​​​Adolescent behavior doesn’t make sense (except in the light of cultural evolution)

青春期行为不合情理（除非从文化进化方面考虑）

​Adolescence is a strange developmental period. The oddity of the teenage years is particularly stark to parents, who watch a major transition unfold as their children move through adolescence. That child who was focused on life with her parents — even if she played it cool by pretending not to be focused on her family — suddenly turns outward. Time by herself becomes valued over time with her family, and time with her peers becomes valued over all else. Some adolescents become suddenly convinced that their parents know nothing (and often are not afraid to make that belief known), but all teens begin experimenting with ideas that are foreign or even counter to those with which they were raised. In industrialized societies, popular culture — or running counter to it — also becomes important to the developing teen: contemporary music, movies, fashion, and sports all maintain particular attraction. And then there are the behaviors that are so vexing to parents: drinking, drugs, sex, dangerous driving, and all manner of other risky endeavors. From the parental perspective, it is easy to ask why does adolescence exist?

青春期是个奇特的发育时期。十几岁孩子的古怪表现简直要让他们父母发疯，这些父母所目睹的，是孩子们走过青春期时发生的一次重大转变。一个曾经专注于家庭生活的孩子——即使她为耍酷而假装不在乎家人——突然转向外面的世界。对这时的孩子来说，自处比和家人相处更重要，而跟同伴在一起则成了最重要的事。一些孩子突然就认定他们的父母什么也不懂——并且往往毫不在意地表露这个信念。而且，所有十多岁的孩子都开始尝试那些与他们被抚养成人时所依据的观念完全不同甚至恰恰相反的想法。工业化社会的流行文化——或者与之背道而驰的东西——也是塑造青少年的重要因素：当代音乐、电影、时尚和体育等都有着特殊的吸引力。这便有了那些令父母们很头疼的行为：喝酒、嗑药、性行为、危险驾驶，以及其它所有危险的尝试。站在父母的角度很容易问一句：为什么会有青春期？

Biologically speaking, it is clear that adolescence is a time of profound developmental transformation. Hormonal changes trigger the growth of additional body hair and the maturation of the reproductive system, preparing the adolescent body for potential parenthood. Fat distribution and overall muscle mass both undergo major shifts, transforming the lithe, androgynous body of a child into the sexually-distinctive body of a man or a woman. While the hormonal shifts of adolescence are what we most often associate with this developmental phase, the neurological changes it brings are just as dramatic. Historically characterized as a period of psychological “storm and stress”, adolescence can now be understood through the lens of modern neuroscience. Imaging studies have shown that the brain undergoes major remodeling during adolescence[1, 2]; these changes may be the proximate cause of many of the adolescent behaviors that non-adolescents struggle to understand.

在生物学上，青春期显然是具有深远意义的生长发育转变期。激素改变触发了体毛生长和生殖系统成熟，为可能到来的生育做准备。脂肪分布和全身肌肉块都有变化，将小孩子性别不彰的轻盈体貌改造成有明显性征的男人或女人的身体。我们通常把青春期与激素变化相联系，但此时神经系统的改变同样显著。如今，我们能透过现代神经科学的镜头了解青春期这一在历史上曾被称为心理“风暴与压力”的发育期。影像学研究表明，青春期是大脑发育的重要重构期[1,2]；这些变化可能是让不身处青春期的人很难理解的青春期行为的直接原因。

Explaining the anatomical and physiological shifts of adolescence from an evolutionary perspective is rather simple: during the teenage years, the child becomes an adult capable of having her own children. That humans take so many years to be capable of reproducing is remarkable; that such change eventually happens is not. But what about adolescent behaviors? Why is the transition to reproductive maturity accompanied by such dramatic behavioral shifts, including behaviors that have the potential to put the developing adolescent at risk of dying before reaching full adulthood? Can the behavioral characteristics of adolescence be explained from an evolutionary perspective as easily as their physiological and anatomical counterparts?

