Has humanity reached 'peak intelligence'?
人类智力是否已达巅峰 未来只会越来越笨？

You may not have noticed, but we are living in an intellectual golden age.

也许你还没有意识到，人类现正处于智力的黄金时期。

Since the intelligence test was invented more than 100 years ago, our IQ scores have been steadily increasing. Even the average person today would have been considered a genius compared to someone born in 1919 – a phenomenon known as the Flynn effect.

自从100多年前出现智力测试以来，人类的智商值一直在稳步增长。跟1919年出生的人相比，如今一个智商平平的人在当时也称得上是天才——这一智商测试结果逐年增加的现象被称为弗林效应（Flynn effect）。

We may have to enjoy it while we can. The most recent evidence suggests that this trend may now be slowing. It may even be reversing, meaning that we have already passed the summit of human intellectual potential.

我们或许应该赶紧享受这一黄金时机吧。因为最新的证据显示，智商的增长速度正在变缓，甚至可能已在逆向倒退，这即是说，我们也许已经过了人类智力所能达到的最高值顶峰，开始走下坡。

Can we have really reached peak intelligence? And if that is the case, what can the subsequent decline mean for the future of humanity?

人类真的已经登上智力巅峰了吗？如果真是这样，之后智力降低对人类未来会意味着什么？

Let’s begin by exploring the ancient origins of human intelligence, from the moment our ancestors began to walk upright more than three million years ago. Scans of fossil skulls suggest that the brains of the first bipedal apes, Australopithecus, were about 400 cubic centimetres – just a third the size of modern humans’.

让我们先从人类智力的远古起源，即300多万年前我们的祖先开始直立行走之时讲起。通过对头骨化石的扫描我们知道，南方古猿（Australopithecus）这种最早的双足猿猴脑容量大约为400立方厘米，仅仅是现代人类的三分之一。

That comes at a serious cost. The brains of modern humans consume around 20% of the body’s energy, so our bigger brains must have offered some serious benefits to make up for those excess calories.

我们也为此付出了巨大代价，身体20%的能量都被大脑消耗了，所以脑容量增大必须得有切实的好处，这才对得起多消耗的卡路里。

There are many potential reasons for this brain boost, but according to one leading theory, it was a response to the increasing cognitive demands of group living.

脑容量激增的可能原因有很多，其中一个主流理论认为，这是群体生活对认知需求越来越高所造成的。

From Australopithecus onwards, human ancestors began to congregate in bigger and bigger groups – perhaps, initially, as a protection against predators, which would have been a serious risk once they began sleeping on the ground rather than the trees. It would also allow individuals to pool resources – helping to spread out some of the risks of living in a changeable environment – and provide shared childcare.

从南方古猿开始，人类祖先聚集的圈子越来越大，最开始可能是为了抵御捕食者，因为从树上转移到地面睡觉之后，捕食者对他们构成了严重威胁。群居还能让大家资源共享——既能降低在变化莫测的环境中生活的风险，也能共同抚育后代。

But as many of us know from our own social circles, living with other people can be hard work: you need to keep track of each person’s personalities, their likes and dislikes, and whether or not they can be trusted with gossip. And if you are working on a group activity, like hunting, you need to be able to follow what each member is doing as you coordinate your activities. For humans today, a lack of social understanding causes embarrassment; for our ancestors, it was a matter of life or death.

但我们中的许多人从自己的社交圈就能发现，与他人一起居住并不容易，得记清每个人的性格特点、喜好厌恶，以及能不能一起八卦东家长西家短。如果是集体活动，譬如打猎，就需要根据他人的行动来调整自己的行为。对今天的人而言，缺乏社会理解会引起难堪，但对人类祖先而言则关乎生死。

Besides presenting those immediate challenges, the larger social groups would have allowed members to share ideas and build on each other’s inventions, resulting in new technological and cultural innovations, such as tools that could improve the efficiency of hunting. And for that to work, you need to have the intelligence to observe and learn from others – providing another push for greater brainpower.

