Why do we laugh when tickled?

Why tickling makes us laugh is one of those weird, unexplained questions which can only be explained by brainy scientists.

Pain and touch receptors

Molecular biology and genetics boffin Dr Emily Grossman (a science educator based in the UK) says even science can’t give a precise definition of tickling because the sensation involves a series of neurological and sensory elements.

Biologically speaking, there is no evidence to show we have specialised “tickle” receptors in our skin, adds medical physiologist at Stellenbosch University Dr Derek van Vuuren. “Rather, it seems that the perception of tickling is communicated through a combination of pain and touch receptors,” he explains.

Read: At 4 months, babies don't relate touch to other senses

It’s in the brain

Dr Grossman, in a Royal Institution’s video on the science behind tickling, explains that we laugh when we’re tickled because "both tickling and laughing activates the Rolandic operculum – a part of the brain that controls facial movement as well as vocal and emotional reactions".

Moreover, Dr van Vuuren says the area of your brain involved in laughing at a funny joke is "not the same as the area associated with laughter when being tickled".

Scientists believe the reason for this difference is because tickling also activates the hypothalamus, which controls body temperature, hunger, tiredness, sexual behaviour and instinctive reactions like the “fight or flight” mechanism.

Watch: How to stop yourself from being ticklish

Even stranger, stimulating the hypothalamus helps the body anticipate pain, say neuroscientists at the University of Tübingen in Germany, which might explain why someone may accidentally lash out at their tickler.

They believe our response to tickling goes back to earliest human evolution, and that it has become a defensive mechanism to indicate submissiveness, calm a tense situation and prevent us from getting hurt.

Why can’t I tickle myself?

We know that we laugh when tickled, especially in those sensitive areas on the stomach, near the throat or under the arms and feet, so why doesn’t it work if you tickle yourself?

Dr Grossman explains that the cerebellum at the back section of the brain makes predictions on how the sensation will feel and where it will occur, so it actually suppresses the tickle response. “This is supported by studies that have found when people try to tickle themselves, activity in the area of the brain linked to the tickle response decreases.”

In a nutshell: Because your brain continually filters out unimportant information, it is aware it does not need to produce a response to the action, so it simply doesn’t waste time interpreting the signals from a self-tickle.

Tackling potential ticklers

So if you are one of those people who really hate being tickled, can this knowledge help you in any way? It so happens that you can actually control your response to being tickled!

Next time your bratty brother or creepy classmate reaches out to torment you with merciless tickling, simply place your hands on top of theirs. “This allows your brain to better predict the sensation of their hands, therefore it will suppress and ultimately protect your tickle response,” advises Dr Grossman.

Read more:

Period pains may alter the brain

Why bumping your funny bone hurts

This new procedure could repair damaged nerves in days

Image: from iStock

^References 

^{1. http://www.european-biotechnology-news.com/pictures-videos/mix/why-do-we-laugh-when-tickled.html}

^{2. http://scienceline.ucsb.edu/links/links.php}

^{3. http://www.medicaldaily.com/pulse/tickle-tickle-science-behind-being-ticklish-and-how-overcome-it-329802}

^{4. http://www.bbc.com/future/story/20140131-why-do-we-laugh-when-tickled}

^{5. https://sites.psu.edu/siowfa15/2015/10/15/why-are-you-so-ticklish/}