以进化的观点解释青春期解剖学和生理学变化相当简单：在十几岁的年纪里，一个孩子长成了可以生育自己孩子的成年人。人要生长许多年才能获得生殖能力，这一点很不寻常，而这一转变的最终发生却并没什么。但是，怎么看待青春期行为？为什么生殖成熟的转变伴随如此令人抓狂的行为改变，包括在完全成年之前出现可能将自己置于死亡险地的行为？从进化角度剖析青春期行为特征，和从生理和解剖学角度一样容易吗？

Contemporary child psychology views adolescent behavior as the product of two forms of simultaneous neurological development: “sensation seeking” and “impulse control” [1]. While sensation seeking is thought to peak in the adolescent years, impulse control develops more slowly, leading to “maturational imbalance” [3] as these two processes unfold at different paces. Unable to keep up with the teen’s instinct to seek out novelty, impulse control fails to prevent behaviors that are moderated in adults, including risky behaviors. This portrayal of adolescence makes a certain kind of intuitive sense: we all know that adolescents like novel experiences, and a lot of teens have a hard time controlling impulses, some of which put them in harm’s way. But why did this imbalance between impulse control and novelty seeking evolve? Is impulse control so difficult to develop that it simply can’t keep pace with the allure of the new and different? Or have these two neurological modules — one saying “go for it”, and the other more weakly saying “maybe you shouldn’t” — evolved to develop at different paces for some adaptive reason? We shouldn’t assume that every behavior evolved in response to selective pressures, but the behavioral shifts of adolescence are so profound and potentially costly that it’s hard to imagine that they did not evolve for some adaptive reason.

当代儿童心理学把青春期行为看作两种心理模式的神经发育过程同时展开的结果，这两种模式就是：“寻求刺激”和“控制冲动”[1]。寻求刺激在青春期达到高峰，而控制冲动的发展慢很多，二者以不同的速度发展导致“成熟失衡”[3]。控制冲动的神经功能跟不上十几岁青少年寻求新奇的本能，限制不了那些成年后被节制的行为，包括危险行为。这种青春期描述形成一种直观感觉：我们都知道十几岁孩子喜欢新奇体验，很多孩子很难控制冲动，有些冲动把他们推到了受伤害的路上。但是，为什么控制冲动和寻求刺激之间会发展出不平衡？是控制冲动难以发展以至于就是跟不上新奇事物的诱惑力步伐吗？或者两个神经模块——一个声音说“去，干吧”，另一个弱弱地说“也许，不可以…吧”——因为一些适应性的原因而以不同速度发展吗？我们不应该假设任何行为的进化是出于选择压力，但鉴于青春期行为改变如此意义深刻，潜在成本如此高昂，很难想象其中没有适应性理由。

The adaptive value of adolescent behavior isn’t immediately obvious, placing the “maturational imbalance” theory of adolescence on shaky evolutionary ground. Imagine an individual who develops strong impulse control just as they emerge from middle childhood. From a perspective of physical risk, this would be the ideal time for impulse control to develop: the child no longer maintains such close contact with the parent — and that parent’s judgment of what is and is not safe — and simply develops his own impulse control to avoid risk, potentially based on behavioral rules learned from the parent. Is it really possible that the requisite impulse control simply can’t develop until the young person is in her mid-twenties? And if impulse control really requires that much time to develop, wouldn’t it have been adaptive for human offspring to remain dependent “children” for even longer periods, until sufficient impulse control could be developed? If the evolved developmental pattern of adolescence puts teens at inordinate risk, it seems likely that natural selection would have long ago selected against this developmental pattern. That such a pattern exists is therefore paradoxical.

