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Why Can't You Tickle1 YourselfHave you ever thought about why people are ticklish2? According to scientists, ticklishness3 is a defense4 mechanism5 humans developed against bugs6, spiders, and other critters that may be touching7 our skin. Feeling ticklish is our built-in response to predators8 or threats, and combines the sensations of touch and pain.
The part of the brain that is associated with tickling9 is the cerebellum. It monitors our movements, but ignores movements not perceived as a threat. For example, we do not notice our vocal10 chords moving when we speak, but we may jump if someone touches us on the shoulder. This selective perception is probably the reason why we cannot tickle ourselves.
We only feel ticklish if we detect a sense of invasion or attack. If we try to tickle ourselves, our brains anticipate this "attack" and prevent us from feeling panicked. Strangely enough, even if a person knows that they are about to be tickled11, the fear of being touched may cause the same "ticklish" reaction. Some people laugh even before being tickled. A scientific study was recently done in England to determine whether or not people can tickle themselves. Volunteers were attached to a brain-scanning device and were tickled on their palms with a piece of soft foam12 . The participants' brain scans were monitored while they were being tickled, and when they tickled themselves. It was found that during self-tickling, the cerebellum alerted another area of the brain about what to expect, so the ticklish feeling was diminished. Researchers did find a way, however, for people to tickle themselves. When volunteers activated13 a robot by remote control to tickle them after a short delay, the volunteers felt as if someone else were tickling them. It seems that the cerebellum sends a signal to disregard the forthcoming movement, then moves on to other things. Your brain "forgets" that you are tickling yourself—even with a delay as short as a fifth of a second. So it is possible to tickle yourself—but only by remote control. What will science discover next?
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1 tickle | |
v.搔痒,胳肢;使高兴;发痒;n.搔痒,发痒 | |
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2 ticklish | |
adj.怕痒的;问题棘手的;adv.怕痒地;n.怕痒,小心处理 | |
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3 ticklishness | |
n.怕痒,小心处理 | |
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4 defense | |
n.防御,保卫;[pl.]防务工事;辩护,答辩 | |
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5 mechanism | |
n.机械装置;机构,结构 | |
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6 bugs | |
adj.疯狂的,发疯的n.窃听器( bug的名词复数 );病菌;虫子;[计算机](制作软件程序所产生的意料不到的)错误 | |
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7 touching | |
adj.动人的,使人感伤的 | |
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8 predators | |
n.食肉动物( predator的名词复数 );奴役他人者(尤指在财务或性关系方面) | |
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9 tickling | |
反馈,回授,自旋挠痒法 | |
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10 vocal | |
adj.直言不讳的;嗓音的;n.[pl.]声乐节目 | |
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11 tickled | |
(使)发痒( tickle的过去式和过去分词 ); (使)愉快,逗乐 | |
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12 foam | |
v./n.泡沫,起泡沫 | |
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13 activated | |
adj. 激活的 动词activate的过去式和过去分词 | |
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