社会群组规模增大后，除了要面对这些直接挑战外，成员们还可以分享想法，并在彼此发明的基础上进行再创造，于是产生了技术与文化创新，譬如提高打猎效率的工具。这就需要拥有观察他人以及向他人学习的智力，这又促进了大脑又一步发展。

By around 400,000 years ago, the brain of Homo heidelbergensis had reached around 1,200 cubic centimetres – just a shade smaller than the brains of modern humans, which are around 1,300 cubic centimetres. When our ancestors left Africa around 70,000 years ago, they were smart enough to adapt to life in almost every corner of the planet. The astonishing cave art suggests they were fully capable of thinking about huge cosmological questions – including, perhaps, their own origins.

大约40万年前，海德堡人（Homo heidelbergensis）的脑容量已经达到了1200立方厘米，只比现代人类1300立方厘米的脑容量小了一点。我们人类的祖先在大约7万年前离开非洲的时候，已经聪明到可以适应地球上几乎各个地方的生活。令人惊叹的洞穴艺术说明他们已经能够去思考宏观的宇宙问题，也许还包括自身的起源。

Few experts would argue that the more recent changes to IQ are the product of this kind of genetic evolution – the timescales are simply too short.

沒有什么专家会认为，人类智商在近阶段的变化是基因进化的产物，因为时间跨度太短了。

It was only 100 years ago, after all, that scientists first invented the “intelligence quotient” to measure someone’s intellectual potential. Their success relies on the fact that many cognitive abilities are correlated. So your ability to perform spatial reasoning or pattern recognition is linked to your maths ability and your verbal prowess, and so on. For this reason, IQ is thought to reflect a “general intelligence” – a kind of underlying brainpower.

毕竟，“智能商数”（简称智商）是100年前才被科学家们发明出来以衡量一个人智力潜能高低的测量评分。智商测量有效是因为人的许多认知能力是彼此相连的。人的空间推理能力和图形认知能力是与数学及语言能力有关，诸如此类还有很多。因此，智商反映的是“综合智力”，相当于大脑的潜在能力。

Although IQ tests are often criticised, a vast body of research shows that their scores can be useful indicators of your performance on many tasks. They are especially good at predicting academic success (which is not surprising, considering that they were initially designed to be used in schools) but also predict how quickly you pick up new skills in the workplace. They are not a perfect measure, by any means – and many other factors will also shape your success – but in general they do show a meaningful difference in people’s capacity to learn and process complex information.

尽管智商测试饱受诟病，但大量的研究表明，智商得分能够体现人在许多工作任务中的表现。在预测学业成绩方面尤为出色（这不出奇，因为智商测试本来就是设计给学校使用的），还能预测出你在工作中掌握新技能的速度有多快。智商测试绝对不是完美标准，许多其他因素也会影响你的成功，但总体而言，智商测验确实能说明人与人之间在学习和掌握复杂信息的方面存在重要差异。

The rise in IQs seems to have started in the early 20th Century, but it’s only relatively recently that psychologists have started taking much notice of the phenomenon. That’s because IQ scores are “standardised” – meaning that after people take the test, their raw scores are transformed to ensure that the median of the population always remains 100. This allows you to compare people who took different forms of the IQ test, but unless you look at sources of the data, it means you would not notice differences between generations.

人类智商之升高似乎早于20世纪初已开始，但心理学家们直到最近才开始关注这一现象。这是因为智商的评分被“标准化”了：人们智商测试后，其原始得分会经过公式换算，以确保人类整体的智商中位数永远是100分。这样就可以比较参加不同形式智商测试者之间的智商高低，但如果不看原始数据的话就看不出不同世代之间的智商差异。

When the researcher James Flynn looked at scores over the past century, he discovered a steady increase – the equivalent of around three points a decade. Today, that has amounted to 30 points in some countries.

研究学者弗林（James Flynn）比较了过去100年来的智商测试得分，发现分数在稳定增长，大约每10年增长3分。有些国家如今总共增长了30分。

Although the cause of the Flynn effect is still a matter of debate, it must be due to multiple environmental factors rather than a genetic shift.