青春期行为的适应性价值并非显而易见，这就让青春期“成熟失衡”理论在进化论上不太站得住脚。试想一个人从童年中期开始发展出了强有力的对冲动的控制。从防控身体危险的角度，青春期是发展冲动控制的理想时间：孩子们不再与父母（及其对安全与否的判断）保持紧密联系，只潜在地基于从父母处学到的行为规则发展自己控制冲动的能力以躲避危险。年轻人是否真的有可能要到二十五岁左右才能发展出必需的控制冲动的能力？如果发展这种能力确实需要很长时间，那么在获得足够的冲动控制能力之前，人类后代在更长时间内作为依附于父母的孩子是否才更符合适应性原理呢？如果青春期进化发展模式将置十几岁孩子于过度危险中，那么自然选择很可能很久以前已经剔除了这种模式。因此，这种模式的存在是个矛盾。

Some of the greatest biological paradoxes presented to early naturalists also revolved around risk: why would animals engage in ritual combat with other members of their species, or be adorned with conspicuous colors and anatomical ornaments, or spend so much time and energy engaging in elaborate displays? All these behaviors are risky — or at least highly costly — and therefore seem ripe for removal by natural selection. A great many of these paradoxes were resolved by considering that reproductive benefits might outweigh any costs related to survival. Understanding that sexual selection — driven by the mating environment rather than the broader ecological environment — could lead to the evolution of costly traits was a major advance in evolutionary theory. Survival is only valuable if it leads to successful reproduction, which means that risky behaviors with the potential to increase mating success have a good shot at surviving the evolutionary process.

早期博物学家所面对的一些出名的生物学悖论，也围绕危险这个话题打转：为什么动物与同类搞仪式性战斗？或用醒目的颜色装饰自己，用身体器官打扮自己，抑或费时费力参与精心编排的禀赋展示？这些行为都是危险的——或者至少成本非常昂贵——故而似乎是应该被自然选择所淘汰的。如果考虑到繁衍收益可能超过生存成本，很多悖论便迎刃而解。理解性选择——由交配条件而非更宽泛的生态环境所驱动——可能导致高成本性状的进化，是进化理论的重大进步。生存的唯一目的是成功繁衍下一代，这意味着提高交配成功率的危险行为能在进化过程中以较高的概率存在下去。

A big part of adolescent change is sexual in nature. While middle childhood is characterized by a preference for the company of same-sex friends, adolescents shift to mixed-sex social groups and begin seeking out sexual partnerships. So it wouldn’t be entirely unreasonable to suggest that the seemingly-inexplicable behaviors of adolescence are related to mating. As the adolescent body matures, wouldn’t it make sense for adolescent behaviors to shift towards displays that might appeal to a potential mate? Perhaps the change in social orientation outside of the family, the interest in what peers value, and the desire to spend all one’s time with those peers are all about finding a suitable mate. Impulse control may be inadequately developed precisely because the resulting “maturational imbalance” leads to risky behaviors that serve as mating signals to the opposite sex. A particular level of elevated risk fostered by adolescence might be compensated for by reproductive success reaped by showing off for potential mates in one’s peer group.

大部分青春期变化在本质上是性方面的。孩童中期的特点是偏好与同性朋友交往，青春期转移到混合性（同性和异性并存）的社交团体，并开始出去寻找性伙伴。那么认为貌似费解的青春期行为与交配有关也就并非完全没有道理了。随着身体成熟，那些为了吸引性伴侣交配而展示魅力的青春期行为怎么会没有意义？也许，家庭之外的社交，投同伴所好，以及希望整日和同龄人在一起，都恰恰是为了寻找合适的伴侣。冲动控制发展不足恰恰是因为“成熟失衡”导致的危险行为能作为求偶信号传达给异性。青春期（行为）导致的生存风险一定程度的升高也许可以通过向同龄人社交群体里的潜在交配对象炫耀以达到成功繁衍后代的目的而获得补偿。

The problem with viewing adolescent behavior from a purely reproductive perspective is that adolescence is not an ideal time to reproduce. Although it’s hard to determine how to compare what we know about the teenage parenthood of today with what might have applied to our ancestors, it is clear that in a diversity of contemporary societies — including many that are at the same small scale as our ancestral populations — the success rate of adolescent parents is dramatically lower than that of older parents [4]. Being anatomically ready to be a human parent is not the same as being psychologically, culturally, and socially prepared for being a human parent. Perhaps adolescent mating displays have a long shadow, impressing potential mates that in adulthood will become actual mates. But given that maximum reproductive output occurs just as adolescence comes to an end — and characteristic adolescent behaviors subside — it seems a bit of a stretch to suggest that all of the oddity of adolescence is related to reproduction. It’s also somewhat paradoxical that adolescent risk-taking is more extreme in males, whose actual reproductive success tends to occur at a later age than females. Adolescent behaviors might serve as a kind of practice for mate competition, but are they a direct form of mating display? Probably not.

