You spend weeks studying for an important test.
你花了好几周时间准备一场重要的考试。
On the big day, you wait nervously as your teacher hands it out.
考试当天，你紧张地等待老师分发试题。
You're working your way through, when you're asked to define 'ataraxia.'
你努力作答，看到一道题目要求解释“ataraxia”。
You know you've seen it before, but your mind goes blank. What just happened?
你记得自己曾见过这个词，但是大脑却一片空白。这是怎么回事？
The answer lies in the complex relationship between stress and memory.
答案在于压力与记忆之间存在复杂的联系。
There are many types and degrees of stress and different kinds of memory,
压力的类型和程度多种多样，记忆也是如此，
but we're going to focus on how short-term stress impacts your memory for facts.
但我们将集中探讨短期压力如何影响内容记忆。
To start, it helps to understand how this kind of memory works.
首先，我们先来理解这类记忆是如何工作的。
Facts you read, hear, or study become memories through a process with three main steps.
你读到、听到或学到的事实会经过三个主要步骤成为记忆。
First comes acquisition: the moment you encounter a new piece of information.
首先是信息获取，即获得新的信息。
Each sensory experience activates a unique set of brain areas.
每种感官体验都会激活大脑特定的区域。
In order to become lasting memories, these sensory experiences have to be consolidated by the hippocampus,
为了形成长期记忆，这些感官体验会经海马体进行增强，
influenced by the amygdala, which emphasizes experiences associated with strong emotions.
并受到杏仁核的影响，杏仁核能够强化带有强烈情感的经验。
The hippocampus then encodes memories, probably by strengthening the synaptic connections stimulated during the original sensory experience.
在这之后，海马体对记忆进行编码方法可能是通过加强感官体验发生时建立的突触连接。
Once a memory has been encoded, it can be remembered, or retrieved, later.
一旦记忆被编码，它能够在之后被记住和提取。
Memories are stored all over the brain, and it's likely the prefrontal cortex that signals for their retrieval.
记忆存储区遍布大脑，很可能是由前额叶负责发出提取记忆的信号。
So how does stress affect each of these stages?
那么压力是如何影响这个过程的呢？
In the first two stages, moderate stress can actually help experiences enter your memory.
在前两个阶段，适度的压力实际上可以帮助感官体验进入记忆。
Your brain responds to stressful stimuli by releasing hormones known as corticosteroids,
你的大脑会对压力刺激做出反应，释放出皮质类固醇激素，
which activate a process of threat-detection and threat-response in the amygdala.
这会激活杏仁核中的威胁感知和威胁应对程序。
The amygdala prompts your hippocampus to consolidate the stress-inducing experience into a memory.
杏仁核会促使海马体加强压力引发的经验进入记忆。
Meanwhile, the flood of corticosteroids from stress stimulates your hippocampus, also prompting memory consolidation.
同时压力导致皮质类固醇大量分泌，进一步刺激海马体，有助于记忆巩固。
But even though some stress can be helpful, extreme and chronic stress can have the opposite effect.
即便有些压力是有用的，压力过大或长期压力都会适得其反。
Researchers have tested this by injecting rats directly with stress hormones.
研究者向老鼠直接注射压力激素进行了实验。
As they gradually increased the dose of corticosteroids,
随着皮质类固醇的剂量不断增加，
the rats' performance on memory tests increased at first, but dropped off at higher doses.
老鼠在记忆方面的表现先是增高，之后便随剂量继续增加而下降。
In humans, we see a similar positive effect with moderate stress.
对于人类而言，适度压力起到了相似的积极作用。
But that only appears when the stress is related to the memory task
但是这只表现在与记忆相关的压力上，
so while time pressure might help you memorize a list, having a friend scare you will not.
因此时间压力虽然能帮你提高记忆，但来自朋友的惊吓则没有这种效果。

And the weeks, months, or even years of sustained corticosteroids that result from chronic stress
慢性压力会带来的长达数周、数月甚至数年的皮质类固醇的持续分泌，
can damage the hippocampus and decrease your ability to form new memories.
会对海马体造成伤害，并且削弱形成新记忆的能力。
It would be nice if some stress also helped us remember facts, but unfortunately, the opposite is true.
如果压力能帮助记忆就好了，遗憾的是，事实恰恰相反。
The act of remembering relies on the prefrontal cortex, which governs thought, attention, and reasoning.
记忆行为依赖前额叶，它控制着思考，注意力和推理能力。
When corticosteroids stimulate the amygdala, the amygdala inhibits, or lessens the activity of, the prefrontal cortex.
当皮质类固醇刺激杏仁核，杏仁核会抑制或是减少前额叶的活动。
The reason for this inhibition is so the fight/flight/freeze response can overrule slower, more reasoned thought in a dangerous situation.
原因在于，在危险环境下，逃跑/战斗的应激反应优于速度更慢，需要推理的思考过程。
But that can also have the unfortunate effect of making your mind go blank during a test.
但这也带来了不好的影响，它会让你的大脑在考试时一片空白。
And then the act of trying to remember can itself be a stressor,
尝试回忆会进一步产生压力，
leading to a vicious cycle of more corticosteroid release and an even smaller chance of remembering.
从而导致分泌更多皮质类固醇，形成恶性循环，这让想起答案的几率变得更小。
So what can you do to turn stress to your advantage and stay calm and collected when it matters the most?
那么该如何让压力为你所用，如何在最重要的时刻保持镇定和冷静？
First, if you know a stressful situation like a test is coming, try preparing in conditions similar to the stressful environment.
首先，如果你了解压力情境，例如即将到来的考试，你可以模拟相似的压力环境做好准备。
Novelty can be a stressor. Completing practice questions under time pressure, or seated at a desk rather than on a couch,
新鲜体验可能是一项压力来源。在时间限制下完成练习题目，或是坐在桌旁学习而不是沙发上，
can make your stress response to these circumstances less sensitive during the test itself.
都可以让你在考试时对这些压力的敏感性降低。
Exercise is another useful tool. Increasing your heart and breathing rate is linked to chemical changes in your brain
体育锻炼也很有用。提高心跳和呼吸频率会改变大脑中的化学物质，
that help reduce anxiety and increase your sense of well-being.
这能帮助你减少焦虑，提高幸福感。
Regular exercise is also widely thought to improve sleeping patterns, which comes in handy the night before a test.
规律的锻炼也被广泛认为能改善睡眠，好的睡眠在考前一晚非常重要。
And on the actual test day, try taking deep breaths to counteract your body's flight/fight/freeze response.
到了考试当天，试着做深呼吸来平衡身体的应激反应。
Deep breathing exercises have shown measurable reduction in test anxiety in groups ranging from third graders to nursing students.
实验对象从三年级学生到护理专业学生的一项实验证实，深呼吸能有效减少考试焦虑。
So the next time you find your mind going blank at a critical moment,
所以在下一次重要时刻大脑一片空白时，
take a few deep breaths until you remember ataraxia: a state of calmness, free from anxiety.
做几次深呼吸，直到你想起来ataraxia是什么意思：一种平静的、没有焦虑情绪的状态。