虽然弗林效应的原因尚未有定论，但这肯定是由多重环境因素共同造就的，并非基因的转变。

Perhaps the best comparison is our change in height: we are 11cm (around 5 inches) taller today than in the 19th Century, for instance – but that doesn’t mean our genes have changed; it just means our overall health has changed.

身高的变化或许是个最佳对比：与19世纪时相比，如今我们平均高了11厘米（约5英吋），但这并不能说明人类的基因有变，变化的只是整体的健康情况。

Indeed, some of the same factors may underlie both shifts. Improved medicine, reducing the prevalence of childhood infections, and more nutritious diets, should have helped our bodies to grow taller and our brains to grow smarter, for instance. Some have posited that the increase in IQ might also be due to a reduction of the lead in petrol, which may have stunted cognitive development in the past. The cleaner our fuels, the smarter we became.

有些因素也许会带来双重改变。譬如，医药水平提高、儿童期的感染患病减少，以及饮食营养加强，既令我们身体长得更高，也让大脑变得更聪明。有人指出，智商增加也可能是因为汽油中的铅含量降低，过去铅可能阻碍了认知水平的发展。燃料越清洁，我们就越聪明。

This is unlikely to be the complete picture, however, since our societies have also seen enormous shifts in our intellectual environment, which may now train abstract thinking and reasoning from a young age. In education, for instance, most children are taught to think in terms of abstract categories (whether animals are mammals or reptiles, for instance). We also lean on increasingly abstract thinking to cope with modern technology. Just think about a computer and all the symbols you have to recognise and manipulate to do even the simplest task. Growing up immersed in this kind of thinking should allow everyone to cultivate the skills needed to perform well in an IQ test.

但应该还不止这些，人类社会的智力环境也经历了巨大变革，如今孩子们从很小就开始训练抽象思维和推理能力。譬如在教育过程中，大多数孩子都被教导要以抽象方式思考问题（譬如动物是哺乳类还是爬行类）。我们也越来越倾向于用抽象思维来使用现代技术。譬如，用电脑的时候，即使是最简单的操作也需要识别和处理各种符号。如果在这样的思维方式中成长，就能培养出在智商测试中取得好成绩的技能。

Whatever the cause of the Flynn effect, there is evidence that we may have already reached the end of this era – with the rise in IQs stalling and even reversing. If you look at Finland, Norway and Denmark, for instance, the turning point appears to have occurred in the mid-90s, after which average IQs dropped by around 0.2 points a year. That would amount to a seven-point difference between generations.

无论弗林效应的原因为何，有证据显示，智商增长的时期都可能已经结束，增长的速度放缓，甚至可能正在逆向倒退。以芬兰、挪威和丹麦为例，转折出现在90年代中期，此后智商测试的平均水平每年下降大约0.2分，两代人之间的差距就能达到7分。

Partly because they have emerged so recently, these trends are even harder to explain than the original Flynn effect. One possibility is that education has become slightly less stimulating than it once was – or at least, has not targeted the same skills. Some of the IQ tests used have assessed people’s mental arithmetic, for instance – but as Ole Rogeberg at the University of Oslo points out to me, students are probably more used to using calculators.

这一趋势比之前的弗林效应更难解释，部分原因是此趋势最近才刚刚出现。一种可能的解释是教育不像以前那么激发人的智力，起码所传授的不是应对智力测试。奥斯陆大学的罗格伯格（Ole Roeberg）告诉我，譬如有些智商测试测的是心算能力，但学生们现在都用计算器计数。

For now, it seems clear that our culture can shape our minds in mysterious ways.

目前已经明确，我们的文化会以我们所不知的神秘方式影响我们的心智。

While scientists continue to untangle the causes of those trends, it’s worth questioning what these changes in IQ actually mean for society at large. Has the IQ boost of the Flynn effect brought us the dividends we might have hoped? And if not, why not?

