:经济学人 dna：传递幸福的使者

幸福的遗传学

Transporter of delight

DNA：传递幸福的使者

Happiness is in your DNA; and different races may have different propensities for it

幸福其实隐藏在你的DNA当中。不同种族的人往往对幸福有不同的倾向。

Oct 15th 2011 | from the print edition

2011-10-15，来自印刷版
翻译／LukeJS

Born smiling?

天生幸福？

THE idea that the human personality is a blank slate, to be written upon only by experience, prevailed for most of the second half of the 20th century. Over the past two decades, however, that notion has been undermined. Studies comparing identical with non-identical twins have helped to establish the heritability of many aspects of behaviour, and examination of DNA has uncovered some of the genes responsible. Recent work on both these fronts suggests that happiness is highly heritable.

人类出生时如同一张白纸，只有后天的经验才能在上面留下各种痕迹。这一观点几乎统治了20世纪后半个时期。然而，近20年来，这一观点的影响力已大大减弱。对同卵双生子和异卵双生子的研究已经揭示出许多行为的遗传性，对DNA的检测更是显示出基因的决定作用。最近在这两个前沿领域中的研究工作表明，幸福这一主观感受同样在很大程度上是可遗传的。

As any human being knows, many factors govern whether people are happy or unhappy. External circumstances are important: employed people are happier than unemployed ones and better-off people than poor ones. Age has a role, too: the young and the old are happier than the middle-aged. But personality is the single biggest determinant: extroverts are happier than introverts, and confident people happier than anxious ones.

众所周知，有许多因素影响着人们是否感到幸福。外在的环境是重要的：找到工作的人比没有工作的人要幸福，生活条件好的人比穷人要幸福。年龄也是一大因素：年轻和年老的人比中年人要幸福。但人格则是最重要的影响因素：外向的人比内向的人幸福，自信的人比焦虑的人幸福。

That personality, along with intelligence, is at least partly heritable is becoming increasingly clear; so, presumably, the tendency to be happy or miserable is, to some extent, passed on through DNA. To try to establish just what that extent is, a group of scientists from University College, London; Harvard Medical School; the University of California, San Diego; and the University of Zurich examined over 1,000 pairs of twins from a huge study on the health of American adolescents. In “Genes, Economics and Happiness”, a working paper from the University of Zurich’s Institute for Empirical Research in Economics, they conclude that about a third of the variation in people’s happiness is heritable. That is along the lines of, though a little lower than, previous estimates on the subject.

越来越多的证据表明，人格与智力一样，至少部分上是可遗传的。因此，我们可以推断，幸福与否的主观感受，在某种程度上也是能够通过DNA得到传递的。为了得出这种程度的大小，一组来自伦敦大学学院、哈佛医学院、加州大学圣迭戈分校和瑞士苏黎世大学的科学家们，从一项对美国青少年健康状况的大型调查中，收集了1000对双生子的资料。在苏黎世大学经济学实证研究所发表的一篇名为《基因、经济学与幸福》的工作论文中，研究者们得出结论：在幸福感的总变异中，约有三分之一是可遗传的。虽然程度比预计稍低，但这一结论与之前的研究预想是一致的。

But while twin studies are useful for establishing the extent to which a characteristic is heritable, they do not finger the particular genes at work. One of the researchers, Jan-Emmanuel De Neve, of University College, London, and the London School of Economics, has tried to do just that, by picking a popular suspect—the gene that encodes the serotonin-transporter protein, a molecule that shuffles a brain messenger called serotonin through cell membranes—and examining how variants of that gene affect levels of happiness.

尽管对双生子的研究能够显示出某种特征的遗传性，但它并不能指出起作用的基因到底是什么。血清素（5-羟色胺）载体蛋白是一个能够在细胞膜之间传递血清素这一大脑信使的蛋白分子，而指导合成这一蛋白分子的基因便是学界普遍怀疑能够影响幸福感的基因。 来自伦敦大学学院与伦敦经济学学院的Jan-Emmanuel De Neve是这项研究的一位研究员，他便通过研究以上基因，检验了这一基因的变异如何影响了不同人的幸福水平。

Serotonin is involved in mood regulation. Serotonin transporters are crucial to this job. The serotonin-transporter gene comes in two functional variants—long and short. The long one produces more transporter-protein molecules than the short one. People have two versions (known as alleles) of each gene, one from each parent. So some have two short alleles, some have two long ones, and the rest have one of each.

