Why Your Brain Actually Works Better in Winter
为什么你的大脑在冬天更好用？
It was terrifyingly cold in New York this weekend, and this cold snap occurred right as we’re entering the postholiday doldrums. It’s around the time of the year when people start to talk about seasonal changes to their mood and energy level — most commonly, seasonal affective disorder, or SAD. While SAD is a relatively new condition — it stems from research in the ‘80s — it has become a huge part of how we in the colder climes discuss winter.
这个周末，纽约出奇的冷，寒流在我们假日后的沉闷期突然来袭。差不多就是这时候，人们开始谈论他们情绪和精力的季节性变化——季节性情感障碍（SAD）是最常见的话题之一。虽然SAD是一种历史较短的疾患（起源于1980年代的研究），但它已然成为身处更冷气候中的人们谈论严冬时津津乐道的话题。
Everyone knows how winter affects certain people: It lowers their mood, makes them more prone to depression, and, in some cases, slows their mind to a crawl. There’s a reason for the popular image of someone wanting to just curl up in bed to wait out the duration of a frigid February afternoon.
大家都知道冬季会对特定人群产生何种影响：寒冬会使他们的心情变差，让他们更容易患抑郁症，在某些情况下还会让他们的思维变迟钝。二月里一个严寒的下午，某人只想蜷缩在被窝中，静待时间流逝——这种大众印象自有缘由。
But scientists are coming to realize that this might not be quite right. A pair of new studies challenge many of the popular assumptions about the psychological effects of wintertime, suggesting that we should look at the season in a new, brighter light. The weather might be gray and chilly, but the latest science says we humans are better at dealing with this than we usually give ourselves credit for, both in terms of our mood and the basic functioning of our brains.
但科学家开始意识到这或许并不准确。两项最新研究挑战了许多有关冬季带来的心理影响的流行假设；这提示我们应该用一种新的、更加乐观的视角看待这个季节。冬日的天气或许是灰暗而寒冷的，但最新研究表明：人类应对寒冬的能力比我们自以为的更好——无论是情绪方面，还是大脑基本功能方面。
The first study is a massive investigation published recently in Clinical Psychological Science involving 34,294 U.S. adults. It casts doubt on the very notion that depression symptoms are worse in the winter months.
第一项研究是最近发表在《临床心理科学》上的大型调查，共计34294名美国成年人参与。这项研究质疑了“冬季会恶化抑郁症状”这种观念。
The researchers, led by Professor Steven LoBello at Auburn University at Montgomery, asked their participants to complete a questionnaire about their depression symptoms over the previous two weeks. Crucially, the participants all completed the survey at different times of the year, allowing the researchers to look for any seasonal patterns.
由奥本大学（位于蒙哥马利）的Steven LoBello教授带领的研究人员要求参与者填写一份关于他们近两周抑郁症状的调查问卷。至关重要的是，所有参与者都在当年不同时期完成调查，这让研究人员能够在其中寻找季节性规律。
Contrary to what you might think, the results provided no evidence whatsoever that people’s depression symptoms tended to be higher in winter — or at any other time of the year. This lack of a seasonal effect was true whether looking at the entire sample or only respondents with depressive symptoms. The respondents’ geographical latitude and sunlight exposure on the day of the survey were also unrelated to depression scores.
可能与你的预期不同，研究结果并没有为“人们的抑郁症状在冬季（或一年中任何其他时间）更明显”这种说法提供任何支持证据。无论是根据全部样本，还是仅考虑拥有抑郁症状的受访者，这种季节性影响的缺失都成立。调查当天受访者所处的地理纬度和接受的光照量同样与抑郁指数无关。
The researchers are clear about what this means for what they call the “well-entrenched folk theory” that winter brings on or worsens depression. Their results, they write, “cast serious doubt on major depression with seasonal variation as a legitimate psychiatric disorder.”
研究者很清楚，这项结果对于他们所谓的“根深蒂固的民间理论”所认为的冬季能带来或加重抑郁症的说法意味着什么；他们认为这项研究成果“严重质疑了将‘与季节有关的重性抑郁’认定为一种精神疾病的合理性。”
They think the early studies on the concept of SAD were flawed by virtue of the fact that they selectively recruited people who said they suffered from winter-related mood changes — an approach that was likely susceptible to confirmation bias, or selectively interpreting evidence to support a theory you already have.
他们认为，关于SAD概念的早期研究错在选择性地招募认为自己正在遭受冬季相关的情绪变化的人——这种方法很容易受确认偏误的影响，还容易使研究者通对证据的选择性解释去支持自己已有的理论。
This makes intuitive sense. Once the concept of SAD was introduced, after all, it captured the public imagination and went on to spawn a whole industry based around ways to treat the “condition,” including using artificial light.
