Yet, simultaneously, you might squirm, try to escape, push the tickler away, and even beg them to stop – all while still giggling and shrieking. This contradictory response begs the question: Is tickling enjoyable or not?
The laughter induced by tickling is fundamentally different from the laughter we experience when we hear a joke or see something funny, explains neuroscientist Alicia Walf from Rensselaer Polytechnic Institute. Humor-induced laughter is processed in the frontal lobe, the brain region responsible for memory and abstract thought.
In contrast, the sensation of being tickled is processed in the limbic system, the brain’s emotional center. According to Walf, these emotions can be both positive and negative, but they are very basic, primal reactions. The limbic system is an evolutionarily older part of the brain, primarily associated with the “fight or flight” response.
Unpacking the Tickle Response: Why Does It Exist?
Despite knowing the neurological pathways involved in tickling, the fundamental reason why we are ticklish remains somewhat of a scientific puzzle. One prominent theory suggests that tickling serves a crucial role in social bonding. Walf highlights that we generally dislike being tickled by strangers, indicating a social context to this sensation.
Tickling may also play a significant part in development. Babies and young children are notably more ticklish than adults, and adults seem instinctively inclined to tickle them. Walf suggests that this interaction might be crucial for training a baby’s sensory systems from birth. Tickling could help infants learn to differentiate between harmless sensations and potentially threatening ones.
This developmental theory could explain why we are particularly ticklish in vulnerable areas like the ribs, which protect vital organs.
“It’s beneficial to train that area of the body to recognize ‘OK, this type of touch is acceptable,’” Walf explains, “but when the sensation escalates beyond a certain point, it becomes unacceptable.”
Therefore, our tickle response might be a social mechanism for exploring and defining personal boundaries. A gentle tickle can be playful and fun, but excessive tickling quickly becomes unpleasant. For infants, over-tickling might lead to crying, while adults might react by pushing away or even striking the tickler.
Psychologist Robert Provine, known for his research on laughter, proposed that tickle-induced laughter could be a form of preverbal communication between infants and caregivers. Tickling may also assist infants in gradually distinguishing themselves from others, differentiating “me” from “mom.”
Walf, whose research focuses on stress, emphasizes the situational nature of ticklishness.
“The same type of touch can be processed entirely differently by the brain depending on the context,” she notes.
If you are stressed or in a negative mood, a playful tickle might not trigger any giggles. Instead, it could simply feel irritating.
Read More: Do Rats Laugh? Researchers Tickled Rats to Reveal the Brain’s ‘Play Zone’
The Mystery of Self-Tickling: Why Is It Impossible?
While we react strongly to being tickled by others, most people find it impossible to tickle themselves. Research suggests that the inability to self-tickle is partly due to the lack of surprise involved. (Consider how effective it is to ask someone to tickle you – the anticipation often diminishes the ticklish sensation). However, there is a more complex neurological explanation.
Tickling sends sensory signals from the body to the brain. However, Walf explains that there is also a descending neural pathway that can dampen this sensation. This pathway is activated in situations like when we are in a bad mood or uncomfortable with the person tickling us. Crucially, we are always aware when we are touching ourselves.
“We possess very robust body maps, allowing us to anticipate and control self-generated sensations, thus muting the tickle pathway,” she explains.
The inability to tickle oneself further supports the idea that ticklishness is related to learning to distinguish self from others. Once this distinction is established, self-tickling becomes ineffective.
Read More: Why We Can’t Tickle Ourselves
Article Sources
Our writers at Discovermagazine.com utilize peer-reviewed studies and reputable sources for our articles, and our editors ensure scientific accuracy and maintain high editorial standards. Below are the sources referenced for this article:
Avery Hurt is a science journalist who contributes to Discover and various other publications including National Geographic, Science News Explores, Medscape, and WebMD. She is also the author of “Bullet With Your Name on It: What You Will Probably Die From and What You Can Do About It,” and several books for young readers. Hurt’s background in philosophy and her interest in neuroscience, consciousness, and AI inform her science writing.
