Why Don’t We Laugh When We Tickle Ourselves?

Suppose you’re walking down a deserted lane, deeply engrossed in figuring out the meaning of the movie Inception (in short, minding your own business). All of a sudden, from out of nowhere, your goofy friend Paul walks up to you and tickles you on the sides of your ribcage. What happens next? Maybe something like this:


However, imagine the same scenario, but instead of Paul, you are trying to tickle yourself in the same place with your own hands. Now what happens? Umm… maybe something like this?

Bottom Line: You Can’t Tickle Yourself

But why is that? Allow me to explain.

The part of the brain that responds to different stimuli, such as touch, heat, light, and so on is called the “Somatosensory Cortex”. Therefore, when someone tickles you, this part becomes activated and your body performs a reflex action, such as jerking your body away from the source of the touch, as well as laughing uncontrollably. Some people may even have violent reactions, spasming in uncontrolled movements to avoid the unwanted touch.

Cerebrum_lobes.svg

But why can’t you tickle yourself, if someone else can (and make you laugh)?

The inability to tickle yourself is due to a tiny little part of your brain called the cerebellum. This is the part of your brain that controls the motor functions of your body. Therefore, it is the cerebellum that commands the different parts of your body to make every kind of motion.

Now, when you move your hand to tickle yourself, the cerebellum in your brain knows that there is a voluntary motion going on in the body (your fingers moving). What it does, in turn, is overshadow the signals of the Somatosensory Cortex, so you don’t feel anything that resembles the unexpected stimuli of someone else tickling you. Essentially, you are trying to trick your brain, which is never a good idea.

Check out the video below, which explains this peculiar human phenomenon:

References:

  1. Why Can Not You Tickle Yourself? – University of California, Santa Barbara Science Line
  2. How Stuff Works
  3. Scientific American
The short URL of the present article is: http://sciabc.us/Xc3CJ
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Ashish is a Science graduate (Bachelor of Science) from Punjabi University (India). He spends a lot of time watching movies, and an awful lot more time discussing them. He likes Harry Potter and the Avengers, and obsesses over how thoroughly Science dictates every aspect of life… in this universe, at least.

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