这一质疑在直觉上说得过去。毕竟，一旦SAD概念被引入，它就抓住了公众的想象力，继而催生了基于治疗这种“病症”的方法（包括利用人工光照）的整个产业。
In spite of the sketchy evidence for SAD, once it was accepted that the dark months affect our mood, it was only a small step to assuming that they probably have an adverse effect on our cognition, too — hence the internet now being full of articles on how to beat that winter sluggishness.
尽管SAD的证据质量较差，人们一旦接受“灰暗的月份会影响我们心情”这种看法，离假设冬季对我们的认知也可能有不良影响也就不远了——因此，互联网上充斥着有关“如何打败冬日倦怠”的文章。
But this idea, too, is challenged by a new piece of research. That paper, published in Proceedings of the National Academy of Sciences, looked at whether the time of year affects basic brain function. It’s one of the first studies to do so, and, like the depression-scores study, it seems to refute a common cultural understanding of the effects of cold, dark days.
但是一项新研究同样挑战了这个想法。这篇论文发表在《美国国家科学院院刊》，它就“年度时段是否会影响大脑功能”做了考察。这是最早涉猎该主题的研究之一，与前文中抑郁评分研究一样，这项研究成果似乎反驳了大众文化对于黑暗寒冷的日子所带来影响的理解。
The neuroscientists, led by Christelle Meyer at the University of Liège in Belgium, recruited 28 young men and women at different times of year to answer questions about their mood, emotions, and alertness; have their melatonin (a hormone that regulates the sleep cycle) levels measured; and complete two psychology tasks in a brain scanner.
由比利时Liège大学Christelle Meyer带领的神经科学家团队在一年中的不同时间招募了28名青年男女去回答关于自己心情、情绪和警觉性的问题；测试他们的褪黑激素（一种调节睡眠周期的激素）水平；并让他们在大脑扫描仪中完成两项心理任务。
One task was a test of vigilance and involved pressing a button as fast as possible whenever a stopwatch appeared at random intervals on-screen, and the other was a test of working memory, which involved listening to streams of letters and spotting when the current letter was the same as the one presented three items earlier. The basic idea was to see if the participants’ brain activity during these tasks was different depending on the season.
一项是警觉性测试，包括当屏幕上以随机时间间隔出现秒表时尽可能快地按按钮。另一项是工作记忆测试，包括听一连串字母，并认出和三个之前展示的字母一样的当前字母。该研究的基本宗旨是考察参与者在这些任务中的大脑活动是否会根据季节而不同。
The participants’ feelings of alertness, their emotional state, and melatonin levels mostly didn’t vary with the seasons, and they actually performed equally well on both tasks in the scanner regardless of the time of year, thus undermining the idea that the winter has an adverse effect on our mental abilities (more on this shortly).
参与者的警觉感、情绪状态、以及褪黑激素水平基本没有随季节而变化，而且实际上无论在一年中的什么时间，他们在两项于扫描仪中完成的任务里表现同样好，由此削弱了冬季会给我们的心理能力带来不利影响的想法。
One question on mood did show some seasonal variation, but participants’ moods were lowest in the fall, not winter. In terms of underlying brain function, participants’ neural activity was highest during the memory task for those participants tested in spring and lowest for those tested in the fall, so, far from being a special case, winter brain activity sat in the middle.
在关于情绪的其中一个问题上，数据确实表现出一定的季节性变化，但是参与者的情绪最低点在秋季，而不是冬季。在相应的大脑功能方面，记忆测试中，春季接受测试的参与者的神经活动最高，秋季接受测试者的神经活动最低。因此，冬天的大脑活动处于中间水平，并不特别。
Meanwhile, during the vigilance task, brain activity was lowest in the winter and highest in the summer. Some media outlets have interpreted this as evidence for winter sluggishness, but as the participants’ performance and alertness was as good in winter as at other times of year, their reduced winter brain activity can actually be seen as a sign of improved efficiency. For comparison, consider research showing how the more expert people become at a task, the less brain activity is seen while they perform that task, as the brain becomes more efficient.
同时，在警觉性测试中，大脑活动水平在冬季最低，夏季最高。一些媒体把这解释为冬季倦怠的证据，但是参与者在冬季的表现与警觉性和一年中其他时间一样好，他们减弱的冬季大脑活动可以看成是效率提高的一个标志。为了进行比较，请考虑另一些研究，它们揭示了，随着人们在任务中变得更专业，大脑执行该任务的效率提高，执行任务时的大脑活动会变得更低。
You could even think of this reduced winter neural activity as your brain entering a kind of “eco mode,” allowing it to perform as well as it does in summer but while consuming fewer resources. This makes sense from an evolutionary perspective: When resources are scarce and the weather is harsh, it’s obviously advantageous that the brain should be capable of performing basic tasks, especially those involving vigilance, in an economic fashion. (I should note that this is my interpretation — the researchers remain relatively neutral about the meaning of the seasonal effects they observed, and didn’t return an email I sent them inquiring about what those effects might mean.)
