Tickle U.

The psychology of tickling: The following quote comes from a Queen's University (Canada) press release about an article in PLoS Biology:

"'It's well-known that you can't tickle yourself … One explanation is that since all the sensations are completely predictable, we do "sensory attenuation" which reduces our touch perception.' Because people continually receive a barrage of sensory information, it's necessary to distinguish between what is caused by our own movements and what is due to changes in the outside world."

I'm betting that this "sensory attenuation" occurs in many other areas of life, too. Click to read the full Press Release and see pics of the Virtual Eye-Hand Coordination Laboratory.