为什么笑会传染？

"Laugh and the world will laugh with you."2） That legendary line by Ella Wheeler Wilcox still holds true. Just like yawning， laughing is also highly contagious， but laughing is one contagious disease that we love and we gladly spread it to others. In fact， even the sound of someone laughing can make you let out a gut-busting3） chuckle4）.

How many times has it happened that you laughed your heart out5） at a movie theatre， but when you watched the movie alone again on TV， you didn&apos；t find it that funny， or at least didn&apos；t laugh nearly as loud？ It&apos；s because you were watching the movie by yourself， but that isn&apos；t the same thing that happens when we experience humor in larger groups. So what makes laughing so contagious？ Why do we end up laughing with other people even if we don&apos；t find the joke all that funny？

Why Do We Laugh？

People may laugh for various reasons， such as if they like a joke， if they see their friend take an awkward tumble6）， or if they experience anything else that might tickle their funny bone7）.

Studies have shown that laughing has been passed on to humans from our ancient primate8） ancestor. For our ancestors， laughter was a process of strengthening the bond between them. People laugh when they feel free and are comfortable with one another， so laughter definitely increases bonding between people， just as it did for our ancestors.

Why Is It Contagious？

The way a person reacts to a sound is dependent on the brain&apos；s premotor cortical9） region. This region is responsible for how the muscles in the face react to the corresponding sounds. University College of London conducted a study on certain volunteers where they played different sounds to them and measured their brain&apos；s reaction to the sound.

It was seen that responses were higher for positive sounds， such as laughing or the sound of triumph， and were much lower for negative sounds like screaming or retching10）. This suggests that humans are more susceptible11） to the sound of laughter as compared to negative sounds. This explains the reason for our involuntary12） smile when we see other people laughing.

There is a famous case of the contagious nature of laughing known as the Tanganyika laughter epidemic13）. In 1962， three girls studying in a boarding school14） in a village in Tanganyika （now Tanzania） began to laugh， and soon it spread to the whole school. Eventually， it affected about 95 of the 159 pupils.

This natural response that we have to laughter is the reason why pre-recorded laughter is frequently put on sitcoms15）， as this increases the chance of inducing laughter from the audience. Laughter therapy also works on the same principle： when you see many people laughing， you involuntarily end up laughing too！

It is often said that laughter is the best medicine， as it has many benefits for human health. In that case， I just have one thing to say： laugh and make the whole world laugh with you.

為什么笑会传染？为什么听到别人笑，你也会不由自主地扬起嘴角？为什么明明很生气，可对方含着笑向你赔礼道歉的时候，你就再也生不起气来？笑真是个奇妙的东西，好好的就能连成一片。至于其背后的一部分原因，科学家们已经有所发现，你想知道吗？

“你欢笑，这世界陪你一起欢笑。”埃拉·惠勒·威尔科克斯这一脍炙人口的诗句仍然在理。就像打呵欠一样，笑也有很强的传染性，但笑这种“传染病”人见人爱，还乐意传染给别人。事实上，甚至是别人的笑声也能让你开怀一笑。

有多少次，你曾遇到下面的情况？你在电影院会捧腹大笑，可当你独自在电视上再看这部电影时，你却不觉得那么好笑了，或者至少笑得没那么欢了。这是因为此时你是独自一人看这部电影，而当我们在人数较多的人群之中体验幽默时，情况就不一样了。那么，是什么让笑这么容易传染？为什么我们即便不觉得某个笑话那么好笑，可最终还是会和其他人一起笑呢？

为什么我们要笑？

人们发笑可能有很多不同的原因，比如说可能是喜欢一个笑话，可能是看到朋友跌倒出糗，或者遇到了其他什么可能会戳中笑点的事情。

研究表明，笑是人类从我们那古老的灵长类动物祖先那里遗传来的。对我们的祖先来说，笑是强化彼此情感关系的一种方法。当人们彼此相处感到无拘无束、轻松愉快时，他们就会笑。所以，笑无疑会增进人们之间的感情，就像其对我们祖先的作用那样。

为什么笑会传染？

人对声音的反应取决于大脑的前运动皮层区。这个区域负责决定脸部的肌肉如何对相应的声音做出反应。伦敦大学学院做过一项研究，研究人员给一些志愿者播放了不同的声音，并测量了他们的大脑对这些声音的反应。

研究发现，志愿者对积极的声音（比如笑声或是获胜的欢呼声）反应较强，而对消极的声音（像尖叫声或呕吐声）反应较弱。这表明，与听到各种消极声音相比，人类更容易受到笑声的影响。这就解释了为什么当我们看到别人笑时，我们也会不由自主地笑起来。

有个著名的事例可以说明笑的传染本质，这个事例被称作坦噶尼喀大笑病。1962年，在坦噶尼喀（现称坦桑尼亚）某村一所寄宿学校就读的三个女孩笑了起来，她们的笑很快传染到了整个学校。最终，159名小学生中约有95名学生都受到影响笑了起来。

因为我们会对笑产生这种自然反应，所以情景喜剧里常常加入预先录制的笑声，以便更多地引发观众的笑声。笑声疗法也是同样的道理：当你看到很多人笑的时候，你最终也会不由自主地笑起来！

常言道，笑是最好的良药，因为笑能给人们的健康带来诸多益处。既然如此，我只有一句话想说：笑吧，让全世界陪你一起欢笑。

1. contagious [k?n?te?d??s] adj.（感情、态度等）感染性的

2. 这句话出自美国作家、诗人埃拉·惠勒·威尔科克斯（Ella Wheeler Wilcox， 1850～1919）的诗歌《孤独》（Solitude），诗歌的前两句为：Laugh， and the world laughs with you； /Weep， and you weep alone.

3. gut-busting： 让人捧腹大笑的

4. chuckle [?t??kl] n. 轻轻的笑

5. laugh one&apos；s heart out： 捧腹大笑；纵声大笑

6. tumble [?t?mbl] n. 跌倒；摔跤

7. funny bone： 幽默感

8. primate [?pra?me?t] adj. 灵长类（动物）的

9. premotor cortical： 大脑前运动皮层的

10. retch [ret?] vi .作呕；恶心

11. susceptible [s??sept?bl] adj. 易受……影响的

12. involuntary [?n?v?l?ntri] adj. 不由自主的

13. Tanganyika laughter epidemic： 坦噶尼喀大笑病。1962年1月30日，新兴国家坦噶尼喀（现在是坦桑尼亚的大陆部分）有三个女孩子因为一个笑话大笑出声，传染了整个学校，影响了全校一半以上的学生，并在当地传染开来。这些学生突然爆发出笑声，笑到流泪、昏倒、出疹子。有专家认为这与压力有关，但具体原因不详。

14. boarding school： 寄宿学校

15. sitcom [?s?tk?m] n. 情景喜剧