科学家们仍在寻求解答人类智商增加和下降之谜，不过值得我们思考的是，智商的变化对整个人类社会有哪些影响。弗林效应中的智商增加有没有带来我们所希望的好处？如果没有，又是为什么？

A special issue of the Journal of Intelligence recently raised that specific question, and in the accompanying editorial, Robert Sternberg, a psychologist at Cornell University, wrote:

《智力杂志》（Journal of Intelligence）最近出版的一份特刊就提出了这个问题，在相关的文章中，康奈尔大学的心理学家斯特尔伯格（Robert Sternberg）写道：

People are probably better at figuring out complex cell phones and other technological innovations than they would have been at the turn of the 20th Century. But in terms of our behaviour as a society, are you impressed with what 30 points has brought us? The 2016 US presidential election was probably about as puerile as any in our history... Moreover, higher IQs have not brought with them solutions to any of the world’s or the country’s major problems – rising income disparities, widespread poverty, climate change, pollution, violence, deaths by opioid poisoning, among others.

与20世纪之初相比，现在的人能发明更复杂的电话以及突破其他技术创新。但论及社会行为，那增加的30分带给我们的变化你满意吗？2016年的美国总统大选跟历史上的许多愚蠢行为一样幼稚……不仅如此，智商增加后人们也没有找到解决世界以及我们国家重大问题的办法，譬如收入差距扩大、大规模贫困、气候变化、人口问题、暴力以及鸦片中毒死亡等等。

Sternberg may be a little too pessimistic here. Medicine has made huge strides in reducing problems like infant mortality, for example, and while extreme poverty is by no means solved, it has declined globally. That’s not to mention the enormous benefits of scientific technological advances that have, of course, relied on an intelligent workforce.

斯特尔伯格可能有些过于悲观。医学在人类防治疾病增进健康等方面，比如降低婴儿死亡，已经取得了重大进步，虽然极端贫困的问题远远没有解决，但从全球来看已有所缓解。更不必说科学技术进步所带来的巨大好处，当然这有赖于人的智慧。

He is not alone in questioning whether the Flynn effect really represented a profound improvement in our intellectual capacity, however. James Flynn himself has argued that it is probably confined to some specific reasoning skills. In the same way that different physical exercises may build different muscles – without increasing overall “fitness” – we have been exercising certain kinds of abstract thinking, but that hasn’t necessarily improved all cognitive skills equally. And some of those other, less well-cultivated, abilities could be essential for improving the world in the future.

弗林效应究竟有没有显著提高我们的智力？对这个问题持怀疑态度的可不止斯特尔伯格一人。弗林本人曾说，这种提高可能只限于某些特定技能。不同的运动能够锻炼不同肌肉，但整体“健康”可能并没有提高。同理，人一直在训练某些抽象思维能力，但并不一定就提升了所有认知能力。未来如果想让世界变得更好，其他一些我们未能精心培养的能力可能至关重要。

Take creativity. When researchers such as Sternberg discuss creativity, they are not just talking about artistic expression, but more grounded skills. How easily can you generate novel solutions to a problem? And how good is your “counterfactual thinking” – the ability to consider hypothetical scenarios that haven’t yet come to pass.

以创造力为例。当斯特尔伯格等研究人员讲到创造力时，所说的可不只是艺术表现，更是实打实的技能。你能够轻松找到解决问题的新办法吗？你的“假设思维”，即思考并未发生的假定场景的能力有多强？

Intelligence should certainly help us to be more creative, but we do not see a rise in some measures of individual creative thinking over time, as our IQs increased. Whatever caused the Flynn effect, it hasn’t also encouraged us each to think in new and original ways.

智力肯定能帮助我们创新，但智商增长后，衡量人类创新思维的指数并没有随之上升。无论弗林效应的原因为何，这个未知的因素并未激励我们大家以崭新并原创的方式进行思考。

Then there’s the question of rationality – how well you can make optimal decisions, by weighing up evidence and discounting irrelevant information.

