The Dark Side of Cultural Evolution
文化进化的黑暗面
作者：Peter Turchin @ 2012-5-17
译者：林婵娟(@Standingbesideyou) 一校：林翠
来源：evolution-institute.org， https://evolution-institute.org/blog/the-dark-side-of-cultural-evolution-2/
Cultural evolution is what created the – in many ways – wonderful societies that we live in. It created the potential to free our lives from hunger and early death, and made possible the pursuit of science and art. But cultural evolution also has a dark side, in fact, many ‘dark sides.’
文化进化在许多方面造就了人类赖以生存的美好社会，它让我们有望从饥饿和早夭的命运中解脱出来,也使追求科学和艺术成为可能。但是文化进化也有其黑暗面，事实上，其背后“黑影重重”。
Clearly domestication of plants and animals is what made our civilization possible. All sufficiently complex societies are possible only on the basis of agriculture. But we have paid, and continue paying a huge price for this advance of human knowledge and technology. This idea was brought home to me as a result of several conversations I had with Michael Rose during the Consilience Conference at St. Louis, which I talked about in my previous blog.
众所周知，种植和畜牧使我们发展起文明。任何一个有效运转的复杂社会，都离不开农业基础。然而，过去和如今我们人类都为知识和科学的进步付出了巨大的代价。我开始确信这点，得益于在圣路易斯举行的学科融通研讨会上和Mickael Rose的几次谈话，我在之前的博客上写过。
Michael is an evolutionary biologist at the university of California at Irvine, who studies aging from the evolutionary perspective. I actually read his book Evolutionary Biology of Aging some twenty years ago, but never met him until two weeks ago.
Michael 是加利福尼亚大学欧文分校的一位进化生物学家,致力于从进化的角度研究衰老。大约20年前我就读过他的书《衰老的进化生物学》，但直到两周前才有幸和他会面。
One way people talk about the price of civilization is in terms of evolutionary mismatch (which is
one of the focus areas at the Evolution Institute). The idea is that our bodies and minds evolved during the
Pleistocene, when we lived in small groups of hunter-gatherers. Now we live in a dramatically different environment, and that causes all kinds of problems. The psychological aspect of the problem was recently discussed by Robin Dunbar and commentators on his Focus Article. The physiological problems include rampant obesity, heart disease, and diabetes.
探讨文明发展代价的一种方式是研究进化失配（这也是本站Evolution-Institute.org所专注的领域之一）。失配理论的意思是，人类身心进化的过程发生在旧石器时代，那时我们生活在小型狩猎－采集群体中。而现在我们却面临着截然不同的生存环境，这导致了各种各样问题。最近，Robin Dunbar写的专题文章，以及收到的评论，探讨了失配问题中的心理方面。而生理方面的问题则包括日益严重的肥胖症、心脏病、糖尿病等。
There is currently no consensus on the role of changing diet and other aspects of lifestyle, most notably exercise, in causing modern-day health problems. Some people argue that our Plestocene bodies are not adapted to high-calorie diets and sedentary life-styles of today.
人类饮食和生活方式（尤其是运动方式）的改变，在当今健康问题中到底扮演了什么角色，尚未取得共识。有些人认为，我们在旧石器时代进化出来的身体，并不适应现如今高卡路里的饮食结构和久坐不动的生活方式。
On the other hand, agriculture was invented roughly 10,000 years ago. 400 generations is not an insignificant length of time for evolution to do its thing. Some anthropologists (including another participant of the Consilience conference,
Henry Harpending) argue that humans evolved very intensively during this period. One famous example is the evolution of lactose tolerance, that is, ability to digest milk.
另一方面，农业大概出现在距今10000年前，400多代可不是一个小数目，进化所带来的改变不可小觑。一些人类学家（包括同样参加了学科融通研讨会的Honry Harponding）认为，人类在农业时代经历了急剧的进化改变。最著名的例子就是我们进化出了对乳糖的耐受性——即消化奶类的能力。
Michael Rose develops a more subtle and sophisticated argument, which is explained at length in his
55 theses-a New Context for Health. There is a sophisticated mathematical model underlying his argument, but the basic logic of it is actually quite simple.