血清素还参与了情绪的调控过程，而血清素载体则在这一过程中起到重要作用。血清素载体基因有两种功能意义上的不同形式：长型和短型。长型的基因能够比短型的基因产生更多的血清素载体蛋白分子。人类拥有两套这样的基因（亦即等位基因），一条来自父亲，一条来自母亲。因此有些人有两条短基因，有些人有两条长基因，而有些人则是一长一短。

The adolescents in Dr De Neve’s study were asked to grade themselves from very satisfied to very dissatisfied. Dr De Neve found that those with one long allele were 8% more likely than those with none to describe themselves as very satisfied; those with two long alleles were 17% more likely.

De Neve博士要求研究中被调查的青少年对自己进行评价，评分从非常满意到非常不满意。De Neve博士发现，比起两条基因都是短基因的人，有一条长基因的人将有8%的概率更倾向于把自己评价为非常快乐，而有两条长基因的人则有17%的概率更倾向如此做。

Which is interesting. Where the story could become controversial is when the ethnic origins of the volunteers are taken into account. All were Americans, but they were asked to classify themselves by race as well. On average, the Asian Americans in the sample had 0.69 long genes, the black Americans had 1.47 and the white Americans had 1.12.

这一结果是有趣的。如果考虑到这些被调查者的种族，该研究就更具有争议了。所有的被调查者均为美国人，但研究要求他们区分自己的种族。平均来说，样本中的亚裔美国人有0.69条长基因，非裔美国人则为1.47条，而美国白人则为1.12条。

That result sits comfortably with other studies showing that, on average, Asian countries report lower levels of happiness than their GDP per head would suggest. African countries, however, are all over the place, happinesswise. But that is not surprising, either. Africa is the most genetically diverse continent, because that is where humanity evolved (Asians, Europeans, Aboriginal Australians and Amerindians are all descended from a few adventurers who left Africa about 60,000 years ago). Black Americans, mostly the descendants of slaves carried away from a few places in west Africa, cannot possibly be representative of the whole continent.

这一结果与其他的研究也是相当吻合的。平均而言，亚洲国家的国民幸福感比人均GDP所显示的更低。然而，非洲国家的国民则普遍更倾向于幸福。但这一结果也不令人惊讶。非洲是基因最多样化的大陆，因为它是人类进化的起源地（亚洲人、欧洲人、澳洲土著人以及美洲人都是非洲人在约60000年前离开非洲后所形成的后代）。美国黑人大多数是非洲西部一些地区的奴隶迁移过来而形成的后代，也许并不能代表整个非洲大陆的人种。

That some populations have more of the long version of the serotonin-transporter gene has been noticed before, though the association has previously been made at a national, rather than a racial, level. In a paper in the Proceedings of the Royal Society, published in 2009, Joan Chiao and Katherine Blizinsky of Northwestern University, in Illinois, found a positive correlation between higher levels of the short version of the gene and mood disorders (China and Japan have lots of both) and with collectivist political systems. Their hypothesis is that cultures prone to anxiety tend towards systems that emphasise social harmony and away from ones that emphasise individuals’ independence of each other.

以前一些研究已经指出，一些人种具有更多的长型血清素载体基因。然而在以往，这一联系往往是在国家层面而不是种族层面提出的。《英国皇家学会学报》于2009年发表的一篇论文中，来自伊利诺伊州西北大学的作者Joan Chiao和Katherine Blizinsky，发现了情绪失衡与短基因数量之间的正相关关系（中国人与日本人的短基因数量较多），同时短基因数量与集体主义的政治制度也存在正相关关系。他们的研究假设是，强调社会和谐的文化其焦虑倾向高，而强调个人独立的文化则其焦虑倾向低。

This latter study may be a few steps too far along the road to genetic determinism for some people. But there is growing interest in the study of happiness, not just among geneticists but also among economists and policymakers dissatisfied with current ways of measuring humanity’s achievements. Future work in this field will be read avidly in those circles.

对某些人来说，后一项研究也许与基因决定论离题太远。然而，各界对幸福感的研究兴趣不断加深，这不仅仅是在遗传学家之间，同样也存在于经济学家，以及那些对人类成果的现有衡量方式感到不满的政策制定者之间。未来在这一领域的研究工作，将主要围绕在这些方面。

from the print edition | Science and technology

来自印刷版，科技模块
翻译／LukeJS