Not only are our sensory systems organized to detect change, but they are most tuned to stimuli that are unexpected and surprising. When you move your body and produce tactile sensations, these stimuli are less noticeable to you than are sensations produced by another individual. The sensations of your own legs touching one another when you cross your legs, for example, are generally less noticeable than a similar touch on your leg would be if someone sitting next to you brushed their leg against yours. Likewise, your reaction to your cat jumping onto your lap is likely to be much greater if you have your eyes closed when it happens. This differential response to surprising tactile stimuli appears to be a defense mechanism that has adaptive significance. It is probably also the reason why being tickled by someone else is more effective at producing an emotional reaction than trying to tickle yourself. Our enjoyment of being tickled generally diminishes as we age. This is likely due to the fact that adults are ____________________________, and hence are more difficult to surprise, than are children.
* tactile: 촉각의 ** tickle: 간질이다