So I could be wrong,
大家好，如果我没弄错的话，
but I think this talk may have the distinction of being the one talk in this series that ends with orgasm.
这个演讲可能是本系列里唯一以高潮作为结尾的演讲。
But let's not get ahead of ourselves.
不过请不要太猴急。
Have you ever thought about the fact that you're here, alive on this planet because every one of your ancestors reproduced?
你是否曾想过，你之所以能活在地球上，是因为自己的每个祖先都成功地繁衍出后代吗？
Every one, in an unbroken chain,
毫无例外，完全没有断裂，
all the way back to the first life on this planet, over three and a half billion years ago.
一直回溯至地球上的第一个生命为止，时间大约是三十五亿年前。
That's a lot of reproducing. And for the past billion years, your ancestors reproduced sexually.
多到数不清的世代交替。过去十亿年来，你的祖先通过有性生殖来繁衍后代。
So sex is a pretty big deal. But you probably knew that. But let's talk about human mating.
可见性爱真是件大事。不过你可能早就知道这点了。但还是让我们来谈谈人类是怎么择偶的。
Why does human mating take the forms that it does? Why are we attracted to certain people?
为什么人类会有某些特定的择偶行为？我们为什么受到某些人的吸引？
Why do we sometimes form long-term romantic relationships? Why do we sometimes cheat?
我们为什么发展长期的亲密关系？我们为什么出轨？
Now I don't mean why consciously do we do these things. I don't mean what happens in the brain to cause it.
我指的不是我们为什么有意识地做这些事。也不是我们的大脑如何引发这些行为。
I mean, why did we evolve these feelings and these behaviors?
而是我们为什么演化出这些感受和行为？
In other words, how did the underlying brain structures and brain chemistry contribute to our ancestors' reproductive success
换句话说，问题是我们祖先的大脑结构和脑部化学对传宗接代有何贡献，
so that those traits got passed on into the present generation while others didn't.
使某些行为模式得以留存到现在，而其他行为模式则在演化中消失？
Answering evolutionary questions like this is like being a crime scene investigator,
回答有关演化的问题，就像化身为侦探一样，
we're left with the evidence, and we have to try to establish what happened.
必须依据现有的线索，推论出过去发生的事。
So let's go back six or seven million years ago to our early ancestors.
让我们回到六、七百万年前，也就是我们的远祖生活的年代。
This is right after the split between our lineage and the lineage that would eventually give rise to chimpanzees.
当时人类的祖先刚与黑猩猩的祖先分道扬镳不久。
Now these were small brained apes, they walked on two legs,
他们是一群有着小脑容量，并以双足行走的人猿，
and males probably fought each other for mating opportunities.
公人猿可能会为了交配机会而大打出手。
We know this because males fight for mates in all of our closest living relatives, chimpanzees, orangutans, gorillas.
我们知道这点，因为在人类现存的近亲中，如黑猩猩、长毛猩猩和大猩猩等雄性，都会为了争夺异性而打架。
And because males are larger than females when they fight for mates.
在雄性必须为了争夺异性而打斗的物种中，雄性的体型通常都大于雌性。
And the fossil record indicates that our male ancestors were larger than females.
化石纪录也显示，公人猿的体型的确大于母人猿。
So males tend to be larger, more muscular, stronger, more physically aggressive, when they fight for mates.
所以，雄性通常体型较大，肌肉比较发达和强壮，争夺交配机会时也比较暴力。
Our species has all the hallmarks of a species that's experienced an evolutionary history of male fighting for mates.
人类也具有这些行为特性，我们的演化史显示，男人会为了争夺交配机会而打斗。
For example, men have, on average, 60 percent more muscle mass, and 75 percent more upper body muscle mass,
比如说，男人的全身肌肉质量和上半身肌肉质量，平均而言分别比女人多出60%和75%，
and those differences in musculature translate into large sex differences in strength.
