It's a question that's been plaguing mankind for centuries: Why is it so hard to tickle yourself? Now, science may have the answer.
Researchers say the killjoy appears to be the cerebellum which is found in the lower back part of the brain. It apparently tells the rest of your brain that "it's just you...don't get excited."
Scientists say their study builds on earlier findings that show the brain already knows what a person will feel when the body does something. That way it ignores the expected sensation of pressure on the soles of your feet while walking, and saves its attention for more important things like the feeling of a foot bumping a stone.