戴维·赖希——为什么青铜时代是人类进化的一个转折点

从数据中可以看出，移民的影响非常大。

One thing you can see in the data is the migration impact is huge.

比如，看看今天英国白人认知能力的表现，像智力测试的分数，再对比古代人群的预测值，欧洲狩猎采集者的得分比现代平均水平低了整整三个标准差。

So for example, if you look at the trajectory for, you know, measures of cognitive performance like, scores on intelligence test in white British people today, but you look at the predictor of that in people in ancient times, the estimate for the hunter gatherers of Europe is, like, three standard deviations below the modern mean.

没错。

Right.

这差距实在太大了。

So that's hugely different.

是的。

Yeah.

从狩猎采集者到农民，分数一下子跳到了平均水平，这正是移民带来的变化。

And then you see a huge jump from them to the hunter to the farmers who are, like, at the mean, at zero, and that's migration.

对。

Yeah.

你看到的是，这两个群体在这些特质上的基准水平原本就不同。

So what you're seeing is those two groups had different set points for those traits.

对。

Yeah.

而步径存储列表的设定值则更低。

And then the step path store list have a lower set value of this.

是的。

Mhmm.

因此，你看到这个特质的预测指标在历史上波动巨大。

And so you see huge fluctuations in the predictor of this trait over time.

这并不能证明是自然选择的结果。

That doesn't prove selection.

这仅仅说明了迁移的影响。

What that is just telling you is migration.

但我们的检测方法想揭示的是：除了这些由迁移引起的波动之外，是否还存在一种持续的自然选择效应，让这个特质在不同时期、不同地区都朝同一个方向变化？

But what our test is telling you is, in addition to those fluctuations due to select, due to migration, is there a consistent effect of natural selection blowing the trait in the same direction over all over all places at times?

而这正是我们所发现的。

And that's what we're detecting.

是的。

Yeah.

有个人提出了集体智慧假说，认为人类智力的选择方向其实恰恰相反。

So there's this, a person who has a theory of collective intelligence hypothesis, which is this idea that, the selection for intelligence has actually been in the opposite direction.

随着社会的发展，分工变得越来越细。

That as society has developed, there's been more specialization.

分工越细，每个人只需要掌握世界中越来越小的一部分知识。

If there's more specialization, each person only needs to understand a smaller and smaller part of the world.

所以，古人其实比我们聪明得多，而我们反而在智力上退化了。

And, therefore, actually, the ancients were much smarter than us, and we've sort of evolved out in intelligence.

但你的研究结果却指向了相反的方向：尽管过去两千年里，随着社会越来越复杂，自然选择似乎没有明显作用，但在社会刚起步的时候，对今天能预测智力的那些能力需求反而更高。

And your results seem to point in the opposite direction that although there's not been election in the last two thousand years as, you know, society has gotten more complicated, at least when society began, there was more need for the kind of thing that predicts intelligence today.

这让人意外，因为如果你想想狩猎采集者——比如读了你同事约瑟夫·亨里奇的书，就会发现他们需要记住和判断的信息量有多大：从怎么处理食物，到怎么搭棚子、生火，等等——相比之下，我只需要会摆麦克风、提问题就行。

And the reason that's surprising is if you think about hunter gatherers, yeah, reading your colleague, Joseph Hendrick's book, the amount of information that they needed to hold onto and assess everything from, how to process food, to how to build shelters, fire, etcetera, compared to my world where I gotta, like, know how to set up mics and ask questions.

这让人觉得，祖先所面对的智力挑战，应该远远超过我们现在。

It's just like it seems like the demands on intelligence should have been, like, way higher in the ancestral environment.

所以，文明初期反而加强了对智力的选择，这真的很让人意外？

And so it's very surprising that the beginnings of civilization increase the, the selection on intelligence?

没错。

Right.

这就是数据的力量。

So, you know, this is the power of data.

对吧？

Right?

如果你去问乔，让他在这些研究之前预测一下狩猎采集者在智力这个特质上的选择压力，他大概不会给出很明确的判断，但他可能会说，按理说，这些人要处理的食物、搭建庇护所、生火等等，要掌握的信息这么多，智力水平应该挺高的。

Like, you know, the I think, Joe, if you asked him, prior to this work, what the hunter gatherer selection would be and where their set point for, you know, this particular trait would have been, you know, I think he probably wouldn't have made a very strong prediction, but he would have said, well, maybe you would have expected it to have a high predicted value of this trait because these people were really having to do a lot of things and figure a lot of stuff out maybe.

而一旦社会变得更复杂，集体智慧发挥作用，智力这个特质反而可能被削弱。

And that maybe once you have more complex societies, there'll be more of a collective brain, and maybe there'll be selection against this trait.

但实际情况恰恰在某些方面是相反的。

And in in fact, it's sort of the opposite in some ways.

所以说，数据真的很有说服力。

So it's the power of data.

这跟你想的完全不一样。

It's not what you expect.

看了这些数据之后，你才会真正体会到数据的价值——它能帮我们理清这些复杂的问题。

And, you know, after looking at this data, it's actually the value of data to try to make sense of all these things.

说实话，这真的很有趣。

You know, it's very interesting.

比如智力的基因预测指标，里面有很多让人困惑的地方。

Like, the genetic predictor of intelligence, there's lots of kind of things that are confusing about it.

所以这确实值得好好聊聊。

So it's actually worth talking about it.

还有受教育年限的基因预测指标，它和智力高度相关，而且测量得更准确。

Or the genetic predictor of years of schooling, which is highly correlated to it and is measured even better.

如果你看受教育年限的基因预测，2017年有一项来自冰岛团队的惊人研究，他们分析了过去一百年冰岛人的这一指标。

So if you look at the genetic predictor of years of schooling, there's another amazing study from 2017 from a group in Iceland, that looked at this measure over the last hundred years in Iceland.

他们对比了年长者和年轻一代，也就是近年来在冰岛出生的人。

And it looked at older people and it looked at younger people, people born more recently in Iceland.

仅仅一个世纪内，冰岛人群的智力遗传预测值就下降了约零点一个标准差，这么短的时间内出现这么大的变化，简直惊人。

And there's an estimated point one standard deviation decrease in genetic predictor of intelligence in Iceland just within one century, is an absolutely huge effect over a short period.

这其实是对受教育年限的一种自然选择压力。

And this is selection against years of schooling.

我刚才说智力，其实不是这个意思。

If I said intelligence, didn't mean to.

真正被选择的是与受教育年限相关的遗传指标。

It's selection against, the numb genetic predictors of numbers of years of school.

所以，对这个现象的一种可能解释——虽然有点笼统——是，我们实际测量的并不是对受教育年限或真实智力的选择，而是另一个与两者都相关的特质。

And so one possible interpretation of this, sort of hand wavy, is that actually what's being measured here is not selection for years of schooling or for actually real intelligence, but for another trait altogether that's correlated to both of them.

比如，受教育年限的遗传预测值，和女性首次生育的年龄高度相关。

For example, the predictor of numbers of years of schooling is very, very strongly correlated to the age at which women have their first kid.

一旦你把生育年龄这个因素控制住，受教育年限的遗传信号就完全消失了。

And if you control for that for numbers of years of schooling, all of the signal of, years of schooling goes away.

所以，我们真正测到的，可能是女性决定何时生育的倾向。

So maybe what you're measuring is women's decision about when to have children.

如果你早点生孩子，上学的时间就会少一些。

And, you know, if you have children earlier, you don't go to school as much.

如果你晚点生孩子，上学的时间就会更长。

If you have children later, you go to school more.

这可能反映的是一种延迟满足、拖延或者规划的能力。

Maybe it's some kind of measurement of delaying gratification or putting things off or planning.

同样的特质还和体重指数、肥胖，甚至走路速度有关。

The same trait is correlated to body mass index, to obesity, or to, walking pace.

这真的是我们通常理解的智力吗？还是说，这只是过去某个时代下表现出来的另一种特质？

So is this really, like, intelligence as we think about it, or is it something else that manifests itself differently in different times, in the past?

是的。

Yeah.

明白了。

Okay.

显然，在过去，上学年限本身并没什么特别的意义。

So, obviously, a trait like years of schooling was not itself a meaningful thing in the past.

而背后这些因素似乎经历了强烈的选择压力。

And the underlying things for it seem to have been under strong selections.

基因里能预测受教育年限的那些东西，显然也受到了强烈选择。

Whatever in the genome predicts years of schooling seems to have been under strong selection.

那我们该怎么理解这一点呢？

And how how should we think about this?

到底是什么在基因层面发生了变化？

What like, what is the actual thing that's changing in the genome?

是的。

Yeah.

我觉得有两点你需要考虑。

Well, I think that there's two things going on that you need to think about.

一方面，受教育年限在基因上和很多其他特质都有关联。

So One of them is that years of schooling is connected to so many other things genetically.

现在，关于受教育年限的基因预测指标，已经在数百万人群中被研究过了。

If you look at the genetic predictor of years of schooling, this trait has been measured in millions of people now.

它实际上和很多出人意料的事情有关联。

It's actually correlated to really, really surprising things.

比如女性初次生育的年龄。

It's correlated to the age at which women have their first kid.

还和人们的肥胖程度有关。

It's correlated to people's obesity.