肌肉质量上的差异也反应在两性力气的明显差距上。
The average man is stronger than 99.9% of women.
普通男性比99.9%的女性更强壮。
These are data on hand strength, which is a good predictor of overall upper body strength, on over 600 men and women.
手掌握力能准确预测上半身力量，这些数据显示超过600位男女的手掌握力。
And as you can see, there's a large sex difference.
如各位所见，两性的差距相当明显。
And in fact, not one of almost 400 women had as strong of a hand strength as the average man.
事实上，将近400位女性里没有任何一位的手掌握力大于普通男性。
So, men can open jars.
所以男人才打得开罐子。
And move furniture or at least two things that we're good for.
以及搬家具，男人至少有这两个专长。
Who cares, right? The answer is that men care.
谁在乎呢，对吧？答案是男人在乎。
Men, especially young men, seem really concerned about figuring out who's the toughest or strongest, or the most physically formidable,
男性，尤其是年轻男性，似乎特别在意谁最威武不屈，强壮有力或勇猛剽悍，
and sometimes they devise elaborate ways for determining this.
偶尔还会用甚为复杂的方法一较高下。
From early development, boys and men are more physically aggressive than girls and women all over the world,
从早期发展开始，男孩就比女孩更具侵略性，举世皆然，
and this aggression sometimes results in violence.
这种侵略性有时会导致暴力。
Men have a virtual monopoly on same-sex homicides.
男人几乎独占所有的同性谋杀案件。
In other words, men are vastly more likely to kill each other than women are to kill each other.
换句话说，男人杀害同性的占比远远超过女人杀害同性的占比。
These are data from every society from every time period in history for which data were available when the authors compiled them,
这是我们所能取得的跨时代跨社会的历史数据显示出，
on proportion of same-sex homicides that are male killing male.
男性犯下同性谋杀案的占比。
And as you can see, the percentage is always close to 100%.
如各位所见，比例几乎达到100%。
On average, 95% of same-sex homicides are committed by males,
平均有95%的同性谋杀案都是男性犯下的，
and importantly, these don't include war killings, which would bring the percentages even closer to 100%.
更重要的是，这并未计入战争，计入战争后，男性谋杀同性的占比将更接近100%。
And from what evidence that we have, a dominance among men translates into mating and reproductive opportunities.
从现有证据看来，在男性群体中取得强势地位能增加择偶和交配机会。
So we're a species that's experienced an evolutionary history in which our male ancestors won mating opportunities through the use or threat of force.
演化史显示人类的男性远祖往往借着武力获得交配机会。
In that regard, our apple has not fallen far from the evolutionary tree.
从这个面向来说，我们离人类演化的结果并不远。
But in other ways, human mating and reproduction are profoundly different from what we see in our close relatives,
但从其他方面而言，人类的择偶和交配行为不但和我们的近亲大相径庭，
and they've changed a lot since our early ancestors.
也和我们的先祖相距甚远。
For example, males in chimpanzees, orangutans and gorillas, spend time and effort competing for mates,
比如说，雄性的黑猩猩、长毛猩猩和大猩猩会耗费时间和精力争夺异性，
but don't spend much time with individual females and don't provide resources.
却不会将心力投注在个别异性上，也不会为其提供资源。
They don't provide food for their offspring. So that's a big change.
它们不会找东西给小猩猩吃。这是个很大的不同。
Although most human societies allow polygamous marriage, that is one man married to more than one woman,
虽然人类社会多半允许一夫多妻，男性可以跟多名女性结婚，
even within polygamous societies, most marriages are monogamous.
但就算在这种社会中，大多数婚姻仍是一夫一妻。
And in the average hunter-gatherer society, almost 80% of married women are monogamous, so that's different.
而在一般渔猎社会中，几乎有80%的已婚女性采取一夫一妻，所以这一点是不同的。
And, importantly, men provide resources for their mates and offspring. So how did we get there?