你甚至可以把这种冬季减弱的神经活动看成是大脑进入了一种“经济模式”，允许其和在夏天表现得一样好但同时消耗更少的资源。这从进化的角度来看说得通：当资源稀缺，天气恶劣时，如果大脑能以一种经济节能的方式执行基本任务，特别是涉及警觉性的任务，显然是有利生存的。（我有必要指出，这是我自己的解释——研究者对他们观察到的季节性影响的含义保持相对中立，并且没有回复我发给他们的质询这些影响背后意义的邮件。）
This suggestion that our mental function might actually be enhanced in winter is actually backed up by a (frequently ignored) study published in the late 1990s in Applied Cognitive Psychology. Researchers at the University of Tromsø in Norway tested 62 participants on a range of mental tasks in winter and again in summer (some completed them in winter first, the others in summer, thus balancing out any practice effects).
我们的心理功能实际上有可能会在冬季增强这一看法，事实上还被1990年代末发表在《应用认知心理学》的一项（经常被忽视的）研究支持。挪威特罗姆斯大学的研究者测试了62名参与者在冬季和夏季的一系列心理测试（一部分参与者先在冬天完成，其余参与者在夏季完成，因此排除任何练习效应）。
This was just about the perfect setting for such a study, since the contrasts were so extreme: Tromsø is located more than 180 miles north of the Arctic Circle, meaning there is virtually no sunlight in Tromsø during the winter and no darkness in the summer.
对于此种研究这是一个完美的设定，因为对比是如此极端：特罗姆斯位于北极圈以北180多公里，这意味着实际上特罗姆斯的冬季几乎没有阳光，夏季几乎没有黑暗。
Across the battery of tests, the researchers found little evidence of seasonal effects, but those they did find were largely in favor of a winter advantage. In winter, participants performed better on two different tests of reaction time, and they showed evidence of enhanced mental control on the well-established Stroop test that involves naming color words while ignoring the ink color they are written in. Only one test showed a slight summer advantage, and that was for verbal fluency.
在一系列测试中，研究者只发现了很少有关季节性影响的证据，但是只要是他们是他们找到了的，大部分有利于冬季优势。在冬季，参与者在两项不同的反应时间测试中表现更好，并且在著名的斯特鲁测试中，涉及到报出颜色词汇而忽略写下它们所用的墨水颜色，他们表现出精神控制增强的证据。只有一个测试显示了轻微的夏季优势，那是涉及语言流利性的。
Summing up their findings, Dr. Tim Brennan and his colleagues wrote that “despite the subjective feeling one may have that one is mentally sluggish in winter, our data do not lend empirical support to the intuitive claim.”
总结他们的发现时，提姆布伦南博士和他的同事们写道：“尽管主观感觉一个人或许在冬季精神上会倦怠，我们的数据却并没有为这种直觉断言提供经验支持。”
Many people dislike winter for obvious reasons, and the idea that these darker months make many of us profoundly miserable and cognitively impaired fits a narrative about this being a difficult time of year (as Adam Gopnik wrote, “one of the most natural metaphors we make is of winter as a time of abandonment and retreat. The oldest metaphors for winter are all metaphors of loss”).
很多人出于显而易见的理由不喜欢冬季，人们认为这些阴暗的月份让许多人极度痛苦、认知受损，这种想法迎合了关于这一年度艰难时期的一段描述——亚当·戈普尼克写道，“我们最自然的隐喻之一是将冬季比作放弃和退缩的时期。而且关于冬季最古老的隐喻全都关乎失去。”
But we should be cognizant of how our expectations shape the way we experience the world — it may be the case that, after hearing over and over and over that winter slows us down, making us more sluggish and sad, we interpret days when we’re feeling down for other reasons as proof that it’s winter’s fault.
但我们应该认识到，我们的期望会塑造我们体验世界的方式——以下状况是可能的：当一遍又一遍听到冬季会使人迟钝，让我们变得倦怠和悲伤时，我们会把自己因其他原因感到沮丧的事例归罪于冬季。
Sure, the winter presents us with many practical challenges, like coping with colds and flu and getting to work through the snow, but what these new studies suggest is that the season doesn’t have some mystical, malevolent effect on our brains. If anything, the data suggest that our minds are more sprightly at this time of year than in the summer. Now there’s some news to brighten your day — even if it’s an abysmally cold, short one.
当然，冬季会给我们带来很多实际的挑战，比如应对感冒和流感、穿过雪地去上班，但是这些最新研究显示，冬季并不会对我们的大脑有神秘的、恶毒的影响。如果说有影响，这些数据显示我们的思维在每年这个时候比起夏季更加活跃。现在总算有了些好消息来照亮你的日子——即使是一个极冷极短的冬日。
翻译：董慧颖
校对：斑马（@鹿兔马朦）
编辑：辉格@whigzhou