河边侃心理学（20）活煮青蛙

riverside
2010-05-15

动物保护主义者们，先不要砸我。现在没有人活煮青蛙啦，这只是一个传说。简单地说，活煮青蛙的说法讲的是，如果把青蛙扔进热水里，它会跳出来。但是，如果把它放进冷水里慢慢加热，青蛙会傻乎乎地继续待在那里直到被煮死。故事的寓意是，如果人的处境逐渐变差，往往会不积极去改变，直到处境显著变差甚至死亡。

比如，一个工人在工厂干了 26 年，最有四年就可以退休拿退休金了。工厂方面开始不断挑他的毛病，找他的麻烦，增加他的工作量，希望把他挤走。这种手段是万恶的资本家常用的，有点儿象我们中国说的软刀子杀人，杀人不见血。有些老板很狡猾，刚把新人招进来时，不让他们太难受，省得把他们气跑了找别的工作去。等新人慢慢习惯了，老板就开始逐渐地降薪水，增加工作量，他们会继续呆在这里受煎熬而不跳出去。特别是在现在这种劳动力供过于求，高失业率的时代，做老板的更可以加快水温上升的速度，不用太担心青蛙会蹦出去。

现代生物学家认为活煮青蛙的理论只是一个传说。他们认为， 如果慢慢加热，泡在水里的青蛙是会跳出来的。但是，相传 19 世纪有好事者做过实验，证实这个理论是正确的，如果加热进行得很慢很慢的话。 有趣的是，这么简单的实验，现在几乎没有人能够认真地做一次，用来证实或反驳 19 世纪的这个说法。有一些个著名大学的生物学教授凭自己的直觉和经验就武断地否定人家 19 世纪的实验结果。说话不依据实验结果，这在科学领域是很不寻常的事情。而读者居然能听之信之，不质询实验根据在哪里，也很不寻常。

为什么现代的科学家不肯做活煮青蛙的实验，我觉得，原因有几个，第一，这只是一种比喻，一种说法，没有必要较真到底青蛙被慢慢活煮时会不会跳出来。第二，这种实验也太简单了，做出来了也不能发表到有份量的杂志上。一个成名的大科学家做这个实验会被人笑掉大牙，一个刚起步的研究者做这个实验会被人挑毛病。第三，这样的实验在科学界得不到好评，却很可能会受到大众，特别是动物保护人士的抨击。

总结一下，活煮青蛙，如果加温足够慢，青蛙就会待在水里知道被煮死，这只是一个说法，不一定有实验依据。就算有实验依据，那也要保证加热的速度足够慢。但是，最重要的不是青蛙到底会不会被慢慢煮死，而是这是一个比喻。我们使用这个比喻来描述人对于环境的慢慢恶化不警惕，不反抗。我们所需要做的是，考虑一下自己作为一个个人，人类作为一个整体，是不是正处于一盆正在被缓慢加热的水中。我们是不是应该跳出来，什么时候跳，和怎么跳。核武器竞争和 全球气候暖化都是很好的例子，但是我就不在这里展开讨论了。

以下资料来自维基百科：
Biological background

Several experiments involving recording the reaction of frogs to slowly heated water took place in the 19th century. In 1869, while doing experiments searching for the location of the soul, German physiologist Friedrich Goltz demonstrated that a frog that has had its brain removed will remain in slowly heated water, but his intact frogs attempted to escape the water.

Other experiments showed that frogs did not attempt to escape gradually heated water. An 1872 experiment by Heinzmann demonstrated that a normal frog would not attempt to escape if the water was heated slowly enough, and this was corroborated in 1875 by Fratscher.

Goltz raised the temperature of the water from 17.5°C to 56°C in about ten minutes, or 3.8°C per minute, in his experiment which prompted normal frogs to attempt to escape, whereas Heinzmann heated the frogs over the course of 90 minutes from about 21°C to 37.5°C, a rate of less than 0.2°C per minute.[4] One source from 1897 says, "in one experiment the temperature was raised at a rate of 0.002°C. per second, and the frog was found dead at the end of 2½ hours without having moved."

In 1888 William Thompson Sedgwick explained the apparent contradiction between the results of these experiments as a consequence of different heating rates used in the experiments: "The truth appears to be that if the heating be sufficiently gradual, no reflex movements will be produced even in the normal frog; if it be more rapid, yet take place at such a rate as to be fairly called "gradual," it will not secure the repose of the normal frog under any circumstances..."

Contemporary experiments

Contemporary scientists have described the story as inaccurate. However, none have claimed to repeat (and invalidate) the specific 19th-century experiments that suggested that if the heating rate were gradual enough, the frogs would not attempt escape.

In 1995, Professor Douglas Melton, of the Harvard University Biology department, said, "If you put a frog in boiling water, it won't jump out. It will die. If you put it in cold water, it will jump before it gets hot — they don't sit still for you." Dr. George R. Zug, curator of reptiles and amphibians at the National Museum of Natural History, also rejected the suggestion, saying, "If a frog had a means of getting out, it certainly would get out."

In 2002 Dr. Victor H. Hutchison, Professor Emeritus of Zoology at the University of Oklahoma, with a research interest in thermal relations of amphibians, said that "The legend is entirely incorrect!” He described how the critical thermal maximum for many frog species has been determined by contemporary research experiments: as the water is heated by about 2°F, or 1.1°C, per minute, the frog becomes increasingly active as it tries to escape, and eventually jumps out if the container allows it.