Does stress affect your memory? - Elizabeth Cox

譯者: Lilian Chiu 審譯者: Helen Chang

You spend weeks studying for an important test.

你花了數週的時間 準備一個重要的考試。

On the big day, you wait nervously as your teacher hands it out.

在這個大日子，你緊張地 等著你的老師發考卷，

You’re working your way through, when you’re asked to define ‘ataraxia.’

當你開始考試時，你碰到一個問題 是要你定義「心神安寧」。

You know you’ve seen it before, but your mind goes blank.

你知道你之前看過這個詞， 但你的腦中一片空白。

What just happened?

發生了什麼事？

The answer lies in the complex relationship

答案和壓力與記憶

between stress and memory.

之間的關係有關。

There are many types and degrees of stress

壓力有不同的類型和程度，

and different kinds of memory,

記憶也有不同種類，

but we’re going to focus on how short-term stress

但我們要把焦點放在短期的壓力

impacts your memory for facts.

如何影響你對於事實的記憶。

To start, it helps to understand how this kind of memory works.

先了解一下這種記憶如何運作 是會有幫助的。

Facts you read, hear, or study

你讀到、聽到，或研究到的事實

become memories through a process with three main steps.

會透過一個過程變成記憶， 這個過程有三個主要步驟。

First comes acquisition:

一開始是「取得」：

the moment you encounter a new piece of information.

也就是你接觸到 新資訊的那個時刻，

Each sensory experience activates a unique set of brain areas.

每一種感官經驗所啟動的 大腦區域都是獨一無二的。

In order to become lasting memories,

若要成為能持續下去的記憶，

these sensory experiences

這些感官經驗

have to be consolidated by the hippocampus,

就需要被海馬迴給強化，

influenced by the amygdala,

會受到杏仁核的影響，

which emphasizes experiences associated with strong emotions.

杏仁核所著重的是 和強烈情緒有關的經驗。

The hippocampus then encodes memories,

接著，海馬迴會把記憶編碼，

probably by strengthening the synaptic connections

做法可能是將原始感官經驗過程中

stimulated during the original sensory experience.

所促成的突觸連結給強化。

Once a memory has been encoded,

一旦記憶被編碼了之後，

it can be remembered, or retrieved, later.

它就能被記住，之後也能再取用它。

Memories are stored all over the brain,

記憶儲存在大腦各處，

and it’s likely the prefrontal cortex that signals for their retrieval.

要求取回記憶的訊息 可能是由前額葉皮質負責。

So how does stress affect each of these stages?

所以，壓力如何影響每一個階段？

In the first two stages,

在前兩個階段，

moderate stress can actually help experiences enter your memory.

中度的壓力其實可以 幫助經驗進入你的記憶。

Your brain responds to stressful stimuli

對於有壓力的刺激， 你的大腦的反應會是

by releasing hormones known as corticosteroids,

釋放出一種叫做 糖皮質激素的荷爾蒙，

which activate a process of threat-detection

它會啟動杏仁核中一個偵測威脅

and threat-response in the amygdala.

並做出反應的過程。

The amygdala prompts your hippocampus

杏仁核會提示海馬迴

to consolidate the stress-inducing experience into a memory.

強化造成壓力的經驗， 讓它進入記憶中。

Meanwhile, the flood of corticosteroids from stress

同時，因為壓力所產生的 大量糖皮質激素

stimulates your hippocampus,

會刺激你的海馬迴，

also prompting memory consolidation.

亦會促進記憶強化。

But even though some stress can be helpful,

但，雖然有一點壓力是有幫助的，

extreme and chronic stress can have the opposite effect.

極端和長期的壓力 可能會有相反效果。

Researchers have tested this by injecting rats directly with stress hormones.

研究者測試這個想法的方式，是將 壓力荷爾蒙直接注射到老鼠體內。

As they gradually increased the dose of corticosteroids,

當他們漸漸增加 糖皮質激素的劑量時，

the rats’ performance on memory tests increased at first,

老鼠在記憶測驗上的表現 一開始是提升的，

but dropped off at higher doses.

但在更高劑量時就下降了。

In humans, we see a similar positive effect with moderate stress.

