“Tickle, tickle, tickle.”

With just those three words, you know what’s coming. Mom, dad, sister or brother is about to send you into a laughing, screaming fit. They’re going to tickle you. But why can’t you tickle yourself? NPR helps us explain.

You can't surprise your brain

The answer is fairly simple: You can’t surprise your own brain. 

Our brains are constantly making predictions about what’s going to happen, and we respond accordingly. If we know how, when and where we are going to tickle ourselves, we can’t be surprised, and there is no laughing, screaming fit associated with it. 

But what if you could trick your brain into being surprised? 

To find out if it is possible to tickle yourself, professor Jakob Hohwy of Monash University in Australia conducted an experiment of illusion and reality. In an interview with NPR host Rachel Martin, he explained that to conduct this experiment, you sit at a table, put your hand up on the table and cover it. Next to your hidden real hand, place a fake hand – a stuffed dishwashing glove – on the table and keep it visible. Then ask another person to tap the rubber hand and the hidden hand in synchrony. After a while, you will get an illusion that the touch you can feel is located on the rubber hand.

Professor Hohwy points out that when it comes to our senses, sight trumps feeling. So while it isn’t possible to tickle yourself if you’re visually aware of your body, it is possible to trick yourself into thinking someone else is tickling you.