此外还有理性，即通过权衡理据摒弃无关信息做出最佳决策的思维能力，你在这方面又表现如何？

You might assume that the more intelligent you are, the more rational you are, but it’s not quite this simple. While a higher IQ correlates with skills such as numeracy, which is essential to understanding probabilities and weighing up risks, there are still many elements of rational decision making that cannot be accounted for by a lack of intelligence.

你可能觉得智力水平越高就越理性，但事情可没这么简单。虽然高智商与计算能力有关，计算能力强有助于理解各种可能性以及权衡风险，但仍有许多理性决策的因素无法用智力不足来解释。

Consider the abundant literature on our cognitive biases. Something that is presented as “95% fat-free” sounds healthier than “5% fat”, for instance – a phenomenon known as the framing bias. It is now clear that a high IQ does little to help you avoid this kind of flaw, meaning that even the smartest people can be swayed by misleading messages.

讨论人类认知偏差的文献已汗牛充栋。譬如一个例子是“95%脱脂”听起来比“5%的脂肪”要健康，这一现象叫做框定偏差。现在已经知道，智商高也不能免除这类问题，最聪明的人也会被误导性信息所左右。

People with high IQs are also just as susceptible to the confirmation bias – our tendency to only consider the information that supports our pre-existing opinions, while ignoring facts that might contradict our views. That’s a serious issue when we start talking about things like politics.

高智商的人也一样会受到确认偏差的影响，容易只考虑那些符合我们既有观点的信息，而忽视那些与我们观点相违的事实。这在我们谈论政治时是个严重的问题。

Nor can a high IQ protect you from the sunk cost bias – the tendency to throw more resources into a failing project, even if it would be better to cut your losses – a serious issue in any business. (This was, famously, the bias that led the British and French governments to continue funding Concorde planes, despite increasing evidence that it would be a commercial disaster.)

高智商也免不了陷入沉没成本偏差，即便止损更合理也要往失败的项目上投入更多资源的这种认知偏差。此认知偏差在任何行业都很严重。（这种认知偏差导致英国和法国政府一直不断注资协和飞机，尽管不断有证据表明这会酿成商业灾难。）

Highly intelligent people are also not much better at tests of “temporal discounting”, which require you to forgo short-term gains for greater long-term benefits. That’s essential, if you want to ensure your comfort for the future.

智商高的人若遇“时间贴现”的问题也不比智商次于他的人更胜一筹。“时间贴现”理论要求人们放弃短期所得来换取更好的长期利益。如果你想作长远打算，能舒适地度过后半生，那这种选择就是正确的。但事实上，不论智愚，多数都会选择短期利益。

Besides a resistance to these kinds of biases, there are also more general critical thinking skills – such as the capacity to challenge your assumptions, identify missing information, and look for alternative explanations for events before drawing conclusions. These are crucial to good thinking, but they do not correlate very strongly with IQ, and do not necessarily come with higher education. One study in the USA found almost no improvement in critical thinking throughout many people’s degrees.

除了抵制这些认知偏差外，还有一些更基本的批判思维能力也非常重要，譬如能够质疑自己的臆测，能分辨被漏掉的信息，以及能在得出结论之前寻找其他解释的能力。这些都是优秀思维的关键因素，但跟智商联系并不紧密，也不一定要受过高等教育才会具备。美国的一项研究发现，许多人教育程度升高，但批判性思维却几乎是原地踏步。

Given these looser correlations, it would make sense that the rise in IQs has not been accompanied by a similarly miraculous improvement in all kinds of decision making.

既然相关性这么低，也就是说，智商提高后，各种决策能力并没有随之奇迹般地一同进步。

As I explain in my book on the subject, a lack of rationality and critical thinking can explain why financial fraud is still commonplace, and the reason that millions of people dish out money on quack medicines or take unnecessary health risks.

正如我在书中所解释的，缺乏理性和批判性思维是金融诈骗依旧普遍的原因，也是为何会有成百上千万人掏钱去买没药效的药，或是去承担毫无必要的健康风险。

For our society, it can lead to medical errors and miscarriages of justice. It may have even contributed to disasters like the Deepwater Horizon oil spill and global financial crises. It is also contributing to the spread of fake news, and the huge political polarisation on issues like climate change – preventing us from finding an agreed solution before it is too late.