Michael Rose 发展了更加精致灵巧的论证，并在他的网站（55theses.org，副标题“健康新语境”）上做出了详尽的解析。虽然他的论证建立在一个复杂的数学模型之上，但基本逻辑其实十分简单。
We think of people having ‘traits,’ but actually we change quite dramatically as we age. The key ‘trick’ is to realize that people have a suite of traits, and they can be quite different, depending on what stage in life we are talking about.
我们常说人们具有某某“性状”（traits），但其实，随着年龄增长，我们的特性会发生巨大改变。理解这种变化的‘诀窍’在于意识到，性状是一个系列，随年龄变化可能大为不同，取决于所谈论的年龄阶段。
As an extreme example, consider reproductive ability, something of great interest to evolution. Humans do not reproduce until they reach a fairly advanced age of maturation (puberty). Young adults are not very good mothers or fathers, but they improve with age during their twenties. After that reproductive ability declines and eventually disappears. So reproductive ability is actually a trait that varies quite a lot with age.
一个极端的例子就是生育力，这也是物种进化的一大重点。人类在没有达到足够成熟的青春期之前,是不会繁衍后代的。年轻人并不能马上成为优秀的父亲或母亲，但在他们二十多岁的时候，随着年龄增长，情况就有所改善。这个时期过后，生育力就开始慢慢下降直至完全消失。因此生育力就是一个会随年龄而不断改变的性状。
Another example is hair color. One man can have red hair and another blond hair. However, this will be true only while they are relatively young. Older men become grey, and many become bald. So by the time our two men turned 60, they may have the same hair color (grey), or no hair at all (bald).
另一个例子是发色。有人是红发，有人是棕发，但一般只会在相对年轻的时候才体现出这种差异。年老后他们的头发会逐渐变得灰白，许多人还会秃顶。因此当发色不同的两人在60岁后，头发就变成了一样的颜色（灰白），或者都没有头发（秃头）。
By the way, it is likely that the reason is not simple ‘degradation,’ reduced function due to aging, but that greyness and baldness evolved to signal maturity and wisdom. To really describe the phenotype of an individual we need to specify at what age it is expressed.
另外值得一提的是，这种变化的理由，也许不是年龄增长带来的简单功能“退化”，而是人类进化出了灰白头发和秃顶，作为显示其成熟和睿智的信号。因此要准确表述一个人类个体的性状，我们必须先分析这个性状在哪个年龄段被表达。
Ability to digest certain foods can also be age-dependent. I have already mentioned the ability to digest lactose, the sugar present in milk. Before we domesticated animals such as cows and sheep, only very young humans had this ability. Natural selection turned this ability off in adults because they never needed it (and it would be wasteful to continue producing the enzyme lactase that aids in the digestion of milk sugar).
对特定食物的消化能力也可能随年龄而变化。例如上文曾提到过人类消化乳糖（奶类中存在的糖分）的能力。在我们驯化诸如牛羊等动物之前，只有非常年幼的人类能够消化乳糖。自然选择使得成年人类丧失了这种能力，因为他们根本不需要（持续分泌乳糖分解酶来帮助消化乳糖，对身体机能来说也是浪费）。
Now clearly traits expressed at different ages are not completely independent of each other. An ability to digest milk sugar as an adult depends on the presence of an enzyme that evolved in order for babies to digest their mother’s milk. So traits at different ages can be correlated, either positively, or negatively. An example of negative correlation is the reproductive ability – in many animals, putting a lot of effort in reproducing early reduces the reproductive ability later in life.
很明显，性状虽然在不同年龄段各有表达，但不会毫无联系。成年人乳糖消化能力取决于一种酶的存在，这种酶是为了消化母亲的乳汁而在婴儿身上进化出来的。这意味着不同年龄段的性状可能互相关联，它们既可能正相关，也可能负相关。一个负相关的例子就是生育力——许多动物早年投入过多精力在繁衍后代上，会导致晚年生育力的下降。
So the sophisticated mathematical framework for dealing with age-dependent traits has to take into account all kinds of possible correlations, both between the same trait at different ages and between different traits. For example, most individuals have dark eye and dark hair color, or light eye and light hair color, with dark/light and light/dark combinations a relative rarity.