也和人们的走路速度有关。

It's correlated to people's walking pace.

还和家庭财富有关。

It's correlated to people's household wealth.

甚至和许多看似完全不相关的其他特征都有联系。

It's correlated to a variety of other traits that seem quite different from it.

如果你以为自己测的是智力、学习年限，或者勤奋程度这类东西，那可得再想想了，因为它关联的因素太多了。

So if you think you're actually measuring years of, genetic prediction of intelligence or years of or or actual, you know, studiousness or something like that, you should think again because there's many things that it's correlated to.

似乎存在某种更普遍的特质，也许是执行功能，或者是延迟满足的倾向，也可能只是我随便说说——但这种特质正在被自然选择塑造，推动所有这些特征朝同一个方向发展。

There seems to be some kind of general trait that maybe you could think of as executive function or maybe propensity to defer gratification or something, or I may just waving my hands that is under selection, and it pushes all these traits in the same direction, one way or the other.

在过去不同的时期，这种特质可能是有利的，也可能是不利的。

And in different times in the past, it's it's it's advantageous or disadvantageous.

但当我们发现教育年限这个信号——也就是人们受教育时间更长的遗传倾向，在今天的英国白人身上表现出来时，我们简直不敢相信。

But when we found this signal of, years of schooling, being increased, the the genetic propensity to go to school for more years, as it manifests itself in people, in white British people today, when we found the signal, we were sort of incredulous.

这怎么可能呢？

Like, how could this be?

会不会是哪里出错了？

Maybe this is a problem.

所以我们做了一些检验，想确认这到底是不是真的。

So we did a few tests to try to figure out whether this was real.

其中一项检验是，我们找了一项研究，那项研究测量的不是欧洲人的教育年限，而是中国境内中国人的教育年限。

And one of the tests we did is we looked for a study where this measurement of the numbers of years of school was done not in Europeans but was done in Chinese people in China.

我们分析了那些影响中国人群教育年限的基因变异，看看它们是否与过去一万年间欧洲人群相同基因变异的演化趋势有关联。

And we looked at variants that had the effect size of many variants as they affected the number of years of school in China, and we saw whether they had a relationship, a correlation, to the trajectory of those same genetic variants in Europeans over the last ten thousand years.

这两个地区的人群，长期以来基本上完全没有任何交流。

So these are two parts of the world where the populations have been essentially completely disconnected.

欧洲人过去一万年里的这种变化趋势，不可能只是偶然跟今天中国人的受教育年限有关。

And there's no way by chance that the trajectory in Europeans over the last ten thousand years will have anything to do with the number of years, the effect on the years of schooling in China today.

但实际上，两者之间存在巨大的统计相关性，相关程度高达五到六个标准差，也就是中国当前受教育年限的效应大小，和欧洲人群的演化轨迹之间高度相关。

But there's actually a huge statistical correlation, a five or six standard deviation correlation between the effect size of variance, a number of years of school in China today, and the trajectory in Europe.

这种相关性甚至和欧洲人自身遗传变异对受教育年限的影响强度几乎一样强。

Just as strong, actually, as the effect size of variance in Europeans to years of school to to the trajectory in Europeans.

我们实在想不出，这怎么可能只是巧合。

So we just could not see a way this could happen by chance.

一旦看到这一点，我们就非常确信，这确实是一个真实存在的信号，说明自然选择在过去确实倾向于推动那些今天表现为更长受教育年限的基因变化。

And once we saw that, we really felt quite convinced that this was a real signal and that really somehow there has been natural selection to increase the genetic changes that today manifest themselves as more years of school predicting more years of schooling.

明白了。

Alright.

为了确认我有没有理解错，你的意思是，你们在研究欧洲的古代DNA，发现这些DNA似乎能预测现代欧洲人的受教育年限，或者说，古代DNA里存在某种选择压力，让这些基因更倾向于让人接受更长时间的教育。

Just to make sure I understood, you're saying you're, you know, you're you're looking at this ancient DNA in Europe and you're saying, well, it seems to predict years of schooling for modern people in Europe or at least a selection on those ancient DNA that ancient DNA seems to predict more years of schooling in modern Europe.

然后你们还发现，同样的这些基因变异，也能预测中国人的受教育年限。

And then you also find well, it also predicts how the same variants predict more years of schooling for Chinese people in China.

是的

Yeah.

所以这并不是欧洲那些GWAS研究方法带来的什么奇怪偏差。

And so this is not just some weird artifact from the way these GWAS were done in Europe.

这些基因组片段似乎能稳定地预测真正导致受教育年限延长的因素，至少在今天的人群中是这样。

This seems to parts of the genome seem to robustly predict the kind of thing that actually leads to more years of schooling, at least in people today.

没错。

Correct.

Jane Street 很保密，但我了解到一个内部机制，能很好地体现他们文化中高度信任和独特的一面。

Jane Street is pretty secretive, but I did learn about one internal mechanism which illustrates how high trust and weird their culture is.

研究人员并不会被分配计算资源。

Researchers aren't given compute allocations.

相反，Jane Street 的员工会用一种叫 Hivebucks 的内部货币，实时竞拍计算资源。

Instead, Jane Streeters use an internal currency called Hivebucks to bid for compute in real time auctions.

每个人都可以随意出价 Hivebucks，但你的出价应该真实反映你想要运行的实验所值的美元金额。

Everybody can spend as many Hivebucks as they want, but your Hivebucks bid is meant to represent the real dollar value of the experiment that you want to run.

值得注意的是，在拍卖过程中，任何人都可以修改别人的出价。

Now, notably during the auction, anybody can change anybody else's bid.

拍卖结束后，人们甚至可以直接终止别人的任务。

And after the auction, people can even kill each other's jobs.

大家彼此信任，都会以公司整体利益为重来这么做。

People just trust each other to do this in a way that benefits the whole firm.

因此，Jane Street 的计算资源分配能实时反映对最高优先级任务的共识。

As a result, Jane Street's allocations reflect a near real time consensus on the highest priority uses of compute.

正如他们的机器学习工程师 Axel 所说。

As Axel, one of their ML engineers put it.

我觉得 Jane Street 的运作方式非常自下而上，有很多不同的研究员各自训练自己的模型，比如序列模型，还有各种稀奇古怪的东西。

I think Jane Street's, like, pretty bottom up in terms of we have lots of different researchers who are all training their own models, sequence models, all sorts of other weird and wonderful things.

顺便说一下，他们新签了计算资源协议，给内部经济注入了六十亿美元的‘高币’刺激。

By the way, with their new compute deal, they've just added a $6,000,000,000 high buck stimulus to their internal economy.

Jane Street 正在招聘研究员、工程师和实习生。

Jane Street is hiring researchers, engineers, and interns.

想去了解更多？请访问 janestreet.com/thorcash。

Go to janestreet.com/thorcash to learn more.

明白了。

Okay.

我们不妨退一步看，我想弄清楚的是，过去一万八千年里，我们的环境到底发生了什么变化？

So stepping back, I wanna understand I think there's this question about what what does this tell us about what actually changed in our environments, over the last eighteen thousand years?

之前我们聊过青铜时代之后发生的事。

And we talked a little about what happened after the Bronze Age.

让我有点意外的是，我们现在居然在讨论集体智能时提到这个话题。

I wanna understand it's surprising to me we're talking about this during the collective intelligence part of the conversation.

但更让我意外的是，像智力、没有精神分裂症这些特质，似乎都相当稳定地保持在良好状态。

But it's surprising to me that things like intelligence or lack of schizophrenia or so forth, things just seem kind of robustly good.

在青铜时代之前，我们远没有达到智力的极限。

We're not maxed out before the Bronze Age.

事实上，不同人群之间的差异非常大，比如欧洲的狩猎采集者，如果当时有智力测试，他们的预测得分比平均水平低了整整三个标准差。

And in fact, there were so much the diversity among different populations was so big that you have the European hunter gatherers having three standard deviations is less predicted value for, you know, what they would score an intelligence test tested if it existed.

但他们生活在真实世界里，那里智商确实很重要。

But, you know, they were existing in the real world in a place where intelligence matters.

所以，你怎么解释呢？你看人类身体，或者任何动物，进化都强烈地塑造它们去适应生存所需的功能，可唯独这个似乎至关重要的能力，在旧石器时代或中石器时代却没受到强烈选择？

And so how can it be that the this was not a you just look at the human body or any animal and just like this evolution has been acting on it so strongly to make it functional, the things it needs to do.

而且，像智力这种对狩猎采集者来说如此关键的能力，为什么在那个时期没有被强烈地筛选出来呢？

And this one thing, which seems like so relevant, especially to what human hunter gatherers needed to do, is not under doesn't seem to have been under that strong selection in the Mesolithic or Paleolithic or those eras?

我觉得这是个非常好的问题。

I think that that's a great question.

就像我们之前说过的，人类的自然选择效率非常高。

And, like, as we talked about before, the the the the human adept selection is very effective.

只要某种特质在特定环境中具有适应性，它就能在几百年甚至几千年里，把群体的平均值显著地推高或拉低。

You it can move the mean value of traits within hundreds or thousands of years in one direction or the other if that's adaptive in a particular environment.

所以你可能会想，智力难道不是在任何时代、任何地方都有好处吗？

And so you might wonder, isn't intelligence good, you know, in all contexts and places and time?