只从繁衍的角度解读青春期行为的问题是，青春期不是繁衍后代的理想时间。尽管我们不清楚如何比较我们所知道今天十几岁少年当父母的情况与我们祖先的情况，但很明显在包含和我们祖先人口规模相同的群体的各种各样的当代社会群体中，青少年当父母的成功率较成年后为人父母的小之又小[4]。在身体上准备好为人父母与在心理、文化和社会层面上准备好不是一回事。可能青春期求偶行为带有长时间的影响，能让潜在的伙伴关系成年后变成实际的伴侣。考虑到最佳繁衍能力正值青春期即将结束之际——此时典型的青春期行为消退了，如果把所有青春期的怪异表现都以繁衍后代来解释就有点牵强了。还有一点矛盾的是，男性青春期冒险行为比女性更极端，而其实际成功繁衍后代的年龄倾向于晚于女性。青春期表现也许可以作为一种男性间竞争的练习，但这是求偶展示的一种直接表现形式吗？可能并不是。

Whenever we try to account for a difficult-to-explain behavior in contemporary human societies, it is important to ask would this behavior have been difficult to explain in early human societies? Perhaps adolescent behaviors would make a whole lot more sense if we could see how they played out in our ancestral environments. Given how much humans have reshaped our environment via our rapidly-evolving culture, it is not unreasonable to suggest that behaviors that seem maladaptive in our current environment might have been adaptive in the physical and social environment experienced by our ancestors. A variety of contemporary human maladies – ranging from obesity to violent crime – have been well-explained as evolutionary mismatches: evolved characteristics that would have aided our ancestors become problematic in our dramatically-transformed contemporary cultural environment. Perhaps the paradoxical risky behaviors of adolescence result from a mismatch between current and past human environments [5]. Our ancestors came of age in mixed groups composed of children, adolescents, and young adults, whereas today adolescent social groups are often highly-stratified by age. Perhaps some of the excesses of contemporary adolescence result from this age stratification. Or perhaps the risks available to modern teens are the problem: lower impulse control might not have been such a problem for earlier adolescents living in an environment filled with a whole lot fewer intoxicants and motor vehicles.

无论何时，当我们试图理解一个在当代人类社会中难以解释的行为时，问一个“这种行为在早期人类社会一直很难解释吗”的问题非常重要。把放在我们祖先生活的环境中进行考量，青春期行为就合理多了。鉴于人类文明快速进化很大程度改造了我们的环境，因此有理由认为与当下环境不合拍的行为，可能适应于我们祖先所经历的物质和社会环境。当代人类的大堆问题和弊病——从肥胖到暴力犯罪——可以用进化失配来解释：曾帮助过我们祖先的进化特征在快速变化的当代文明环境下成为了问题。或许青春期的危险矛盾行为源于当今和从前的人类生存环境之间的失配[5]。我们祖先的群体混合了儿童、少年和青年和成年人的各种年龄段，而现在的青少年群体常常按年龄高度分层。也许一些当代青春期过激行为是年龄分层的结果。抑或现在让青少年接触到的风险本身才是问题：对于早期生活在几乎没有麻醉品和机动车环境中的青少年，控制冲动能力低下可能不会有大麻烦。

Explaining paradoxical traits as the result of evolutionary mismatch doesn’t just require that we show that the contemporary environment is dramatically different than the ancestral environment: the adaptive value of a trait in the ancestral environment also needs to be reasonably established. Maybe today many people become obese in our calorie-abundant environment because their ancestors survived by developing a taste for infrequently-available high-calorie foods. Maybe today some people are prone to violent crime because a willingness to engage in retributive punishment would have aided cooperation in the small social groups of our ancestors. These explanations are feasible because they explain a paradoxical trait based on both the past and present environments. The problem with explaining adolescent behaviors as a case of “evolutionary mismatch” is that it isn’t readily clear what adaptive function these behaviors would have served in the past. If adolescents used to exist in mixed-age groups – perhaps in the semi-parental role of “helper at the nest” with younger relatives – why would a preference for social company outside of the family evolve? If adolescents used to have less risky forms of display available, what function did these safer forms of display serve to developing adolescents? These questions are not unanswerable, but the lack of compelling answers calls into question the idea that the paradoxical nature of adolescence emerges from evolutionary mismatch.

