I saw an interesting article about how lab rats react to researchers tickling them. I had no idea rats had a funny bone. They’ll even chase your hand to get tickled. When they’re tickled, they make laughing noises that are just under the threshold of human hearing, but the sounds can be heard when converted to our range of hearing. They like to be tickled on their bellies or backs.
What scientists have found is that an area in the brain called the periaqueductal gray (as medical students we had to learn about this area to pass anatomy class) that is associated with tickling and laughter. The upshot is that play is important for growing brains.
Many of us remember being tickled as children. We could get hysterical even if someone just approached us with hands outstretched, saying “kootchy kootchy koo.”
Something happens when we grow up and we lose that ticklish sensitivity. And you can’t tickle yourself to get that sensation.
Tickling sensitivity may go away, but a sense of humor usually doesn’t, at least for most of us. I can’t count the number of times Sena has caught me sort of stifling a chuckle over some funny thought that happens to cross my mind. I’m sure I look half-crazy. Sometimes I think I should come up with a semi-plausible explanation for this behavior (“Oh, I’m just being tickled by invisible extraterrestrials!”).
Scientists are still working on finding out why we’re ticklish. I don’t know exactly why we lose ticklishness as we grow up. But I don’t think building a tickling robot would fix it. It might be difficult to calibrate its finger strength, resulting in broken ribs and punctured lungs—at first. But those aren’t problems, just details to be worked out.
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