我觉得这个问题可以从好几个角度来理解。

And I think that there's a number of ways to think about that.

首先，我觉得我们是从一个极度重视这种特质的社会角度来说的，比如能考高分、参加长期教育之类的。

First of all, I think we are speaking from the point of view of a society which intensely values this particular trait, you know, ability to score well on, IQ tests or things like them or to go to school for a long time or whatever it is.

我觉得在人类历史上，像现在这样重视智力的时代是前所未有的。

And I think this is unprecedented in human history that we live in a time like this.

你要是翻翻希伯来文和基督教的《圣经》，会发现里面根本没怎么推崇智力。

Like, if you look at the, you know, Hebrew and Christian bible and you look at how much intelligence is valued, it's basically not at all.

等等。

Wait.

但《圣经》写成的时候，尤其是《旧约》，恰恰是人类智力受自然选择最强的时期。

But that when when the Bible is being written, especially the Old Testament, is exactly when selection for intelligence is the highest point Yeah.

这可能是历史上最强的了。

It's apparently ever been.

是的。

Yeah.

没错。

Exactly.

但其实，那时候看重的是力量、勇气、虔诚这些品质。

But, like, there's it's about strength or courage or religiosity or right.

那些才是当时的核心价值。

Those are the values.

对吧？

Right?

如果你读荷马史诗，或者别的宗教经典，里面根本不是讲聪明才智。

Or if you read Homer, or the other texts of other religions, it's not intelligence.

讲的是美。

It's it's beauty.

是其他一些东西。

It's, like, other other things.

所以这种极度推崇智商的价值观，显然不是过去常见的标准。

And so this value system, which has a hyper focus on, you know, you know, smarts is not obviously a trait trait value that's been common in the past.

你可能会觉得，某些群体里，比如有些地方，确实会更看重类似受教育年限这样的东西。

You might think that in certain communities like, you know, some communities are not, there might be valuation of things that are more proximate to, you know, years of schooling.

但总的来说，这种特质在人群中并不被高度重视。

But really broadly, it's not been a high value in the population.

但显然，我们讨论的并不是直接的智商测试表现，尤其是在过去。

But obviously, the the thing we're referring to is not or the thing we care about is not direct performance on IQ test, especially in the past.

我想更清楚地理解的是，这里说的‘智力’是不是一个更广泛的概念？

That I think the thing I'm trying to understand better is this is intelligence more broadly?

也许智商测试所测的这种智力，和在新环境中自己找食物、搭住所这些事并没有很强的关联。

And maybe just that IQ test intelligence is not that correlated with here is a new world environment and go figure out how to process food there and make shelter and everything else.

所有这些事，就像你的同事约瑟夫·亨里奇提到的，现代人往往低估了小群体完成这些任务有多难。

All the things which, you know, your colleagues like Joseph Hedinger talked about, like, the how modern people underestimate the difficulty of doing this kind of thing with a small band of people.

总之，我想说的是，也许这根本就不是智商测试所衡量的那种智力，所以我们在进化中没看到它被强烈筛选的迹象。

Anyways, this is to say, like, maybe that's not IQ test intelligence and that's why we don't see that strong selection effect on this thing.

但我直觉上觉得，不管价值体系如何，拥有这种能力到极致总是非常有价值的。

But I just intuitively, it seems like regardless of the value system, it just seems very valuable to, have this trait maxed out.

所以我说的这些都只是很推测性的。

So so I'm being very speculative.

是的。

Yeah.

让我举两个例子，说说我脑子里是怎么想的——当然，我并不是这方面的权威。

And let me give you two examples about how about what this about in my head, how I'm thinking about this, and not that I'm a particularly good authority on these things.

但正如我提到的，很多看似差异很大的特征，其实彼此之间高度相关。

But as I mentioned, a lot of these traits, which are quite disparate, are highly correlated to each other.

对。

Yeah.

肥胖、受教育年限、步行速度、智商测试表现、家庭财富，这些看似杂乱无章的特征，很大程度上都受一组共同的基因变异影响。

Obesity, years of schooling, walking pace, you know, performance and IQ test, household wealth, all these crazy traits all seem to be governed to a substantial extent by a shared combination of genetic variants.

我们不妨想想，这可能意味着什么。

And let's just think about what this might mean.

在过去一百年里，冰岛的人群中，这种基因组合一直在被自然选择所淘汰。

So in Iceland, in the last hundred years, there's been selection against this combination of variants.

一种可能的解释是，这其实反映了两种养育子女策略之间的权衡：要么多生孩子但投入少，要么少生孩子但投入更多。

And one possible interpretation is it's basically selection for two ways of investing in your children, having many kids and not investing a lot in them or having few kids and investing more in them.

对吧？

Right?

所以如果你选择晚生孩子，先积累更多财富和资源，然后把更多精力投入到每个孩子身上，你的生育率就会更低，孩子也会更少。

So if you invest in deferring deferring having kids but becoming you know, having more wealth, having more resources, and putting more into each kid, you're gonna have a lower fertility and you're gonna have fewer kids.

这样生育率虽然低了，但这些孩子更有可能健康成长，在社会上表现得更好。

And that's gonna result in lower fertility, but those kids might survive more and do better in society.

另一种做法就是尽可能多生孩子，但对每个孩子的投入相对少一些。

Alternatively, you can just have as many kids as you can and invest less in them.

虽然每个孩子的前景可能没那么好，但在资源丰富的环境下——比如二十世纪的冰岛——多生孩子、少投入反而更合理。

They might have individually less good outcomes, but in a time of plenty, which is potentially Iceland in this twentieth century, it might make sense to have more kids and invest less in them.

所以这里其实有个权衡：要么多生孩子、少投入，要么少生孩子、多投入，让孩子在各方面更出色，诸如此类。

And so there's a toggle between having more kids and investing less in them and having more kids and investing in less in one's life, and having fewer kids and investing more in excelling in various ways or something like this.

你可以想象，在不同时期、不同生态环境下，资源的分配方式其实各有不同。

And so you can imagine that actually at different times and in different places in in ecology, there's resource there's different ways.

比如哺乳动物通常怀孕时间长，生的孩子少，但投入很多；而鱼类一次产下成千上万的卵，大部分都会被吃掉，但在某些环境下，这反而是繁衍后代的有效策略。

Like, mammals often invest a lot in with a pregnancy and a small number of children, whereas fish will spawn huge numbers of offspring into, you know, the the the river, the great majority of whom will be eaten, but that is an effective way to produce offspring in certain conditions.

所以，根据环境条件的不同，我们会在这两种策略之间来回切换：要么生很多孩子但投入少，要么生得少但投入多。也许我们看到的，正是这种模式在不同时间和地点的反复变化。

So there'll be a toggle depending on the environmental conditions back and forth between investing in large numbers of offspring with fewer and less investment or smaller numbers of offspring with more investment, and maybe we're just seeing that move back and forth over different places and times.

同样的问题也适用于精神分裂症和双相情感障碍——这些病怎么可能会有优势呢？

Similarly, for schizophrenia and bipolar disease, how could this ever be advantageous?

但也许我们看到的这些疾病，其实是某种特质谱系的体现，而这些特质在某些情境下反而是有好处的。

But maybe what we're seeing with these diseases is a kind of readout of some kind of spectrum of traits that actually in some context might be advantageous.

比如，焦虑、富有想象力或者神经质，这些特质在萨满或重视幻觉与创造力的宗教传统里，可能反而是种优势。

Maybe being anxious or being imaginative or being neurotic might be helpful in a shamanistic tradition, you know, in a religious tradition which values people who can have visions, or values people who can be creative.

也许这些只是精神分裂症或双相障碍的亚临床表现，在某些时代有利，在另一些时代却有害。

And maybe these are subclinical versions of schizophrenia or bipolar disease that in certain times may be advantageous and in other times may be disadvantageous.

也许我们看到的，只是不同类型的创造力或思维方式在不同环境中的选择差异。

Maybe you're just seeing selection from different types of creativity or other thinking that can be valuable in different contexts.

我这话说得有点笼统，但我的感觉是，这些复杂特质之所以没有朝单一方向演化，是因为谱系的两端都有优势，这些特质的影响是多维度的。

I'm waving my hands here, but my sense is that these complex traits have not pushed in one direction because there's advantage there are spectrums where there's advantages to both ends of the spectrum, and there's multidimensional, you know, impacts of these different traits.

朱利安·詹姆斯有个关于意识起源的著名理论，叫‘二分心智’，我这解释得不太准确。

Julian James has this famous theory in the origins of consciousness in the bicameral mind that I'm butchering this.

但依我理解，早在荷马之前，所有人都可以说是患有精神分裂的，因为他们真真切切地相信神明是真实存在、可以与之对话的人。

But fundamentally, the way I understand it is that up until Homer, basically, everybody was schizophrenic in the sense that people people genuinely thought that gods or whatever were real people that you're communicating with.

他的观点是，古代文献里的人确实表现出这种行为。

And his claim is that ancient texts seem to show people behaving in this way.

或者说

Or

你被要求去相信那些幻象。

You're being asked to believe in visions.

是的。

Yeah.

没错。

Exactly.

你知道的，

You know?