以进化失配来解释自相矛盾的特征，不仅需要我们认识到当代环境与祖先环境的明显不同，在祖先环境下这些特征的适应价值也需要合理认定。也许今天许多人在高热量食品充足的环境里变肥胖了是因为人类祖先靠着进化出对那时并不常见的高热量食物的偏好而得以幸存下来。也许今天有的人有暴力犯罪倾向是因为复仇意愿有利于人类祖先那种小社会群体的合作。这些解释站得住脚，因为它们能基于过去和现在的环境对矛盾的特征进行解释。用“进化失配”解释青春期行为的问题是，我们并不清楚这些行为在过去的适应性作用。如果从前青少年与其他年龄人混居——他们也许在抚养年幼的亲人中扮演“鸟巢帮手”的半父母角色——为什么他们没有进化出对家庭以外的社交伙伴的偏好？如果青少年在过去有风险更小的魅力展示形式，那么这些更安全的展示形式在青春期发展中有什么作用？这些问题并非无法回答，但缺乏令人信服的答案，这就让人对青春期的矛盾特征源自进化失配的观点产生了疑问。

All of the explanations of inexplicable adolescent behavior that we have considered thus far relate directly or indirectly to biological fitness. That’s not especially surprising given that we have been trying to explain adolescent behavior from an evolutionary perspective. But biological evolution isn’t the only driver of human behavior: we are also a highly cultural species — perhaps the only truly cultural species — and that means that we cannot discount the possibility that adolescent behavior is driven by cultural evolution. Are adolescent behaviors better understood as evolved to improve cultural fitness?

到目前为止对所有令人费解的青春期行为的解释都直接或间接地与生物适应性相关。这不足为奇，因为我们一直试图从进化角度解释青春期行为。但生物进化并非人类行为的唯一驱动力，我们也是一个高度文化性的物种——也许是唯一真正具有文化的物种——这意味着我们不能忽视文化的进化驱动青春期行为的可能性。从提高文明适应的角度能更好地理解青春期行为吗？

To understand adolescence from a cultural evolutionary perspective we first need to consider the nature of cultural transmission before adolescence. From birth, children depend heavily on their parents for survival. Initially this survival revolves around the provision of food and security, but eventually parents begin to provide something else: cultural education. We initially learn most of our fundamental cultural survival skills — how to obtain resources, how to make and use tools, and how to behave in social groups — from our parents. This learning occurs in early and middle childhood, periods in which contact with parents and other members of the family create the primary social environment for the developing child.

为了从文化进化角度理解青春期，我们先考察一下青春期以前的文化传承的本质。出生伊始，孩童的生存非常依赖父母。起初这种生存围绕着食物供给和安全保证，但最终父母开始提供别的东西：文化教育。最初我们从父母处学习大部分文化方面的基本生存技能，例如如何获取资源，如何制造和使用工具，以及在社会群体中如何表现。我们在童年早期和中期学习这些技能，在此期间，与父母和其他家庭成员的接触给小孩子创造了成长发育的主要社交环境。

Learning from parents and other close family members is a good cultural strategy for children. As younger children are extremely vulnerable, they primarily need the protection of trusted adults. Getting that protection means spending a lot of time with members of the family, which provides plenty of opportunity to observe and imitate familial traditions: we first learn to live the cultural lives of our closest relatives. And as some forms of cultural teaching are time-consuming and therefore costly to the teacher, the child’s most reliable investors in her cultural education are close relatives. That most of our earliest culture comes from our families is not surprising.

