Science & Technology at Scientific American.com: Ask the Experts: Biology: Why can't a person tickle himself?

A few days ago I told a colleague about the curious fact that you can't seem to be able to tickle yourself. When someone tickles you, you felt ticklish, however when you try to tickle yourself, you don't seem to feel it.

This is one of our body's interesting mysteries. I read about it years back and science couldn't answer it....yet. And now the answer is here!

I wish they described the robot test in more detail though. What configuration and how to program the delay mentioned.