即使在今天，我觉得在一些宗教群体里，依然很看重与上帝沟通、看见异象、经历超自然体验这些事。

And even today, I think, you know, there's valuation in some religious communities and, you know, communicating with God and having visions and having supernatural communions.

是的。

Yeah.

所以我也不确定。

And so, I just don't know.

是的。

Yeah.

但我觉得特别有意思的是，去思考为什么某些特质并不总是有利的。

But I think it's super interesting to imagine to to to ask the question why certain traits are not always advantageous.

对于精神分裂症和双相情感障碍来说，大多数基因突变确实是有害的。

For schizophrenia and bipolar disease, there is a sense in which most of the mutations are disadvantageous.

从变异模式就能看出来，那些风险因素的变异通常频率很低，而且影响也都很小。

We can see that from the patterns of variation where the variants that are risk factors tend to be low frequency, and they tend to be small effects.

另一个受到自然选择影响的特征是，人体脂肪含量在下降，没错。

So another trait you find under selection is, the trend away from body fat Yes.

从农业革命以来就是这样。

Since the agricultural revolution.

为什么会这样？

Why is that?

你看到的是，导致肥胖和体重指数风险的基因突变组合在减少。

So this is, what you see is a reduction in the combination of genetic mutations that make you at risk for obesity, body mass index.

同样地，这和体脂率更高、腰臀比更高、二型糖尿病风险更高也高度相关。

And similarly and very correlated to it, higher fat mass, higher waist to hip ratio, higher type two diabetes risk.

在过去一万年里，这一地区的人群中，这些特征的变异平均下降了一个标准差，大约减少了1万人的患病风险。

And so there is clear selection by about a standard deviation on the scale of modern variation for these traits reducing about 10,000 over the last ten thousand years, in this part of the world.

那这背后可能是什么原因呢？

So what can be going on there?

为什么以前没有对这种特征组合施加选择压力？

Why was there not selection for this combination of traits before?

有一个长期存在的理论，叫作‘节俭基因假说’。

There's a long standing idea known as the thrifty genes hypothesis.

这个理论认为，当狩猎采集人群进入农业社会、食物变得充足之后，就不像以前那样需要大量储存脂肪来应对饥荒了，因为食物供应变得更稳定了。

The idea is that, that once you have hunter gatherer populations that move into a farming environment where there's plentiful food, there is no longer a need, to the same extent to be able to build up body fat to sort of survive in times of stress because there's more constant stores of food.

因此，一旦进入农业社会和食物充裕的时期，身体脂肪就会受到自然选择的淘汰。

And so as a result, there will be no, there will be natural selection against body fat, which can be, once you move into an agricultural environment and to periods of food plenty.

所以你看到的可能是，过去一万年里，欧洲和中东的这群人逐渐进入了食物更稳定的时代，囤积脂肪的优势减弱了，这种特征组合因此被逐渐淘汰。

And so maybe what you're seeing is that this group of people in Europe and The Middle East over the last ten thousand years has moved into a a period of relatively more stable food where building up stores of fat are not as advantageous, and there's been selection against this combination of traits.

实际上，欧洲人在基因上对二型糖尿病的抵抗力比世界上一些其他人群更强，比如非裔美国人和美洲原住民，他们接触农业的时间可能没那么长。

Europeans actually are relatively better protected genetically against type two diabetes than some other populations around the world, like African Americans and native Americans that have perhaps not been as exposed to agriculture for as much time.

所以你看到的，可能是长期稳定食物供应带来的影响。

So you may be seeing the effect of more exposure to more stable food accessibility.

这还从另一个角度反驳了常见的说法。

This is also another way in which the data goes against a common story.

常见的说法是，狩猎采集者其实饮食更稳定，因为他们吃的种类更多样。

And the common story is that hunter gatherers actually had much more stable diets because they were more buried.

他们并不依赖某一种谷物或作物来获取热量。

And so they weren't reliant on a single cereal or a single crop for their calories.

如果一种猎物消失了，他们还能去找别的食物。

And if, you know, if one game went away, they had other things that they could scout for.

他们能更灵活地迁徙，因为不用被土地束缚。

They could move locations more easily because they weren't tied down to the land.

所以他们的食物供应其实更稳定。

And so they were more food stable.

但事实上，如果身体储存脂肪的倾向被自然选择淘汰了，那就说明农业社会的饥荒虽然频繁，但整体食物供应至少比狩猎采集者更稳定。

But in fact, if there's been selection against storage of body fat, that suggests that as, as unstable and as common as famines might have been in agricultural societies, it's at least more stable than what the hunter gatherers had.

我觉得这里有个时间尺度的问题。

I think there's a timescale issue.

你说得对。

You're absolutely right.

依我理解，我不是人类学家，

So I think, as I understand, and I'm no anthropologist.

没错。

No.

但我知道，在一些传统狩猎社群里，人们一旦捕到猎物，往往会大吃一顿，迅速囤积脂肪，然后连续好几天不吃肉，直到下一次狩猎开始。

But my understanding is that when there's a hunt in some of these, in in in traditional societies or communities that hunt, people will often gorge themselves and eat a huge amount and build up a sort of temporary store of fat and then go with multiple days without eating meat sometimes until the next hunt.

所以，狩猎采集者会经历营养供应的大幅波动，而农耕社会就没这么明显。

And so there is this sort of boom bust, access to high value nutrition, that is not true to the same extent in farming communities.

另一方面，这些长期饥荒在农业社会中更常见，但发生频率和节奏跟狩猎的周期完全不同。

On the flip side of this, these long these famines are, I think, something that occurs more commonly in agricultural societies, but the timescale and the tempo of them is very different from the hunting tempo.

也许每三年就会遭遇一次饥荒。

So maybe there's a famine every three years.

事实上，如果你查看一些农耕族群的骨骼，会发现更多压力痕迹，可能就是因为每三年或每五年就来一次饥荒。

And indeed, if you look at the bones of farmers, at least in some communities, there's more stress in them, maybe due to a famine every three years or a famine every five years.

但自然选择未必会针对这三年的周期起作用。

But selection might not be acting on that three year time period.

你上次打猎后储存的脂肪，根本撑不到三年后下一次饥荒。

Your fat store, from, you know, the latest hunt is not gonna carry you through to the famine three years later.

所以，熬过饥荒和为几周后的食物短缺囤脂肪，完全是两回事。

And so survival of famines is a different thing than building up body fat for, being able to, survive two weeks later.

我有个突然想到的问题，你刚才提到过‘看’……

A kind of random question I have is if you were mentioning look.

相比之下，其他那些对生存和自然环境更重要的因素——比如免疫系统，尤其是青铜时代以后——它们的影响远超过智力。

As compared to these other things, which matter much more for fitness and these natural environment, the immune system, especially after the Bronze Age, all these other things have mattered more than intelligence.

所以这些因素承受的选择压力远大于智力。

And so they've been under much more selective pressure than intelligence.

没错。

Right.

这让人不禁想，智力的上限是不是还有很大的提升空间？

That makes you wonder whether there's much more room at the top for intelligence.

也就是说，如果人类在进化过程中更侧重于智力，我们本可以变得更聪明。

As in if humans had been selected, especially for intelligence, they could have been much smarter.

这一点之所以重要，是因为我们现在正在开发人工智能，目标就是尽可能提升它的智能水平。

And the reason that's relevant is we're currently building AI systems, which are trying to make it as smart as possible.

事实上，训练过程的唯一目标就是智能。

And in fact, the only goal of the training process is intelligence.

我们不需要同时担心如何增强它们的免疫系统，而且

We don't have to worry about also at the same time making their immune systems powerful And

我们有充足的精力去投入这件事。

We have lots of energy to spend on it.

对吧？

Right?

同时还要确保它们不会患上精神分裂症。

And at the same time making sure they're not schizophrenic.

我想我们确实得考虑这个问题。

I guess we kinda have to worry about that.

但如果在过去十万、二十万甚至一百万年里，智力并不是人类演化中的主导特征。

But, if intelligence has not been the dominant trait under selection for humans over the last ten, twenty, hundred thousand years.

那是不是意味着，智力还有很大的提升空间？

Does that mean that there's more room at the top for this trait?

我觉得这些特征中，很多都有很大的提升空间。

I think there's more room at the top for a lot of these traits.

是的。

Yeah.

我觉得身高这种特征，完全可以比现在极端得多，往一个方向大幅改变。

I think that you can move height very extremely in one direction much more than it is today.

其他这些特征也一样，都能被推得比现在极端得多。

You can move any of these traits very much more extreme in the other traits.

这么做很可能带来很严重的负面后果。

There's probably very strong negatives to doing that.

你很可能得牺牲掉其他一些东西。

You're probably sacrificing other things.

我觉得这里面肯定存在权衡。

And I think that there's trade offs probably.

但我觉得，如果自然选择真的把其中任何一个特征往更极端的方向推，平均值肯定会发生移动。

But, I think it's highly likely that if natural selection was pushed pushed any of these traits, in, more in one direction than it is, the mean would move.

所以，自从人类走出非洲以来，所有这些进化都是在调整当初那批人本来就有的基因变异——就是我们上次聊到的，大约一万人左右的群体，从非洲扩散出来。

So all of this, evolution since out of Africa is acting on alleles that already existed in the pool of human variants from that first group, which we were talking about last time on the order of 10,000 people that, you know, exploded out of, out of Africa.