跟父母和其他家庭成员学习对孩子是很好的文化学习策略。年龄小的孩子极其脆弱，他们首先需要值得信赖的成年人的保护。获得这种保护意味着大量时间与家人待在一起，这给孩子提供了充足的机会观察和模仿家族传统：先学会按家人的文化生活方式去生活。而有些形式的文化教育非常费时，老师需要付出昂贵成本，因此给一个孩子文化教育最可靠的投资者是他的亲人。我们最早学习的大多数文化来自于家庭，这不足为奇。

But is mastering only the cultural traditions of one’s family the best survival strategy? What if my family’s cultural traditions are less effective than those of other families? Or what if the ecological or social environments of a child end up being dramatically different than the environments experienced by her parents? As practical and logical as it is to absorb the culture of one’s family, doing so also comes with potential risks. What if there were a way to buffer some of those risks while maintaining the potential benefits of having learned one’s familial culture?

但是，仅仅掌握一个家庭的文化传统是最好的生存策略吗？如果自家文化传统与别人家庭相比不那么有效，怎么办？或者，如果一个孩子最终的生活或社交环境与其父母所经历的迥异，怎么办？吸收自己家庭的文化尽管符合实用性和逻辑性，这样做也带来了潜在的风险。在获得学习家庭文化的潜在收益的同时，是否有一个途径可以缓冲一些风险呢？

Enter adolescence.

进入青春期。

Viewed from a cultural evolutionary perspective, the counter-intuitive behaviors of adolescence suddenly make a ton of adaptive sense. Delayed development of so-called “impulse control” might end up being a real adaptive asset: freed from the impulse to simply follow the cultural rules of her family, the developing adolescent spends a distinct period of time experimenting with cultural ideas absorbed from her peers. Think of it as broadening the cultural portfolio: the adolescent brain temporarily rejects many of her family’s ideas in order to discover, explore, and assess new ideas. Throughout adolescence, these new ideas compete with familial ideas, creating psychological turmoil and unpredictable behaviors. As adolescence subsides, the battle between ideas gained from one’s relatives and ideas gained from peers and other non-relatives also subsides. Exiting adolescence, most adults carry around a mix of cultural ideas, some from parents and some from peers. If this novel mix of ideas allows for better prospects of survival and reproduction, the cultural experimentation and resulting risk of adolescence was well worth the cost.

从文化进化角度看，青春期那些违反直觉的行为顿时在适应性层面上非常合理。所谓“冲动控制”的迟缓发育最终可能是一种真正的适应性财富：从只遵从家庭的文化规则的冲动中解放出来，青春期是一个体验来自同龄伙伴的文化观念的独特时间段。我们将此看成对文化内容的拓展：青春期大脑为了发现、探索和评估新思想，暂时拒绝了来自家庭的意见。在整个青春期，新观念与来自家庭的观念斗争，产生了心理上的混乱和不可预知的行为。随着青春期结束，来自家庭的观念与来自同龄伙伴及其他非亲属的观念之间的战斗也消退了。走过青春期，大多数成年人携带着来自父母和同侪观念的混合文化理念。如果这种新的理念组合给生活和繁衍后代带来更好的预期结果，那么进行文化实验以及它导致青春期的危险就是值得的代价。

Adolescence has always been viewed as a process of breaking free of the family, of preparing to live independently of one’s parents. But viewed through a cultural evolutionary lens, the nature of this separation process comes into much sharper focus. What adolescence has evolved to do is to break each individual free of some or even most of the culture of the family. When it comes to future survival, it is simply too risky to rely solely on the cultural ideas passed on by one’s parents; it pays to supplement or even replace parentally-inherited culture with ideas gained from individuals from outside one’s family, most prominently one’s peers. That peer group’s developing culture, which is in the process of resolving and defining itself during each cohort’s adolescent period, is of particular importance, because the collective culture of each age cohort will become the most important social environment faced by members of that cohort. Stay too loyal to your parent’s culture as an adolescent and risk falling catastrophically out-of-step with the cultural environment you will soon experience as an adult.

