双语有声阅读:Why Can't You Tickle Yourself 为什么自己

Have you ever thought about why people are ticklish¹? According to scientists, ticklishness² is a defense³ mechanism⁴ humans developed against bugs⁵, spiders, and other critters that may be touching⁶ our skin. Feeling ticklish is our built-in response to predators⁷ or threats, and combines the sensations of touch and pain.

The part of the brain that is associated with tickling⁸ is the cerebellum. It monitors our movements, but ignores movements not perceived as a threat. For example, we do not notice our vocal⁹ 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 tickle¹⁰ 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?

你有没有想过人为什么会怕痒？根据科学家的观点，怕痒是一种防御机制，是人类把它培养来对付那些可能接触我们皮肤的虫子、蜘蛛或其他生物。怕痒是我们对侵扰者或威胁产生的内在反应，它使触觉和痛觉结合起来了。

脑部与怕痒有关的部位是小脑。小脑监控我们的一举一动，但对其认为不具威胁性的活动，往往会忽视。举例来说，我们说话时不会察觉声带的振动，但是如有人触摸我们的肩膀时，我们可能会吓一跳。这种选择性的知觉或许就是我们无法自已哈痒的原因。

我们只会在察觉受到侵犯或攻击时才会觉得痒。如果试着替自己哈痒，脑部会自动预感到这种“攻击”从而使我们感觉不到惊吓。奇怪的是，即使有人知道他要被哈痒了，担心被人触摸，也会引起同样“怕痒”的反应。有些人甚至还没被哈到痒就先笑了。

英格兰近期做了一项关于人是否可以替自己哈痒的科学研究。自愿受测者接上脑部扫描仪，并用一块软泡沫绵给手掌哈痒。参与者在被哈痒和自行哈痒时，脑部扫描状况都受到监视。结果发现，在自行哈痒的过程中，小脑会向脑部的另一部位发出警告，使其预先防范，所以痒的感觉就消失了。

然而，研究人员也发现了可以替自己哈痒的方法。自愿者用遥控器操纵机器人，延迟片刻之后再让机器人为自己哈痒，自愿者就会觉得好像是别人在给他们哈痒。看来小脑在发出信号忽视即将到来的动作，然后将注意力转移到其他事物上。尽管只有零点二秒的时间差，脑部就会“忘记”你在替自己哈痒。所以自己给自己哈痒仍有可能，只不过需要依靠遥控器。谁知道接下来科学还会有什么新发现呢
 

1 ticklish   

adj.怕痒的；问题棘手的；adv.怕痒地；n.怕痒，小心处理

参考例句：

• This massage method is not recommended for anyone who is very ticklish.这种按摩法不推荐给怕痒的人使用。
• The news is quite ticklish to the ear,这消息听起来使人觉得有些难办。

2 ticklishness   

n.怕痒，小心处理

参考例句：

3 defense   

n.防御，保卫；[pl.]防务工事；辩护，答辩

参考例句：

• The accused has the right to defense.被告人有权获得辩护。
• The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。

4 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。

5 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

参考例句：

• All programs have bugs and need endless refinement. 所有的程序都有漏洞，都需要不断改进。 来自《简明英汉词典》
• The sacks of rice were swarming with bugs. 一袋袋的米里长满了虫子。 来自《简明英汉词典》

6 touching   

adj.动人的，使人感伤的

参考例句：

• It was a touching sight.这是一幅动人的景象。
• His letter was touching.他的信很感人。

7 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）

参考例句：

• birds and their earthbound predators 鸟和地面上捕食它们的动物
• The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》

8 tickling   

反馈，回授，自旋挠痒法

参考例句：

• Was It'spring tickling her senses? 是不是春意撩人呢？
• Its origin is in tickling and rough-and-tumble play, he says. 他说，笑的起源来自于挠痒痒以及杂乱无章的游戏。

9 vocal   

adj.直言不讳的；嗓音的；n.[pl.]声乐节目

参考例句：

• The tongue is a vocal organ.舌头是一个发音器官。
• Public opinion at last became vocal.终于舆论哗然。

10 tickle   

v.搔痒，胳肢；使高兴；发痒；n.搔痒，发痒

参考例句：

• Wilson was feeling restless. There was a tickle in his throat.威尔逊只觉得心神不定。嗓子眼里有些发痒。
• I am tickle pink at the news.听到这消息我高兴得要命。

11 tickled   

（使）发痒( tickle的过去式和过去分词 )； （使）愉快，逗乐

参考例句：

• We were tickled pink to see our friends on television. 在电视中看到我们的一些朋友，我们高兴极了。
• I tickled the baby's feet and made her laugh. 我胳肢孩子的脚，使她发笑。

12 foam   

v./n.泡沫，起泡沫

参考例句：

• The glass of beer was mostly foam.这杯啤酒大部分是泡沫。
• The surface of the water is full of foam.水面都是泡沫。

13 activated   

adj. 激活的 动词activate的过去式和过去分词

参考例句：

• The canister is filled with activated charcoal.蒸气回收罐中充满了活性炭。