因此，为了研究与年龄有关的性状，精致的数学模型必须考虑到所有可能的相关性，包括同一性状在不同年龄段之间的相关性，以及不同性状之间的相关性。例如，大多数人，要么是深色瞳孔深色头发，要么是浅色瞳孔浅色头发。而深色瞳孔搭配浅色头发，浅色瞳孔搭配深色头发，这样的组合相对罕见。
We can now get to the crux of the matter. Because abilities to do something at the age of 10, 30, 50, etc. are separate (even if correlated) traits, they evolve relatively independently of each other. When grains became a large part of the diet, the ability of children to digest them (and detoxify the chemical compounds plants put into seeds to protect them against predators such as us) became critical.
现在，我们可以着手讨论我们的重点了。由于我们在10岁，20岁以及50岁的各项能力被年龄隔开（哪怕它们是相关联的），因此它们的进化也是相对独立的。当谷物在我们饮食结构中占了很大比例时，儿童消化这些谷物以及分解其中有毒化合物的能力（植物为了从人类这样的掠食者手中保护种子而将这些有毒物置于其中）变得十分重要。
If you don’t have genes to help you deal with this new diet, you don’t survive to adulthood and don’t leave descendants. In other words, evolution worked very hard to adapt the young to the new diet.
如果你没有可以帮助你应付这种新型食谱的基因，那么你就很难存活到成年，也就不会留下后代。换句话说，进化会异常努力地让年轻一辈去适应新的食物类型。
On the other hand, the intensity of selection on the old (e.g., 55 years old) was much less – in large part, because most people did not live to the age of 55 until very recently. Additionally, once an animal gets past its reproductive age, the evolution largely ceases to have an effect (in humans, presence of older individuals was somewhat important for the survival of their genes in their children and grandchildren, so evolution did not entirely cease, but was greatly slowed down).
而另一方面，对于多数年人（例如55岁）来说，自然选择的强度是很弱的，因为近代之前的大多数人类都活不到55岁。此外，一旦动物过了生育年龄之后，进化就几乎不再起效了。（对于人类来说，老人的存在对他们的基因在子孙后代中的延续是有重要意义的，因此进化并不会完全停止，但仍会大幅降速。）
What this means is that evolution caused rapid proliferation of genes that enabled children and young adults to easily digest novel foods and detoxify whatever harmful substances were in them. Genes and gene combinations that did the same for older people also increased, but at a much, much slower rate.
换言之，进化促进了帮助婴幼儿和年轻人消化新食物和分解其中毒素的那些基因快速增殖。而对老人产生同样效果那些基因和基因组合，尽管也在增加，但是增长速度却要慢得多。
This may sound puzzling – if we have the detoxifying genes that work for young adults, why shouldn’t they work for older adults? The reason is that one gene-one action model is wrong; it’s not how our bodies work. Most functions are regulated not by a single gene, but by whole networks of them.
听起来这有点令人不解——如果我们身上有解毒基因，为什么对年轻人有效，却对年长者无效呢？这是因为那种认为一个基因对应一种性状的模型是错误的，我们的身体机制并非如此运转。大部分身体机能并不是由单一基因、而是由整个基因组的互相协作来调控的。
As we age, some genes come on, and others go off, and the network changes, often in very subtle and nonlinear ways. That’s why we need the ‘trick’ with which I started, to consider functions at different ages as separate traits.
随着年龄增长，有些基因开始生效，有些则慢慢失效，协调机制也以敏感非线性的方式不断改变。我前文提到的“诀窍”，就是把思考转向被年龄隔开的性状的作用机制。
During the last 10,000 years evolution worked very hard to optimize the gene network operating during earlier ages to deal with novel foods. But the gene network during later ages was under much less selection to become optimized in this way.