对社会而言，理性和批判性思维的缺失会导致医疗错误与司法不公，甚至与深海地平线（Deepwater Horizon）钻井平台漏油事故以及全球金融危机等灾难也有关系。与此同时还助长了假消息的传播，令我们在气候变化等问题上出现严重的政治两极化立场，以至于阻碍我们及时找到各方都能接受的解决办法。

Considering the sweep of human history to date, then, we can see how our brains grew to live in increasingly complex societies. And modern life, while allowing us to think more abstractly, does not appear to have corrected our irrational tendencies. We have assumed that smart people naturally absorb good decision making as they go through life – but it is now clear that is not the case.

想想迄今为止人类历史经历的风风雨雨，那么，我们就能看出我们人类大脑智力是如何适应日渐复杂的社会而增长。现代生活虽然令我们能够更加抽象地认知世界，但却并没有纠正人类的非理性倾向。我们以为聪明的人在生活中会自然而然地做出明智的决策，但现在已经清楚知道，事实并非如此。

Looking to the future, the “reverse Flynn effect” and the potential drop in IQs should certainly cause us to take stock of the ways we are using our brains, and preventing any further decline should undoubtedly be a priority for the future. But we might also make a more concerted and deliberate effort to improve those other essential skills too that do not necessarily come with a higher IQ.

展望未来，“反向弗林效应”以及可能出现的智商下降会促使我们评估对大脑的使用方式，避免智商进一步下降是未来的首要任务，这一点毋庸置疑。不过我们可能也会更加协调一致地专门做出努力，去提升那些不一定意味需要高智商的其他技能。

We now know that this kind of thinking can be taught – but it needs deliberate and careful instruction. Promising studies of doctors’ decision making, for instance, suggest that common cognitive errors can be avoided if they are taught to be more reflective about their thinking. That could save countless lives.

我们现在知道，这类思维是可以传授的，但是需要专门的悉心指导。一些针对医生决策所进行的研究带来好消息。研究发现，如果医生被教会诊治病人能反复思考自己的想法，就能避免常见的认知错误，拯救无数生命。

But why not teach these skills in early education? Wandi Bruine de Bruin, now based at Leeds University Business School, and colleagues have shown that discussions of decision making errors can be incorporated in the history curriculum of high school students, for instance. Not only did it improve their performance of a subsequent test of rationality; it also boosted their learning of the historical facts too.

但为何不在教育的早期阶段就教授这些技能呢？布莱恩（Wandi Bruine de Bruin）在利兹大学的商学院（Leeds University Business School）工作，她和同事们表示，可以将对决策错误的讨论纳入高中历史课程。这不仅提升了学生们之后在理性测试中的表现，也能提升他们对历史真相的认识。

Others have attempted to revitalise the teaching of critical thinking in schools and universities – for instance, a discussion of common conspiracy theories teaches students the principles of good reasoning, such as how to identify common logical fallacies and how to weigh up evidence. Having taken those lessons, the students appear to be more sceptical of misinformation in general – including fake news.

也有人想在学校和大学里重振批判性思维教学，例如，讨论常见的阴谋论能教给学生优秀推理的准则，譬如该如何找出常见的逻辑错误以及如何权衡事实依据。参加这些课程后，学生们整体而言会对包括假新闻在内的错误信息更能抱持怀疑的态度。

These successes are just a small indication of what can be done, if rationality and critical thinking are given the same kind of respect we have traditionally afforded our other cognitive abilities.

我们一直都很重视认知能力，如果对理性思维与批判性思维也能给予同样的重视，能做的还有很多，这些成功不过是区区几例而已。

Ideally, we might then start to see a steep rise in rationality – and even wisdom – in tandem with the Flynn effect. If so, the temporary blip in our IQ scores need not represent the end of an intellectual golden age – but its beginning.