更重要的是，男性会提供资源给伴侣和小孩。我们为什么演化出这种行为？
Well, in species where males fight each other for mates,
在雄性必须通过打斗争夺异性的物种里，
dominant males indicated by the larger, darker male symbols here,
强势的雄性，这里用较大的深色男性符号代表，
tend to have more mating opportunities, and hence more offspring.
倾向于拥有较多交配机会和后代。
And subordinate males tend to have fewer mating opportunities and are more likely to fail to reproduce.
而弱势雄性的交配机会则较少，也较难成功繁衍后代。
So this sets up an interesting situation, because for subordinate males,
对处于这种情况的弱势雄性来说，
it would be advantageous to attempt monogamy rather than winning lots of mating opportunities.
比较有利的作法是采取一夫一妻，而非尝试取得许多交配机会。
One mate is better than none.
有个伴总比没有伴来得好。
The problem is that in general, subordinate males cannot defend females from dominant males,
问题在于一般而言，弱势雄性无法保护伴侣免于强势雄性的染指，
and besides, females tend to prefer mating with dominant males for the genetic benefits, producing stronger, healthier offspring.
此外，雌性也倾向于偏好与强势雄性交配以便取得优秀基因，生育更强壮和健康的后代。
So what changed all of this was probably several transitions happening together around the same time.
人类之所以有所不同，可能是由于某些同时发生的改变。
By about two and a half million years ago, we had started to incorporate more meat into our diet.
两百五十万年前，人类的饮食开始纳入肉类。
We know this from various lines of evidence, including -- this is cool
我们从不同证据得知这点，包括
stone tool cut marks on animal bones dated to 2.5 million years ago.
动物骨头上的石器痕迹，这些痕迹可以回溯至二百五十万年前。
That's cool. I love this stuff!
我超喜欢这些东西！
And then by about 2 million years ago, brain size really started to increase,
两百万年前人类的大脑容量也开始大幅增加，
and with that came a lengthening of the juvenile period,
随之而来的是为时更久的幼儿期，
so now kids became both really costly and costly for a long period of time.
养儿育女变得更耗费资源，也更耗费时间。
And this made male provisioning both possible and necessary.
这些变化都使雄性提供资源的行为成为可能和必要。
Possible because it's much easier to bring back calories, protein, fats, in the form of meat than trying to do that by transporting plant foods,
之所以可能，因为以肉的形式带回卡路里、蛋白质和脂肪要比通过运输植物性食物容易得多，
and necessary because kids became so energetically costly
之所以必要，是因为养儿育女变得更耗费资源，
that individual females would have had trouble providing resources for themselves and their offspring.
使得女性无法独立提供自己和儿女所需的资源。
And when we look at modern hunter-gatherer societies, that's what we see.
这也正是我们在现代渔猎社会所见到的情形。
These are aggregate data across several hunter-gatherer societies on net daily calories.
这是好几个渔猎社会的每日热量综合统计数据。
Are you bringing in more calories than you consume, through foraging, or are you consuming more than you bring in?
经由采集取得的食物所生产的热量，比消耗掉的热量来得更多，或是更少？
And the green bars are net daily caloric surplus, in other words, bringing in more than you consume.
绿柱代表剩余，亦即每天生产的热量多于消耗掉的热量。
And the red bars are a deficit, so you're consuming more than you bring in.
红柱代表不足，亦即每天生产的热量少于消耗掉的热量。
And you'll notice that men from about 20 years of age to 60 years of age are operating at a daily caloric surplus.
各位可以看到，二十岁至六十岁的男性每日的热量生产状况呈现剩余。
They bring in, generally through hunting, more calories than they can consume, and these calories are distributed.
他们从狩猎活动中产出剩余的热量并将之分配出去。
If it's large game, it's generally distributed equally to everybody in the village or camp.
