Ever wonder why you can unmercifully tickle your two-year-old but not yourself? This question was posed to Sarah-Jayne Blakemore, at the Institute of Cognitive Neuroscience at University College in London and answered in Scientific American.
The answer lies at the back of the brain in an area called the cerebellum, which is involved in monitoring movements. Our studies at University College London have shown that the cerebellum can predict sensations when your own movement causes them but not when someone else does. When you try to tickle yourself, the cerebellum predicts the sensation and this prediction is used to cancel the response of other brain areas to the tickle.
This is absolutely fascinating for me. As someone makes a living examining bellies, I’ve found that asking a child to put their hand on top of my hand as I palpate markedly diminishes the tickle response. I saw an old pediatrician do this some years ago and picked up on it. Now I know why it works.
And by the way, when the doctor is examining your child, never comment that she’s ticklish. Suggestion, I’ve found, is a very powerful trigger in this case.
Via Shelley at Retrospectacle.