过去一万年来的人类进化，尽其所能地优化了那些帮助年轻人消化新食物的基因网络。但是中老年阶段，这组基因网络就很少通过自然选择得以如此优化。
The striking conclusion from this argument is that older people, even those coming from populations that have practiced agriculture for millennia, may suffer adverse health effects from the agricultural diet, despite having no problems when they were younger.
从以上论述中我们会得出一个令人惊讶的结论：老年人，即使是那些生活在有数千年农业生活之中的老年人，还是可能遭受农业时代的食谱所带来的负面健康效果，即使他们年轻的时候适应良好。
The immediate corollary is that one thing they can do to improve their health is to shift to something known as the ‘Paleolithic diet,’ or paleo diet, for short. In the simplest form, this means eliminating from your diet any cereals (wheat, rice, etc), legumes such as beans and peas, and any dairy products (e.g., cheese).
一个直接的推论是，这些老年人可以通过转向“旧石器时代式饮食”（或者简称旧石器食谱）来改善健康。最简单的形式就是，将饮食中所有的谷物（小麦，大米等）去除，同样要减掉的还有豆类（例如各类豆子和豌豆），以及各种乳制品（如奶酪等）。
It is striking that this is almost precisely the opposite of the popular Mediterranean diet, which emphasizes wheat products (bread, pasta), cheese, and legumes (as in the Italian bean soup, in pasta fagioli, and in hummus).
读者可能惊讶地发现，这种饮食方式和流行的地中海式饮食几乎完全相反，后者强调要多吃小麦制品（面包以及意大利面），奶酪以及豆类食物（诸如意式豆汤，意面豆汤和鹰嘴豆泥里的豆类等）。
We are now getting to something I have a personal (rather than a scientific) interest in. I am about to turn 55, and although I am generally in good health, various worrying indicators – cholesterol, sugar – have been inexorably inching up.
现在讲一些涉及我的个人兴趣（而非科学方面的）的事情。我快55岁了，虽然身体大致健康，但类似胆固醇和血糖水平等各种令人担忧的指标却在一路缓慢上升。
A couple of years ago I read Ray Kurzweil Fantastic Voyage, but I was unpersuaded by his prescriptions to better health and longevity. Kurzweil’s prescription is, at basis, a calorie-restricted diet. Like the great majority of human beings, I find it extremely difficult to starve myself.
几年前，我读了Ray Kurzweil的《奇幻之旅》，但是并不认同他针对健康和长寿提出的方法。Kurzweil提出的方法，简单说，可以归结为一种控制卡路里的饮食方法。和大多数人一样，控制饮食、保持饥饿，对我来说简直难如登天。
More generally, his approach to human health and longevity is that of an engineer – you turn that dial down, another one up, and get the result you want (according to his book, he spends one day a week connected to a machine that removes bad things from his blood and adds good things).
总体上说，他改善健康和延长寿命的方式就如一个工程师所做的那样，将身体某个指标调低，又调高另一个指标，通过这样的调节来达到理想效果。（据他书中所述，他每周都会花一天的时间通过某台仪器来去除他血液中的不良物质，然后再添加有益物质。）
I am very doubtful that such an approach will work on an evolved system with multiple nonlinear feedbacks, which is the human body. So changing one variable (e.g., reducing the cholesterol level in the blood) may have unintended – and usually negative – consequences elsewhere (perhaps increasing the risk of cancer).
我实在难以相信这种方法能在人体这个高度进化的多重非线性反馈调节系统中发挥作用。改变身体的某一变量（例如降低血液中的胆固醇水平）可能会在别处引起意料之外的——通常是负面的——后果（也许会提高患癌的风险）。
To conclude, the paleo diet is the first diet, of the ones I heard of, that has a sound evolutionary basis going for it. This was a deciding factor in persuading me to try it out, which I did, starting about two weeks ago. It apparently takes about six months to see its full effects, so stay tuned for progress reports.
May 17, 2012
结论是，旧石器食谱是我所听说过的第一个有着坚实进化理论基础的食谱。这一点是我决定尝试它的决定性因素，并且两周前我开始了实践。据说大概要经过六个月的时间才能看到它的整体效果，所以敬请期待我的后续汇报。
2012年5月17日
（编辑：辉格@whigzhou）
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