如果捕获大型猎物，通常会均分给部落或营地中的所有人。
Smaller items can be brought back to individual family,
比较小的猎物则可带回给自己家人，
but this contrasts with what's going on with women, in their reproductive years, they're operating at a daily caloric deficit.
相对来说，女性在生育期间的热量生产状况则呈现不足。
Gestation, lactation, carrying babies, are extremely costly energetically and limit one's ability to forage efficiently.
怀孕、泌乳、照顾婴儿是极度耗费能量的事，限制了女性采集食物的效率。
So male provisioning, both possible through hunting, and necessary.
男性从狩猎中取得食物的行为于是变得可能且必要。
And this change had profound impacts on human mating and reproduction.
这个变化对人类的择偶和生殖模式带来了深刻的影响。

In a sense, it tipped the balance for females.
在某个意义上，它也改变了女性的择偶行为。
So now it was sometimes worth mating with a subordinate male,
从此以后，与弱势男性交配不一定不利，
even if he may not possess the best genes, if he provided resources. And this is baboon pornography.
即使这些男性的基因并非上等，他们或许也能提供资源。这是狒狒的色情杂志。
I probably should have warned you there'd be monkey porn. This is from PlayBaboon Magazine.
抱歉，我或许该早点提醒各位会看到猴子色情图片。这张是狒狒玩伴杂志的内页。
Alright, I'm going to stop with the jokes.
笑话就说到这里。
This is a female baboon in estrus, so her genitals are swollen, and this happens in a lot of primate species.
这只母狒狒正处于发情期，它的外生殖器变得肿大，很多灵长类都会这样。
Females' appearance changes over the cycle,
雌性的外观会随着生理变化周期而变化，
and becomes more attractive and this incites male competition for females during the fertile part of the cycle,
在发情期变得更具吸引力，这会引发雄性之间的竞争，当雌性进入排卵期时，
with dominant males tending to monopolize copulations, closer to ovulation.
强势的雄性会试图独占所有交配机会，越接近排卵期越是如此。
Well. We don't look like this. And you knew that.
但人类不像这样。这点你早就知道了。
But what you might not know is that women's attractiveness does change over the cycle.
但你或许不知道的是女人的吸引力也会随着生理变化周期而改变。
My lab, and others, have shown that women's faces, voices, even odors,
我的实验室和其他研究者都发现，女人的脸孔、声音甚至气味，
are more attractive to men during the fertile part of the cycle.
在排卵期时会更具吸引力。
But these changes are extremely subtle.
但这些变化非常难以察觉。
And compared to other primates, the evidence indicates that we've evolved to suppress cues to ovulation.
相较于其他灵长类，我们已演化出隐匿排卵线索的本领。
That in a sense, ovulation is concealed in humans.
换言之，人类将排卵期隐藏起来了。
But think about what impact this would have.
想想看这会带来哪些影响。
This would mean that dominant males would not be able to monopolize copulations near ovulation.
这代表强势男性无法在女性进入排卵期时独占所有交配机会。
It would protect the pair bond from invasion by a dominant male.
伴侣之间的关系也得到保护，不至于受到强势男性的破坏。
So that a male in a pair would have more confidence that he was the father of the offspring.
而弱势男性也更能确定自己的确是小孩的亲生父亲。
The couple is having sex throughout the cycle.
人类伴侣在整个生理变化周期都能做爱。
And this is unique to human mating, we don't see it in many other primates.
这是人类的特殊行为，在许多灵长类身上都见不到。
We have sex throughout the cycle.
我们在整个女性生理变化周期中都能做爱。
And so this would essentially increase a male's confidence in paternity,
这可以增加男性对其后代亲缘关系的信心，
because a dominant or some other male wouldn't be able to target the female and bully their way in at the fertile point in the cycle.
因为其他男性无法在他的伴侣进入排卵期时强行介入。
And this would have important implications for parental investment,
这对亲代投资带来重要影响，
in particular, males providing resources for their offspring.
