明明撓的是別人，為啥自己會笑個不停

It’s perfectly normal for someone to laugh uncontrollably when tickled, although some of us are more ticklish than others, but researchers at the University of California, San Diego, recently reported the unusual case of a woman who would burst into laughter when seeing other people being tickled.

被人撓癢癢時，你會控制不住地笑個不停。這很正常。盡管每個人的敏感程度存在差異，但加州大學(xué)圣地亞哥分校的研究人員最近報告了一種非同尋常的病癥：一位女性只要看到別人被撓癢癢，自己就會無法抑制地笑個不停。

Referred to only as TC, the woman was apparently seeking help for her bizarre condition – whenever she saw someone getting tickled, she could feel the sensation on her own skin and would start to laugh uncontrollably as if she was the one getting tickled. Researchers conducted a series of experiments to explore the bizarre phenomenon further and concluded that the woman suffered from a rare condition known as mirror-touch synaesthesia. It is believed to be caused by mirror neurons, connectors in the brain that react the same way when an event is experienced or when it’s simply observed.

他們稱這位女性為TC。她因為自身的奇怪癥狀而尋求醫(yī)學(xué)幫助。只要看到別人被撓癢癢，她就會在自己的皮膚上產(chǎn)生感覺，然后開始大笑不止，仿佛她才是被撓癢癢的那個人。為探究這種奇怪現(xiàn)象，研究人員進行了一系列實驗，最后得出結(jié)論：她患有一種罕見癥狀——鏡像觸覺聯(lián)覺?？茖W(xué)家認(rèn)為，這是由“鏡像神經(jīng)元”引起的。鏡像神經(jīng)元是大腦里的一群神經(jīng)細(xì)胞，能夠在體驗或僅僅觀察某些事件時產(chǎn)生反應(yīng)。

To make sure that TC’s fits of laughter were caused by mirror-touch synaesthesia and not because she simply found the situation of another person being tickled funny, researchers at the University of California, San Diego, tested the woman’s reactions in various circumstances, like seeing other people touch different surfaces, put their hand in ice water, or be tickled. They also tested her reactions to jokes and funny video clips, and established that she had a normal sense of humor.

她的癥狀是由鏡像觸覺聯(lián)覺引起的，還是由于她覺得別人被撓癢癢的場景很滑稽?為探究此問題，研究人員在各種場景中測試她的反應(yīng)，例如看到他人觸碰不同物體的表面、把手放進冰水里、被撓癢癢等。此外，他們也測試了她對笑話和搞笑視頻的反應(yīng)，證實她具有正常的幽默感。

The study showed that whenever she watched other people getting tickled, TC reacted with uncontrollable laughter, as if she was experiencing the tickling herself. The sensation was so realistic that she would rub her armpits in an attempt to neutralize it.

研究結(jié)果顯示：只要看到別人被撓癢癢，她就會無法抑制地笑個不停，仿佛自己正被人撓癢癢。她的感覺非常真實，以至于她會摩擦自己的腋窩，企圖緩解這種感覺。

The reaction to second-hand tickling was more intense under certain circumstances. For example, the tickling sensation appeared to be considerably more acute when TC could see the facial expressions of the volunteers being tickled during the experiments, or if the volunteer was someone she knew, or who looked like her. Researchers note that the laughter was most extreme when she watched videos of herself being tickled.

在某些情況下，這種反應(yīng)會更加劇烈，例如：當(dāng)她看到志愿者(被撓癢癢者)的面部表情時;當(dāng)志愿者是她認(rèn)識的人時;當(dāng)志愿者和她長相類似時。在觀看自己被撓癢癢的視頻時，她的反應(yīng)最為劇烈。

Similar results were recorded in experiments where TC watched other people touching velvet, brushes, silk, and table surfaces. She reported experiencing the same sensations as if she was the one touching them. When seeing volunteers dunk their hand in ice water, she reported feeling the wet sensation but not the low temperature.

當(dāng)她看到志愿者觸摸天鵝絨、刷子、絲綢、桌子等物體的表面時，她也會產(chǎn)生同樣的觸感，仿佛自己正在觸摸它們。當(dāng)她看到志愿者將手放進冰水里時，她會產(chǎn)生濕潤感，但沒有產(chǎn)生低溫感。

Researchers explained that mirror neurons in TC’s brain worked a bit differently than they do in most people’s brains. These connectors are activated when we or someone we see is being touched, but the brain usually blocks their response when it’s someone else experiencing the sensation, essentially separating the self from others. In TC’s case, the blocking signals sent by her brain are weaker, which causes her to experience other people’s sensations as if they were her own.

研究人員解釋道，她的鏡像神經(jīng)元和常人略有不同。當(dāng)我們自身被觸碰或我們看到某人被觸碰時，這些神經(jīng)元會被激活。不過，在第二種情況下，大腦通常會封鎖反應(yīng)，以區(qū)分自我和他人。但她的封鎖信號比較弱，這導(dǎo)致她能夠真實地體驗到他人的觸感。

Studies suggest that only between 1.6% and 2.5% of the human population experience some form of mirror-touch synesthesia, but the degree of empathy can vary greatly, as can the sensations.

研究顯示，只有1.6-2.5%的人會體驗到某種形式的鏡像觸覺聯(lián)覺，但程度和感覺存在極大差異。