你觉得奇怪吗？就那么一小群人，居然藏着如此丰富的潜在变异，能支撑起从认知模式、抗病能力到身高等各种特征的多样化演化？

And it's a is it surprising that across all these different traits from cognitive profiles to, resistance to different kinds of diseases to, height to whatever that that one pool of people contained so much latent variation that they could supply the, you know, enough, you know, stretchiness to accommodate all these different traits that you're studying now?

这是个很有深度的问题。

That's a rich question.

我认为，对于人类这种复杂性状，种群内的变异量非常巨大。

And I think that the human population has with complex traits, a tremendous amount of variation.

在人类群体中，影响身高的变异因素非常多。

So, within the human population, there's a huge amount of variation that affects height.

影响体重指数的变异也同样非常丰富。

There's a huge amount of variation that affects body mass index.

如果你把所有这些基因突变都调整到促进长高的版本，一个人会变得极其高大，简直像摩天大楼一样。

If you take all these mutations and all set them to the high height variant, a person will be extremely tall, like as tall as a tall building.

是的。

Yeah.

当然，这种情况实际上不可能发生。

You know, if you of course, which will never happen.

但如果你把所有影响精神分裂症风险的基因变异都朝同一个方向调整，那就会导致风险极高，或者几乎完全免疫。

But if you take all these variants that affect schizophrenia risk, they will and you point them all in the same direction, there will be extreme risk or extreme protection, for schizophrenia.

对于复杂性状来说，它们由许多突变共同影响，人群中早已存在足够的变异，足以让种群快速适应当前环境的最佳状态。

So for complex traits, one's underpinned by many mutations, all the variation already exists to move the population to a different adaptive set point that's optimal in the environment which it's in.

所以，如果一个种群被带到一个新环境中，几百甚至几千年之内，它就能迅速调整到新的适应点。

So if you push the in a population into a new environment within hundreds or thousands of years, the population can rapidly move to a new adaptive set point.

有些特殊性状，比如消化牛奶的能力，或者对镰状细胞贫血的抵抗力，需要一个非常关键的突变，而这个突变在人群中可能还不存在。

There are some unusual traits like ability to digest cow's milk or protection against sickle cell anemia that require a single very important mutation that may not yet exist in the population.

这时候，你只能等某个个体偶然发生这个突变。

And then you have to wait for the mutation to occur in some people.

当种群规模比较小，比如只有上万人的时候，你可能得等几十代甚至几百代，这个突变才会出现。

And when the populations are relatively small, only 10,000 people, you might have to wait dozens or hundreds of generations for that mutation to arise.

但当种群规模足够大时，突变就不再受限了。

But when the populations are large, there's not mutation limiting anymore.

所有可能发生的突变，都会有人发生。

Every mutation that can occur does occur.

世界上有八十亿人。

There's 8,000,000,000 people in the world.

每一代大约会产生三十个新的突变。

There are maybe 30 new mutations every generation.

所以这相当于什么呢？

So that's like, what is it?

每一代大约有两千四百亿个新的点突变。

It's like two forty billion new point mutations every generation.

人类基因组只有三十亿个DNA碱基。

There's only 3,000,000,000 DNA bases in the genome.

所以每个可能的突变，每代都会发生大约一百次，我们再也不受突变数量的限制了。

So every mutation that can occur does occur about a 100 times every generation, and we're not mutation limited anymore.

所以不需要担心突变会不会再次出现。

And so it's not like you have to that the mutations can arise again.

它们确实会反复出现。

They do arise again.

但当人口只有不到一万人时，有时得等几十代甚至上百代，新的突变才会出现。

But when the population's only 10,000, you have to wait dozens or hundreds of generations sometimes for the new mutation to occur.

所以，青铜时代发生的变化，会不会只是因为人类人口规模足够大了？

And so how likely is it that the thing that changes with the Bronze Age is just that the human population was big enough?

在公元前3000年左右，全球人口大概有五千万人左右。

So you in 3,000 BC, you go to, I think, population of 50,000,000 ish people.

人口足够多，而且不同地区之间的基因交流也足够频繁，以至于那些选择压力不强、单靠进化原本很难显现的性状，终于能被自然选择捕捉到了。

The population is big enough that and the gene flow between different areas is high enough such that things which don't have an overwhelming selection coefficient, which aren't overwhelming if they were by evolution, are finally visible, visible to selection.

我觉得这不太可能是真的，但这个想法确实非常有意思。

I think that's not likely to be true, but it's extremely interesting thing to think about.

我觉得，只要人口规模达到百万级别，任何可能发生的突变，几代之内就会全部出现。

So I think already when population sizes are on the order of a million so or so, every mutation that can occur does occur within a few generations.

所以，就算只看欧洲的人口，也早在青铜时代之前就已经达到这个水平了，其他地区也差不多，或许刚好是青铜时代或农业革命初期才达到的。

And so that's well before the Bronze Age if you take the population even of a place like Europe, but also also of of of other places, or maybe it's the dawn of the Bronze Age or the farming period.

所以你提出的问题其实是：当人口规模还很小的时候，自然选择可能根本没法有效发挥作用。

So the the question you ask is maybe when the population is small, natural selection doesn't work effectively.

对。

Yeah.

人们通常认为，在小群体中，自然选择的效果会变差，这确实没错。

So a common thing that people think about with natural selection, and that is true, is that in small populations, selection doesn't work effectively.

因为在小群体里，突变的频率会因为随机性而在代际间大幅波动。

And that's because mutations bop around in frequency from generation to generation a lot in a small population just randomly.

比如一个一千人的群体，每代突变频率的波动幅度大约是千分之一。

So if you have a population of size 1,000, populations mutations will bop around by a frequency of one over a thousand every generation.

如果选择系数小于这个数值，它就会被遗传漂变带来的随机波动完全淹没。

And if the selection coefficient is less than that, it will be drowned in the random bopping around of frequencies due to genetic drift.

但这是针对一千人的群体而言的，1%的选择系数其实已经很强了。

But that is already for a population of 1000.1% selection coefficient is very weak.

我们说的是一百分之一的效果，这在进化上算是非常强的了。

We're talking about 1% effects, and that's much very strong.

即使在一千或一万人口的群体中，这种选择也能很好地发挥作用。

It will work very well even in a population of a size a thousand or 10,000.

如果某种突变只在大群体中才会开始上升，而在小群体中不会，那它的选择系数大概只有万分之一或十万分之一，这种突变要花上一万到十万代才能显著增加频率，也就是几十万年甚至上百万年。

If you are talking about mutations of the type that will start rising in some only in large populations but not small populations, those are selection coefficients that are on the scale of one over 10,000 or one over a 100,000, and those ones will take 10,000 or a 100,000 generations to rise in frequency, which is hundreds of thousands or millions of years.

所以在咱们讨论的这个时间尺度上，这根本起不了作用。

So that's not gonna do anything over the time scale we're talking about.

这纯粹是个时间长短的问题。

There's just a time scale issue.

我明白了。

I understand.

所以这项研究中，我们讨论的是百分之零点五及以上、可测量的较强选择系数，这些在小群体或大群体中都能起作用。

So we're talking about strong measurable selection coefficients on the order of half a percent or more in this study, and all of those are gonna work in small populations or large populations.

它不会受群体规模的影响。

It's not gonna be affected by the population size.

有意思。

Interesting.

但你的意思是，一般来说，只要群体规模达到某个阈值，决定性因素就是时间长短，而不是群体大小。

But you're saying more generally, once you hit a given threshold of population, the dominant factor is time span, not population size.

没错。

Correct.

明白了。

Okay.

挺有意思的。

Interesting.

确实非常有意思。

It's very interesting.

但这一点其实很多人并不了解。

And it's actually not widely understood.

是的。

Yeah.

好的。

Okay.

说到和以往假设相矛盾的数据，你之前发给我的那篇马利克2016年的论文发现，五万年前的现代人和古人类之间并没有固定的差异。

So speaking of data contradicting what you might have otherwise assumed, One of the papers you sent me beforehand, Malik 2016, found that there are not fixed differences between modern and archaic humans fifty thousand years ago.

而我们知道，这正是所谓的认知革命发生、现代性开始出现、人们开始创作艺术的时期。

And, of course, we know this is the period in which the so called cognitive revolution happened and modernity started and people are making art or whatever.

这是否意味着，现代人之所以成为现代人，并不是因为生物学上的变化，而是某种文化上的转变？

Does this suggest that nothing biological changed to make modern humans modern and some the thing that happened was some cultural change.

我们该怎么理解这些数据所传达的信息？

How how do we understand what this data tells us?

没错。

Right.

大约五万年前，或者更早一些，从十万年前到五万年前这段时间，文化的演变速度明显加快了。

Fifty thousand years ago or so or maybe hundred hundred thousand to fifty thousand years ago, there's a quickening of the pace of change in culture.

比如，人们开始大量创作具象艺术，制作串珠项链，在岩壁上绘画等等，同时工具的创新速度也迅速提升。

So people you see the first extensive rep representational art and like bead necklaces and drawings on the wall and so on and so forth, and also a rapid increasing pace of innovation, the types of tools that people use.