尤其对会为后代提供资源的男性来说更是如此。
Because across species, when males provide resources for offspring,
因为不论什么物种，如果雄性会提供资源给后代，
they target those resources toward their own biological offspring,
它们只将资源投注在自己亲生的后代，
and they avoid investing in the offspring of unrelated males.
而避免将资源浪费在陌生雄性的后代。
And so the evolution of male care for offspring and investing in resources and offspring, pair bonding,
所以，男性的育儿行为，亲代投资、伴侣关系
and concealed ovulation, went very much hand-in-hand over our evolution.
和隐匿排卵等行为特征，都在我们的演化史中环环相扣。
We have also evolved a specialized psychology for forming long-term romantic relationships with the possibility of investing in offspring together.
我们也演化出特别的心理机制，用来发展长期亲密关系，以便合力养儿育女。
We fall in love.
我们坠入爱河。
All around the world, people prefer mates who are kind and generous and capable and willing to care for mates and offspring.
全世界的人都喜欢心地善良、大方慷慨、能力出众且愿意照顾伴侣和小孩的人。
In one of the largest cross-cultural studies of human mate preferences ever conducted, covering 33 countries shown in red here,
一个有史以来规模最大、横跨33个国家，也就是以红色标出的部分有关人类择偶偏好的研究显示，
the single most important mate choice criterion to both men and women, was mutual love and attraction.
不论男女，都认为最重要的择偶条件就是相互的爱意和吸引力。
But as you also know, people are not always perfectly faithful to their mates.
但正如你也知道，人们并不完全忠于自己的伴侣。
And in particular, women sometimes face a tradeoff between good genes and investment.
进一步来说，女性偶尔得面临优秀基因和充足资源之间的取舍。
Women sometimes find themselves in relationships with men who may be caring providers,
有时候女性会与善于提供资源的男性发展关系，
but may not possess the best quality genes for offspring making them strong and healthy.
但这些男性的基因或许并不优秀，无法生育最强壮和健康的后代。
And several features of women's mating psychology seem to have evolved, in part, to resolve this trade off.
女性的许多择偶心理机制似乎正是为了解决这种难题而演化出来的。
And I mean, recruiting genes, if you will, from outside of the long-term relationship.
我指的是在长期亲密关系外寻求更优秀的基因。
For example, women have more sexual fantasies about men other than their long-term partner, during the fertile part of the cycle,
比如说，女性在排卵期时，较常对其他男性有性幻想，而较少幻想自己的长期伴侣，
and that's particularly true if the long-term partner has physical signs of being lower in genetic quality,
尤其是当长期伴侣的生理表征显示出其基因较不优秀，
like he's less physically attractive. I think that's interesting.
例如外表体态不具吸引力等。我觉得这很有意思。
That's why I'm talking about it, I hope you do too.
这正是为什么我要讨论这点，希望各位也这么觉得。
And women's mate preferences similarly change over the cycle
女性的择偶偏好也会随着生理周期变化而变化，
so that they prefer more dominant, more masculine males during the fertile part of the cycle.
女性在排卵期时比较偏好阳刚的男性。
These are results of a study that I conducted on women's preferences for men's voices.
这是我的一个研究结果，主题是女性对男性声音的偏好。
And I used computer software to manipulate recordings of men's voices
我用计算机软件操纵男性的声音，
to make them sound either more masculine or more dominant, or more subordinate, more feminine.
好让这些声音变得阳刚而强势，或顺服而柔弱。
And I had women rate them on how attractive would this man be for a short-term, purely sexual relationship, and for a long-term committed relationship?
然后请女性受试者回答，这些男性作为短期性爱对象和长期亲密对象的吸引力各自为何？
And I also got information about where women were in their cycles.
我同时也询问女性受试者正处于生理变化周期的什么阶段。
Were they in the fertile or non-fertile part of the cycle?