青春期一直被看作是脱离家庭束缚、为离开父母独自生活做准备的过程。但如果从文化进化的角度来看，这种脱离家庭的过程的本质要清晰得多。青春期要做的事就是打破某些（甚至大部分）家庭文化对个人的束缚。对未来的生存来说，仅仅依靠从父母处传承来的文化理念实在太冒险了；青春期付出代价，获得来自家庭之外主要是同侪的思想观念，用来补充甚至替代从父母处继承的文化。在各个成员青春期化解和定义自我的过程中的同侪群体的文化发展特别重要，因为每个年龄群的集体文化是该年龄群成员需要面对的最重要的社交环境。青春期少年如果过分依赖来自父母的文化，便会有与成年后很快将要面对的成人文化环境发生灾难性不合拍的风险。

Adolescence as a major human developmental phase evolved quite recently, emerging just before (or as) culture took off in the hominid lineages [6]. This may not have been a coincidence. As our species came to rely more and more on tools as an extended phenotype and ideas as a way of fostering cooperation, the need to obtain a diverse, effective set of cultural ideas in a rapidly-evolving social environment may have given rise to a distinct developmental period in which plenty of outside ideas are allowed to compete with ideas inherited from one’s parents. Historically, psychological theories of adolescence have suggested that the development of impulse control simply couldn’t keep pace with an evolving drive towards greater sensation seeking. But what seems like a much more reasonable hypothesis is that the adolescent imbalance between increased sensation seeking and “inadequately developed” impulse control is adaptive, or at least evolved in an environment where it was adaptive.

青春期作为人类重要发育阶段进化得相当晚，仅仅在原始人类家族产生文化之前（或同时）出现[6]。这可能不是巧合。随着人类越来越依赖将工具作为延伸表现型并依赖思想作为促进合作的方式，在快速发展的社交环境里获得一套多样且有效的文化理念的需求可能产生了独特的发育阶段。在这个阶段中，大量来自外部的观念被允许挑战继承自父母的观念。从历史上看，青春期心理学理论研究表明，冲动控制的发展速度无法跟上更快速的感官需求驱动的发展。但一个似乎更合理的假设是，青春期情感需求增加与冲动控制“发展不足”的失衡是适应性的，或者至少是在它进化于其中的那个环境中是适应性的。

This doesn’t mean that modern adolescents don’t face evolutionary mismatch problems. Humans at all developmental stages now have access to a breadth of cultural ideas and technologies — including ones that pose significant risk — far greater than the limited cultural palette of our ancestors. So perhaps some of the “problems” of current-day adolescence do stem from a mismatch. But the unprecedented cultural diversity that we now experience might also create the environment in which adolescent novelty-seeking behaviors are most adaptive. It’s pretty much impossible to rely solely on your parents for essential cultural skills these days, because culture is evolving so rapidly and no single person can possibly possess all the cultural ideas and skills that their offspring might fruitfully utilize in their future adult life. The healthy adolescent displays a culturally-adaptive behavioral pattern, supplementing or partially modifying the culture learned from their family. Viewed as a distinct developmental period evolved to allow individuals to improve their biological prospects by broadening their cultural portfolios, adolescence and all of its exploration, experimentation, and risk-taking make plenty of adaptive sense.

这并不是说青春期在现代不会面对进化失配问题。目前，处在任何发育阶段的人类都可以获得海量的文化思想与技术——包括那些会带来相当危险的思想和技术——远超我们祖先有限的文化广度。因此，也许今天的一些青春期“问题”就是来自失配。但是，我们正经历的前所未有的文化多样性也可能创造出了让青少年求新求异行为最具适应性的环境。当今只通过父母学习必需的文化技能几乎是不可能的，因为文明如此迅速的发展，没有一个人可以掌握其后代在未来成年生活中可以卓有成效地运用的所有文化思想和技能。健康的青春期表现出在文化上具有适应性的行为模式，用以补充或部分修正来自家庭的所学。如果青春期被视为一个特点鲜明的发育阶段，人类在此阶段是通过拓宽其文化意义上的人生阅历提高自身的生物学前景的话，青春期及其探索、实验和冒险行为从适应性角度来看非常合理。

参考文献

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