所以有人会想，是不是发生过某种基因上的‘开关’，也就是人群中出现了一次重要的基因突变，迅速扩散到几乎所有人身上，从而让人有能力做这些事——比如某些基因让人类具备了复杂的语言能力。

And so the thought might be that there was gonna be have been some kind of genetic switch, a kind of, important genetic change that, was occurred in the population and that swept to high frequency that everybody suddenly had, soon had, and that made it possible for do these thing to do these things, maybe some genes that allowed people to have rep complex language, representational language, for example.

2016年，我和同事们在这篇论文里做了一件事：我们在全基因组范围内寻找可能符合这种特征的区域，也就是今天几乎所有人类都共享的、可能源自十万到二十万年前的共同祖先的基因片段。

And so one thing that we did in 2016 in this paper by and colleagues, is we looked across the DNA for places that might be expected to look like this, that where all people living today or nearly all people living today share a common ancestor, maybe a 100,000 or 200,000 years ago.

我们仔细排查了所有能分析的DNA序列，但除了四五百个年代早于五十万年前的片段外，根本找不到任何更近期的共同祖先痕迹。

And we looked really hard and right across all the DNA we could look at, we couldn't find anything more than four or 500 more recent than four or 500,000 years ago.

这个结果简直让人震惊，因为看起来在这一时期，没有任何关键的自然选择事件影响了今天所有人类的共同祖先。

This is like a crazy result because, it looks like there's no key selective sweeps that have occurred in this period that is ancestral to everyone living today.

我们之前谈过欧洲人和东亚人之间没有明显的自然选择事件，但就连这一关键时期——物质文化大量涌现的时期——所有人类共有的祖先群体里，也找不到任何类似的自然选择痕迹。

We talked before about no selective sweeps between Europeans and East Asians, but there don't even seem to be any selective sweeps between like, shared between all humans in this really important period when a lot of, evidence in the material culture record appears.

所以，也许这一时期确实存在生物学上的适应，但它是多基因共同作用的结果。

And so it could be that there's biological adaptation in this period, but it's polygenic.

有大量基因突变同时朝同一个方向变化，帮助整个群体逐渐达到一个新的平衡点，但并没有某个关键的生物学变化在这一时期迅速普及开来。

There's lots of mutations that all shift in the same direction to help the population to move to a new set point, but there's no key biological change that rises to high frequency in this time.

那么，五万年前的这群人，是所有走出非洲的人的祖先，也包括一些非洲人吗？

And this group, fifty thousand years ago, they are the ancestors of everybody out of Africa or also some Africans?

这个时间点是在十万到五万年前。

So this is a 100 to 50,000 years ago.

这一群体是西非人、大部分东非人，以及所有非非洲人群的共同祖先。

And, this is the population that's ancestral to West Africans, to most East Africans, to all non Africans.

不过，非洲内部有少数群体，他们的基因中还保留了更多古老分支的血统。

And there's a couple of populations in Africa that have substantial ancestry that comes from more divergent groups.

比如，南非的科伊桑人，或者中非雨林地区的狩猎采集者，他们的基因里有相当一部分来自大约二十万年前就与其他人类分支分道扬镳的群体。

For example, Khoisan, from Southern Africa or Central African rainforest hunter gatherers have substantial fractions of their ancestry from groups that diverged maybe two hundred thousand years ago from the other lineages.

但今天这些群体的人照样能上大学，做别人能做的所有事情。

But all of these groups today are able to do go to college, do everything everybody else does.

所以，并没有证据表明，某些群体缺少了其他群体都有的关键基因突变。

And so there is, like, no evidence that there is any key mutation lacking in some groups that are not present in the others.

所以我们现在看到的不同人群之间的差异，尤其是考虑到五万到十万年前，那个群体的人口规模非常小。

So the the differences we see between different groups of people, especially if this group of people, 50 to a 100,000 people years ago, had a very small population size.

我记得上次我们聊过，大概就一万人左右。

I think last time we were discussing on the order of 10,000 people.

对。

Yeah.

也就是说，世界上所有人，或者几乎所有人今天所展现的多样性，其实都早已潜藏在那个小群体里了——这大概也是你想表达的意思：如果你把基因组里各种不同的变化叠加起来，累积效应会非常显著。

So basically, everybody in the world or almost everybody in the world or the variance we see between different humans today was latent in this group and which is it was sort of seems, and I guess your point to that, well, if you just stack up different different things across the genome, then stacking them up really has a big effect.

但有意思的是，如今世界上有这么多不同的族群，而所有这些多样性居然都源自一个极小的人口。

But that it's interesting that, like, have so many different groups in the world today and that all that diversity comes from a very small population.

我觉得在人类遗传学领域，很多人都认为，我们这个群体本身就蕴含了塑造几乎所有性状的潜力。

I think a lot of us in human genetics think that the, our population contains within it the clay that's needed to make almost any trait.

对。

Mhmm.

而根据不同的环境或选择压力，这些性状的平均值会朝不同方向变化。

And that depending on environmental conditions or selection conditions, the mean value of these traits will move in different directions.

这其实是个实证问题：过去不同人类群体经历了多少自然选择？

There's an empirical question, a real question about how much selection there's been, in different human populations over time.

我们参与的这项新研究显示，至少在过去一万八千年、一万年、五千年来，在这个地区，某些重要性状确实发生了显著变化。

One of the things this new work that we're involved in is doing is showing that at least in the last eighteen thousand years, ten thousand years, five thousand years in this part of the world, there actually has been significant movement, at least for a handful of important traits.

我们研究了五百多种性状。

We looked at more than 500 traits.

其中大约一百种复杂性状，在这段时间里呈现出系统性的明显变化。

About a 100 of them, complex traits showed significant movement in a systematic direction, over this time period.

所以看来，人类对所处环境的适应确实发生了，并且可能比以往任何时期都更强烈。

So it really does seem that there is a response, to the environments people are living in that has occurred over this period and is potentially stronger than in previous periods.

Crusoe 的机器学习基础设施团队特别厉害，总能想出巧妙的办法，把硬件性能压到极致。

Crusoe has an amazing ML infra team that keeps finding clever ways to squeeze more performance out of their hardware.

比如，分词现在成了智能工作负载的一大瓶颈。

For example, tokenization has become a real bottleneck for argentic workloads.

智能提示通常特别长。

Argentic prompts are often extremely long.

它们的 KV 缓存占用率很高，导致 GPU 的预填充任务被严重压缩。

They tend to have high kvcache rate rates, which shrinks the GPU's prefill work.

这样一来，传统上必须顺序执行的分词步骤，在生成第一个词之前的耗时占比就变得更大了。

This means that the tokenization step, which is traditionally sequential, is a much larger fraction of time to first token.

为了解决这个问题，Crusoe 开发了 FastTokens，一个开源的 Rust 分词器，通过并行处理来充分利用现代 CPU 的所有核心。

To solve this, Crusoe built FastTokens, an open source Rust based tokenizer which paralyzes things in order to take advantage of all the cores on modern CPUs.

Crusoe 在这里得动点脑筋，因为直接照搬常规方法根本行不通。

Crusoe had to get creative here because a naive approach doesn't work.

比如预分词阶段，你不能简单地把文本切成几段然后跑正则表达式，那样一旦单词正好被切在分界线上，就会出问题。

For example, for pre tokenization, you can't just split your text into chunks and run regex because you'd end up with issues whenever a word straddled the split.

Crusoe 的解决方案是给每个线程分配一个专属区域，并允许它读取自身边界外额外的一千字节。

Crusoe solved this by giving each thread an authority zone, plus the ability to read one kilobyte past its own edges.

这一千字节的缓冲区能确保不会误切词元，而专属区域则能避免重复处理。

This one kilobyte buffer guarantees that you won't misprocess a token, and the authority zone guarantees that you won't end up with duplicates.

完全不需要线程间的协调。

No cross thread coordination required.

Crusoe 把这个优化和其他几项巧妙的调整结合起来，让真实生产环境中的首词延迟提升了高达百分之四十。

Crusoe combined this optimization with a handful of other smart tweaks in order to get up to 40% faster time to first token on real production workloads.

想了解更多，请访问 crusoe.ai/thorcache。

To learn more, go to crusoe.ai/thorcache.

我们之前聊过，五万年前的人类和今天的人类在生理上并没有本质区别。

We were talking earlier how there's no fixed differences between humans fifty thousand years ago and humans today.

对。

Mhmm.

既然人类在基因上没有发生足以支撑符号表达、农业等重大变革的改变，我上次问过你这个问题，但结合现在的背景，为什么冰河时代之前没有出现农业？

So if there's no genetic basis for, the kind of thing that allowed humans to have more symbolic representation, have farming, etcetera, I I asked you this question last time we talked, but especially with this context, why no farming before the Ice Age?

从基因上讲，我们早就具备了。

Genetically, we're there.

这个问题真有意思。

Such an interesting question.

没错。

Right.

从基因上讲，我们早就具备了。

Genetically, we're there.

五万年前，人类的共同祖先已经具备了农业所需的一切条件。

The common ancestral population has all of the ingredients for farming fifty thousand years ago.

这些人当时已经分散到世界各地——美洲大约一万五千年前，新几内亚四万年前，东亚、欧洲、西非，也都到了。

And, you know, these people are distributed into different parts of the world, The Americas, you know, fifteen thousand years ago or whatever it is, you know, New Guinea, forty thousand years ago, East Asia, you know, Europe, you know, West Africa.