是否处于排卵期或非排卵期？
These were all women not taking hormonal contraception.
这是未使用荷尔蒙避孕法的女性受试者的资料。
And what I found was that women preferred a more masculine, dominant-sounding voice, specifically in the fertile point of the cycle,
我发现女性，尤其是处于排卵期的女性，较为偏好阳刚而强势的声音，
and only for a sexual relationship versus a long-term committed relationship.
而且这种偏好只出现在短期性爱对象上。
Now, this sounds like science fiction, but it's science, fact.
这听起来像是科幻小说，不过它其实很科学。
Because this result has been shown lots of times across a variety of domains from women's preferences for men's voices,
因为相同的结果已被证实许多次，从女性对男性声音的偏好，
that this result was replicated by another lab.
另一个实验室也得相同的结论。
Women's preferences for men's faces, bodies, odors, and even behavior.
到女性对男性脸孔、身材、气味、甚至行为的偏好等皆是如此。
Well, I said that we would get to orgasm. And we're there.
我说过我们会以高潮结束。该是时候了。
I just want to start by saying I'm for it.
我最想说的是我完全赞成高潮。
I'm pro-orgasm. I think more people should have more orgasms.
我是高潮的支持者。我觉得大家应该更常高潮。
But from a scientific perspective, women's orgasm is especially fascinating
但从科学角度而言，女性高潮特别引人入胜，
because there's evidence indicating that it increases the probability that conception will result from an act of sex.
因为证据显示它会增加性行为的受孕机会。
There's evidence that it brings sperm up through the female reproductive tract and toward the egg.
证据显示，女性高潮能将精子带往女性生殖道深处，直达卵子。
And think about what the implications here could be.
想想看这意味着什么？
If women were more likely to have orgasms with some men than others,
如果女性与某些男性做爱时较易高潮，
then this could be a mechanism by which they choose, not consciously, to be fertilized by some males and not others.
这或许会使得女性无意识地选择怀下这些男性而非其他男性的小孩。
And wouldn't you predict that women would be more likely to have orgasms with males of high genetic quality?
那么女性与拥有优秀基因的男性做爱时会不会较易达到高潮？
And in fact, a study by my lab published just a couple of years ago found that women reported more orgasms,
事实上，我的实验室几年前发表过的一个研究发现，女性达到更多高潮，
earlier timed orgasms, that is, they were easier to achieve, they achieved them more quickly,
也更容易和更快达到高潮，
when they were having sex when their mate was more masculine and more dominant,
如果她们的做爱对象较为阳刚和强势，
and what's interesting is that this was true only for their orgasms from sexual intercourse,
有趣的是，这种现象只出现在性交上，
but not from other partnered sexual behaviors.
但不出现在其他性行为中。
I'll let you use your imagination what those might be.
请发挥想象力猜猜什么是"其他性行为"。
So we've seen that thinking like an evolutionist can enable us to predict things about ourselves that we did not already know,
从演化论观点来思考，能引导我们发现某些我们尚不知晓
and would not likely have guessed for a long time.
且意想不到的人类行为模式。
We didn't know that women's mate preferences changed over the cycle.
从前我们并不知道女性的择偶偏好会随着生理变化周期而变化。
Until evolutionary thinking led us to that discovery.
直到演化论观点引领我们得到这个发现。
So that's one point that I want to make.
这正是我要传达的重点之一。
But we've also seen how evolutionary thinking can clarify and unite diverse parts of the human experience,
演化论观点也能厘清和整合许多看似不相关的人类经验，
and help us understand the best and the worst of ourselves,
并协助我们了解自己的优缺点，
from violence and aggression and infidelity to men's care for their children, sexual attraction, sexual pleasure,
从暴力、侵略性和不忠于伴侣，到男性的育儿行为、性的吸引力、性的喜悦，
and even the strength and fragility of romantic love. Thank you.
再到亲密关系的强韧和脆弱等。谢谢！