在人類身上，有中度壓力時， 我們看到類似的正向影響。

But that only appears when the stress is related to the memory task—

但只有在壓力是與記憶工作任務 有關時才會有這個現象——

so while time pressure might help you memorize a list,

所以，雖然時間壓力可能 可以協助你記住一張清單，

having a friend scare you will not.

但要朋友來嚇你 造成的壓力就沒有幫助。

And the weeks, months, or even years

若長期壓力造成糖皮質激素

of sustained corticosteroids that result from chronic stress

維持數週、數月，甚至數年之久，

can damage the hippocampus

海馬迴可能會受損，

and decrease your ability to form new memories.

你形成新記憶的能力 也可能會下降。

It would be nice if some stress also helped us remember facts,

如果承受一些壓力能夠協助我們 記住事實，那是好事，

but unfortunately, the opposite is true.

但，不幸的是，反之亦然。

The act of remembering relies on the prefrontal cortex,

「記住」這個動作 要仰賴前額葉皮質，

which governs thought, attention, and reasoning.

前額葉皮質掌管思想、 注意力，和推理。

When corticosteroids stimulate the amygdala,

當糖皮質激素刺激了杏仁核，

the amygdala inhibits, or lessens the activity of,

杏仁核就會抑制或減少

the prefrontal cortex.

前額葉皮質的活動。

The reason for this inhibition is so the fight/flight/freeze response

會發生抑制，是因為這麼一來， 戰鬥／逃跑／不動的反應

can overrule slower, more reasoned thought in a dangerous situation.

就能在危險的情境中壓過 比較緩慢、經過推論的思維。

But that can also have the unfortunate effect

但那也可能會有不利的影響，

of making your mind go blank during a test.

讓你的大腦在考試時一片空白。

And then the act of trying to remember can itself be a stressor,

接著，「試圖記起來」這個行為 本身就可能會是個壓力源，

leading to a vicious cycle of more corticosteroid release

導致惡性循環， 釋放更多的糖皮質激素，

and an even smaller chance of remembering.

能記起來的機會就更小了。

So what can you do to turn stress to your advantage

你要怎麼做，才能 把壓力轉成你的優勢，

and stay calm and collected when it matters the most?

並在最要緊的時刻 保持冷靜和鎮定？

First, if you know a stressful situation like a test is coming,

首先，如果你知道一個很有壓力的 情境即將到來，比如考試要到了，

try preparing in conditions similar to the stressful environment.

試著在和壓力環境 類似的條件之下做準備。

Novelty can be a stressor.

新奇性可能是個壓力源。

Completing practice questions under time pressure,

在時間壓力之下做完練習題，

or seated at a desk rather than on a couch,

或是坐在書桌前而不是沙發上，

can make your stress response to these circumstances

都能讓你在真正考試時，

less sensitive during the test itself.

對這些情況的反應比較不敏感。

Exercise is another useful tool.

另一項很有用的工具就是運動。

Increasing your heart and breathing rate

增加你的心跳率和呼吸率

is linked to chemical changes in your brain

會造成你的大腦中產生化學改變，

that help reduce anxiety and increase your sense of well-being.

協助減少焦慮，並增加你的幸福感。

Regular exercise is also widely thought to improve sleeping patterns,

定時運動也被廣泛認為 可以改善睡眠模式，

which comes in handy the night before a test.

考試的前一晚能派上用場。

And on the actual test day,

到了考試的那一天，

try taking deep breaths to counteract your body’s flight/fight/freeze response.

試著深呼吸，來對抗你身體的 戰鬥／逃跑／不動反應。

Deep breathing exercises have shown measurable reduction in test anxiety

研究顯示，深呼吸運動能 大大減少在考試時的焦慮，

in groups ranging from third graders to nursing students.

研究對象範圍從三年級生 到護理學生都有。

So the next time you find your mind going blank at a critical moment,

所以，下次當你發現你的大腦 在關鍵時刻一片空白時，

take a few deep breaths until you remember ataraxia:

做幾次深呼吸， 直到你記起「心神安寧」，

a state of calmness, free from anxiety.

定義為：一種冷靜、 沒有焦慮的狀態。