可直到一万两千年前，农业才开始出现。

No farming develops, before, you know, twelve or eleven thousand years ago.

农业只在最近这一万两千年，也就是全新世——冰河时代结束后的时期——才真正发展起来。

It only develops in the last, you know, 12,000, the period known as the Holocene, which is sort of the end of the ice age.

如果你去问气候科学家和考古学家，我每次遇到这方面的专家都会问这个问题。

And if you talk to climate scientists, and archaeologists, you know, I keep asking people this question every time I meet someone who's an expert in this.

你怎么解释，为什么农业会在这么多地方同时出现？

It's like, how can this be that farming develops in all these places?

我们真的生活在一个如此特殊的时代吗？

Are we really living in such an unusual time?

人们告诉我，确实如此，在两百万年的尺度上，我们正处在一个极其不寻常的时期。

And people tell me, indeed, we're living in an un very unusual time on a scale of two million years.

大约一万两千年前，我们进入了这样一个时期——不仅温暖，而且气候极其稳定。

That is twelve thousand years ago, we switched into this period of not just warmth, but climate stability.

这听起来确实有点难以置信，但我们正生活在一个如此特别的时代。

That and that actually this is true and sort of hard to believe that we're living in special such a special time.

但如果你看看湖底沉积物的数据，通过同位素信号来测量温度波动，会发现我们这个年代的年际、十年际、百年际温度变化都小得多，我们恰好生活在一个相对稳定的时期，这简直是个奇迹。

But if you look at, for example, data from bottoms of ponds where you can measure the fluctuations of temperatures using isotopic signatures, apparently, we're in a period where it's just fluctuating a lot less year to year and see and ten years to ten years and hundred years to hundred years, and it's just a period of relative stability that we are miraculously living in.

而当这种相对稳定期到来时，多个群体不约而同地转向了农业，尽管他们的基因基础早在五万、十万、二十万甚至三十万年前就已经定型了。

And that when this period of relatively stability happens, you somehow it follows that multiple groups independently turn to agriculture even though the genetic complement, you know, all of whom have the same genetic complement that arises 50,000, a 100,000, 200,000, 300,000 years ago.

这个说法挺疯狂的，可大家居然都接受了，简直难以置信。

It's kind of a crazy observation that people just accept, but it's, like, unbelievable.

哦，所以你把时间范围扩大了。

Oh, so you you you increased the range there.

你刚才说的是十万年、二十万年、三十万年前。

So you said, 100,000, 200,000, 300,000 years ago.

根据现代人和三十万年前人类之间的基因差异，你认为早在三十万年前，人类就已经和现代人差不多了？

And we based on the genetic differences between modern, modern people and people from even 300,000 years ago, you think basically there's they're modern 300,000

三十万年前？

years ago?

我不确定。

I don't know.

我现在一直在想这个问题。

Like, I'm thinking about this all the time right now.

这正是我目前正在认真思考的事情。

This is actually, like, actively what I'm thinking about right now.

大约在三十万到四十万年前，人类文化发生了一次巨大转变，出现了新型技术，比如从石核上打制石器。

And, like, you know, there's a big transformation in terms of the culture of humans 300, 400,000 ago, this invention of level, technology, the ability to make stone tools out of cores.

对。

Yeah.

这被称为中石器时代革命，或者中旧石器时代革命，具体叫法要看是在非洲还是欧亚大陆。

The Middle Stone Age revolution or the Middle Paleolithic revolution, depending on whether what you call it in Africa or Eurasia.

这是一种全新的石器制作方式，尼安德特人和现代人都会，但在东亚和南亚却看不到。

And this is a revolution, a new way of making stone tools that's shared by Neanderthals and by modern humans, but is not shared in East Or South Asia.

这是一次重大变革，背后很可能伴随着认知能力的提升，才能制造出这样的工具。

And it's a big change, and it it involves a cognitive change presumably in order to make this sort of technology.

后来，大约在十万到五万年前，又出现了另一次转变，进入上旧石器时代或晚石器时代，工具制作方式再次更新，但没前一次那么剧烈。

And then there's a further change to the upper paleolithic later stone age, maybe, a 100 to 50,000 years ago, when there's the second transition where the new type of tool making, but not as revolutionary as the earlier one.

至于认知能力的飞跃究竟发生在什么时候，现在还不清楚。

So when the cognitive leap happens is unclear.

今天人类各族群的分化，比如南非的科伊桑人、热带雨林的狩猎采集者，这些谱系的分裂时间更接近三十万或二十万年前。

The diversification of the lineages leading to people living today, like Khoisan Southern Africas and rainforest hunter gatherers, and that all occurs more on the timescale of 300,000 or 200,000.

这些人都有能力上大学

And all of these people are capable of, you know, going to college

而且

and

做任何事情。

doing everything.

所以，很难说在二三十万年前，人类的工具、认知能力、行为模式和遗传天赋就还没完全具备，连尼安德特人其实都已经拥有了这些。

And so, you know, it's not obvious that all the toolkit, the cognitive toolkit, the behavioral toolkit, the genetic abilities were not all in place two or three hundred thousand years ago and that even Neanderthals had them.

对吧？

Right?

所以，这件事其实并没有表面上看起来那么确定。

So it's not obvious that this was not the case.

是的。

Yeah.

所以，我真的说不准。

And so, like, I just don't know.

你把这些人群分散到世界各地，而这种分化发生在二十万到三十万年前。

You sort of distribute these people to send it from this diversification that happens 200, 300,000 ago to different parts of the world.

然后，突然之间，就在一万两千年前，农业在不同地方接连出现。

And then, bing, you know, after twelve thousand years ago, you start having agriculture popping up in different places.

这真是个令人费解的谜团，对吧。

It's kind of an outstanding mystery Right.

在人类历史上。

Of human history.

我觉得难以置信，我们竟然生活在一个气候上极其特殊的时期，放眼两百万年都找不出第二个。

And, you know, I I find it unbelievable that we live in a play in a time period that climatologically is so unique on a scale of two million years.

但我的同事们说，这确实是事实。

But my colleagues tell me it's true.

农业在这么多不同环境中独立出现，气候因素看起来确实有点让人意外。

The climate thing seems surprising given there are so many different environments in which agriculture was independently developed.

我现在明白了，尽管环境各异，但整体的气候波动可能反而减小了。

Now I understand that across environments, the variance could have gone down.

但如果这事只在某个地方、某个时间发生过，我倒还能接受这种解释。

But just like if if it only had happened in one place at one time, I I could have bought that explanation.

可问题是，新大陆的人在种玉米，旧大陆的人在搞小麦，而且是在完全不同的环境里，这就太让人意外了。

But the fact that they're making maze in the new world and they've got, you know, serials in the old world and so forth and just in a very different environments makes it surprising that

这确实非常不可思议。

it was very, very surprising.

我们虽然接受了这个事实，但说真的，这简直是个荒谬的观察。

And I think we accept it, but it's just, like, a crazy observation

对。

Right.

大多数人都没意识到这一点。

That most normal people don't realize.

是的。

Yeah.

大家普遍认同的是，世界上几乎所有人的共同祖先，除了雨林里的狩猎采集者和科伊桑人，大约生活在七万年前。而且所有人都承认，这些人当时已经具备了推动农业革命和建立国家社会所需的所有认知、行为和智力条件。

You know, the thing that basically everybody accepts is that the common ancestral population of almost everybody in the world, except for rainforest hunter gatherers and Khoisan is like around 70,000 years And everybody accepts that these people all have in place the cognitive behavioral intellectual ingredients that are necessary for the farming revolution and state building state societies.

因为当这些人的后代分布到西非、东非、美洲、欧洲、南亚、东亚、新几内亚等地时，他们的后裔全都做了同样的事。

Because when these descendants of these people get distributed to West Africa, to East Africa, to The Americas, to Europe, to South Asia, to East Asia, to New Guinea and so on, their descendants all do this.

对。

Yeah.

在世界这些不同的地方，几乎是各自独立、半独立、完全独立，甚至明显完全独立地发生的。

Like independently or semi independently or completely independently or demonstrably completely independently in all these different parts of the world.

所以，完成这件事所需的认知能力，早就已经具备了，只是延迟了很久。

So the cognitive resources for doing this must have all been in place, but it's a very long fuse.

就像在祖先群体分裂之后，过了四万年、六万年，甚至更久，在各地才突然爆发，发展出农业和其他各种文明。

Like it delays for forty thousand years for 70, you know, sixty thousand years in all these different places after the common ancestral population splits up and then, you know, ignites into, like, agriculture and all these other things after that point.

这说法听起来有点疯狂。

It's kind of a crazy claim.

你明白吗？

Know?

你甚至还可以争论，这个延迟可能长达三十万年——从尼安德特人分化开始，或者从现代人类不同谱系分离时算起，这同样说得通。

And then you could argue about whether the actual fuse is three hundred thousand years, you know, from when Neanderthals separate and from when different lineages of extant modern humans separate, and that's also plausible.

所以我们被要求相信的这一系列事情，确实有点离谱。

So it's kind of a crazy sort of set of things that we're being asked to believe.

会不会是农业早就存在了，只是还没出现冶金技术，那种让人口在公元前5000年青铜时代开始暴增的条件？

Is it possible that agriculture existed, but you didn't have modern metallurgy or whatever it was that allowed populations to explode starting in 5,000 BC with the Bronze Age.

因为从人口角度看，公元前10000年到5000年的新石器时代早期，其实没什么大动静。

Because, like, population wise, it doesn't seem like, you know, 10,000 BC to 5,000 BC in the early Neolithic, much is happening.

也许他们确实种地了，但没用上铜。

It's just possible that they had farming, but they didn't have copper.

他们也没有锡——而锡得从中东弄来，才能大规模发展出能用青铜的文明。

They didn't have tin, which you needed to go to, I guess, the Middle East for to develop a civilization that could make use of bronze at a large scale.

所以他们就从历史记录里消失了？

And so they just disappeared from the historical record?

我觉得我们该能发现他们的考古遗迹才对。

I I think we would see their archaeology.

还有美洲那些惊人的发展，全都是在石器时代完成的。

And, like, you know, the extraordinary developments in The Americas, which are entirely Stone Age.

如果他们真的完全消失了，今天我们也应该能看到他们的痕迹。

You you would see them today if if they had gone completely vanished.

对啊。

Oh, yeah.

我的意思是，你想想，咱们真该去一趟墨西哥的特奥蒂瓦坎。

I mean, there's, like you know, you you know, we we should go for a trip to Teotihuacan in Mexico.

对啊。

Oh, yeah.

那是当然。

Course.

那地方真的特别震撼。

Of It's, like, like, so impressive.

我二十岁那年去的时候，就觉得它跟古埃及一样令人惊叹。

Like, you know, when I went there when I was 20, you know, it's just like it's totally as impressive as as ancient Egypt.

是的。

Yeah.

你知道，这规模大得惊人。

You know, it's, like, huge.

简直庞大到没边了。

It's massive.

而且完全没用金属。

It's without metal.

更让人惊叹的是，不仅没用金属，连动物和轮子都没用，这太不可思议了。

And it's, it's even more impressive because it's not only without metal, but it's without animals and without wheels, which is crazy.

这种奇迹简直让人无话可说。

Like, the the the the Marvel is just, like Right.

这么大东西，居然没用轮子就搬动了。

Hauled without wheels.

没错。

Right.

要是让那些自以为老世界更优越的人去这些地方看看，他们的这种想法就彻底没了。

Like, take any person who has, like, an old world superiority and, like, take them to these places, and they will not have it anymore.

这些地方的东西真是非同寻常。

It's just extraordinary what's in these places.

这些人群早在两万年前就与东亚人的祖先分道扬镳，四万年前就与西欧亚人的祖先分开了。

And these are people who separated 20,000 ago, at least, from the ancestors of East Asians and forty thousand years ago from the ancestors of West Eurasians

对。

Mhmm.

从那以后，他们的生物和文化工具箱其实一直没变，但这一切的发展却迟迟没有发生，中间隔了这么久。

And, you know, just had the same biological, you know, cultural shared toolkit from then, but there's just a a fuse, a long fuse delay until all this stuff happens.

真有意思。

Interesting.

这事儿太神奇了，可我们却从不追问为什么。

It's kind of like an amazing thing, and we don't question it.

你现在正在研究，或者想研究哪些关于人类历史的大问题？

What are other questions you have that, peep yeah.

你目前在探索哪些类似的人类历史宏观问题？

You're you're either are investigating right now or want to investigate these kinds of big picture questions of human history?

我觉得吧，我真的挺困惑的。

I think that I'm I mean, I'm I'm perplexed.

我不确定我们之前有没有聊过，但我一直对古人类和现代人类之间的关系感到非常迷茫。

I don't know if we talked about it before, but, like, I remain very, very confused about the relationships between archaic and modern humans.

我们现在已经有来自欧洲、西欧亚和中欧亚地区古人类的基因组序列了，比如尼安德特人。

We have genome sequences now from archaic humans who lived in Europe and the West Eurasia and Central Eurasia, the Neanderthals.

我们还获得了丹尼索瓦人的古基因序列——自从上次聊天后，我们终于有了他们的骨骼样本。

We have archaic sequences from these enigmatic Denisovans who we now have, a skeleton for, since we last talked.

现在已经有证据表明，一具头骨确实属于丹尼索瓦人。

There's now a skull from a Denisovan that's been shown to be a Denisovan.

同时，我们也掌握了大量现代人的基因数据。

And we have data from lots of modern humans.

但这些群体之间的关系，依然存在很多重大谜团。

And there's really big mysteries about the relationships amongst these groups.

从基因上看，丹尼索瓦人和尼安德特人其实是近亲。

So genetically the Denisovans and the, Neanderthals are sisters.

他们源自一个大约五十万到六十万年前的共同祖先群体。

They descend from a common ancestral population five or 600,000 years ago.

而这个群体，又是在更早的七八十万年前，从现代人类的共同祖先中分化出来的。

And that group's descends a couple 100,000 years before, seven or 800,000 years ago from the common ancestors of modern humans.

所以从全基因组数据来看，尼安德特人和丹尼索瓦人都是来自同一个远古祖先群体的古人类。

And so genetically, the whole genome data says that Neanderthals and Denisovans are archaic humans from a common ancestral archaic population.

但尼安德特人和现代人类之间有很多共同点，这些却没在东亚人群中出现。

But there are so many things shared between Neanderthals and modern humans that don't seem to be shared between with East Asians.

他们都使用中石器时代的石器技术，也就是一种独特的石器制作方式，而这种技术在东亚从未出现过。

They both share, Middle Stone Age tone stone tools, level one technology, this cognitively unique type of way of making stone tools that wasn't used in East Asia.

他们的线粒体DNA和Y染色体序列也完全相同。

They both have the same mitochondrial DNA and Y chromosome sequence.

尼安德特人的Y染色体和线粒体DNA，其实是来自现代人类的基因，是通过杂交传入的。

So the Y chromosome sequence of Neanderthals, the mitochondrial DNA of Neanderthals is actually modern human that came through interbreeding Mhmm.

大概二三十万年前传入，后来迅速扩散到几乎全部人群。

Two or three hundred thousand years ago and then shot up to a 100% frequency.

尼安德特人和现代人类都是大约二十万到三十万年前古人类与现代人类混合的产物，这一点在古代和现代DNA的变异模式中已经得到了明确证实。

And then Neanderthals and modern humans are both the product of mixture events that happened between archaic and modern humans three hundred or two hundred thousand years ago, demonstrably through patterns of variation in ancient and modern DNA.

所以，尼安德特人和现代人类之间似乎共享着一些丹尼索瓦人没有的东西，尽管全基因组数据表明丹尼索瓦人和尼安德特人关系更近。

And so it feels that there's something shared between Neanderthals and modern humans that's not shared with Denisovans even though the vote of the whole genome says that Denisovans and Neanderthals are related.

这就让人不禁怀疑，是不是有什么因素把尼安德特人和现代人类更紧密地连在一起，而和丹尼索瓦人不同，尽管从全基因组来看，丹尼索瓦人和尼安德特人确实聚在一起。

So one wonders whether there's something connecting kind of, Neanderthals and modern humans that's different from Denisovans even though genome wide Denisovans and Neanderthals cluster.

所以我现在一直在想这个问题。

So I'm thinking about that all the time now.

那这种联系会不会是由于我们没注意到的交配事件，或者他们曾经生活在同一片区域？

And then connecting them would be interbreeding events or being in the same place at the same time that we missed?

确实存在过交配事件，是的。

There's a known interbreeding event Yeah.

是从现代人类的祖先谱系流向尼安德特人的，但比例据说只有百分之五左右。

From the lineage leading to, modern humans into Neanderthals, but it's supposed to be only 5%.

对。

Yeah.

所以我对这5%很感兴趣，它其实暗示了更深远的影响。

So I'm interested in that that that 5% is actually a sign of something much more impactful.

这意味着，某种程度上，尼安德特人在某些方面其实非常‘现代’。

That is that somehow Neanderthals are in some sense deeply modern in some ways.

尽管他们被大量古老基因淹没，但他们对现代人类的影响可能比我们想象的要大得多。他们和现代人类共同拥有的中石器时代和中旧石器时代变革，本质上可能比我们以为的更贴近他们的核心身份。

And even though they get swamped by archaic genes, that somehow they actually have more of a modern impact than one would think and that the Middle Stone Age and, you know, Middle Paleolithic revolution that they share with modern humans is actually more fundamentally a part of who they are in some sense than we think.

有意思。

Interesting.

抱歉。

I sorry.

这个混血事件发生在什么时候？

When was this interbreeding event?

距今30万到20万年前。

300,000 to 200,000 ago.

所以，尼安德特人与今天大多数人类的共同祖先，可能比所有现代人类之间的共同祖先还要更近一些。

And so the common ancestor between Neanderthals and most humans alive today is potentially more recent than the common ancestor between all humans alive today.

当然了。

Oh, for sure.

对。

Yeah.

这太不可思议了。

Which is crazy.

没错。

Yeah.

其实，人类与包括丹尼索瓦人在内的所有古老人类的分化，都在现代人类的变异范围之内。

Well, you not not divergence to all the archaic humans, including Dinesovans, is within human variation.

明白了。

Okay.

等等。

So but Wait.

什么？

What?