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Think back to a really vivid memory.
請試著回想一個鮮明的回憶。
Got it?
想到了嗎?
Okay, now try to remember what you had for lunch three weeks ago.
現在試著回想你三個禮拜前的午餐吃了些什麼。
That second memory probably isn't as strong. But why not?
這記憶可能沒有那麼深刻,但為何不呢?
Why do we remember some things and not others?
為什麼我們會記得某些東西而忘記其他的呢?
And why do memories eventually fade?
以及為何我們的記憶最終會淡去?
Let's look at how memories form in the first place.
讓我們來看看記憶究竟是如何形成的。
When you experience something, like dialing a phone number, the experience is converted into a pulse of electrical energy that zips along a network of neurons.
當你經歷了某件事情,像是播個電話號碼,這經歷會轉換為一束電子脈衝並沿著神經元網絡傳遞。
Information first lands in short-term memory, where it's available from anywhere from a few seconds to a couple of minutes.
訊息會首先到達短期記憶,可能從幾秒到幾分鐘都有。
It's then transferred to long-term memory through areas such as the hippocampus, and finally to several storage regions across the brain.
然後再經過海馬迴等其他區域後,被傳送到長期記憶區最後傳到大腦內的數個儲存區域。
Neurons throughout the brain communicate at dedicated sites called synapses, using specialized neurotransmitters.
分散在大腦裡的神經元在稱為突觸的特定區域以專門的神經傳導物質來交換訊息。
If two neurons communicate repeatedly, a remarkable thing happens:
如果兩個神經元持續地傳遞訊息,會有驚奇的事發生:
The efficiency of communication between them increases.
那就是這兩個神經元的溝通效率會提高。
This process, called long term potentiation, is considered to be a mechanism by which memories are stored long-term.
這個過程我們稱之為長期增強作用,也是這個機制使我們大腦儲存了長期記憶,
But how do some memories get lost?
但是為何有些記憶會不見呢?
Age is one factor.
年齡是一個因素。
As we get older, synapses begin to falter and weaken, affecting how easily we can retrieve memories.
當我們年紀越大,突觸開始衰弱退化影響我們回想記憶的難易度。
Scientists have several theories about what's behind this deterioration.
對於這個退化過程的原因,科學家有幾種不同的理論,
From actual brain shrinkage⏤the hippocampus loses 5% of its neurons every decade, for a total loss of 20% by the time you're 80 years old⏤to the drop in the production of neurotransmitters, like acetylcholine, which is vital to learning and memory.
從實際大腦萎縮的程度,海馬迴每十年便會失去 5% 的神經元到你 80 歲的時候,總損失可達到 20% 。到神經傳遞物質製造的衰退像是對學習與記憶能力重要的乙醯膽鹼。
These changes seem to affect how people retrieve stored information.
這些改變可能會影響到人們如何想起儲存的資訊。
Age also affects our memory-making abilities.
年齡也會影響我們創造記憶的能力。
Memories are encoded most strongly when we're paying attention, when we're deeply engaged, and when information is meaningful to us.
當我們重視某樣東西時,對它才會印象深刻,譬如當我們投入其中、或其資訊對我們來說意義深遠時。
Mental and physical health problems, which tend to increase as we age, interfere with our ability to pay attention, and thus act as memory thieves.
隨著年齡遞增,我們心靈及身體上的健康問題可能也隨之增加,進而影響我們的注意力像個記憶小偷。
Another leading cause of memory problems is chronic stress.
另外一個主要原因是長期性的壓力。
When we're constantly overloaded with work and personal responsibilites, our bodies are on hyper-alert.
當我們不堪工作及個人責任的負荷時我們的身體會過度警戒。
This response has evolved from the physiological mechanism designed to make sure we can survive in a crisis.
這反應是由生理機制演化而來的為了確保我們遇到危機時能夠存活。
Stress chemicals help mobilize energy and increase alertness.
壓力化學物質能夠幫助傳輸能量及增加警覺性。
However, with chronic stress, our bodies become flooded with these chemicals, resulting in a loss of brain cells and an inability to form new ones, which affects our ability to retain new information.
不過當我們承受長期壓力時,我們的身體會充滿了這些化學物質,並會導致腦細胞的損壞及降低新腦細胞的製造能力, 進而導致影響我們記憶資訊的能力。
Depression is another culprit.
憂鬱則是另外一個罪魁禍首。
People who are depressed are 40% more likely to develop memory problems.
受到憂鬱困擾的人們比一般人高出 40% 的機率會有記憶問題。
Low levels of serotonin, a neurotransmitter connected to arousal, may make depressed individuals less attentive to new information.
當作為與感知能力間的傳遞物質:血清素的含量過低時,會導致憂鬱的人們對新資訊注意力降低。
Dwelling on sad events in the past⏤another symptom of depression⏤makes it difficult to pay attention to the present, affecting the ability to store short-term memories.
另外一個憂鬱的症狀是對於過去的傷心往事無法忘懷,這使人對當下發生的事注意力不集中進而影響短期記憶能力。
Isolation, which is tied to depression, is another memory thief.
另外一個記憶的小偷,便是跟憂鬱緊緊相關的孤立感。
A study by the Harvard School of Public Health found that older people with high levels of social integration had a slower rate of memory decline over a six-year period.
哈佛公共衛生學院的一份研究指出在六年的區間內,越融入社會的老年人,他們記憶衰退的速度會越緩慢。
The exact reason remains unclear, but experts suspect that social interaction gives our brain a mental workout.
雖然仍不確定原因是什麼但專家們推測 融入社會能訓練我們的大腦。
Just like muscle strength, we have to use our brain or risk losing it.
就像訓練肌肉一樣若不頻繁使用,機能便會退化。
But don't despair.
但你也別太過擔心。
There are several steps you can take to aid your brain in preserving your memories.
這裡有些步驟可以幫你留住你的記憶。
Make sure you keep physically active.
務必常常活動你的身體。
Increased blood flow to the brain is helpful.
增加流入大腦的血量是有幫助的。
And eat well.
然後吃好。
Your brain needs all the right nutrients to keep functioning correctly.
你的大腦需要各種正確的營養素來保持運作。
And finally, give your brain a workout.
最後,你也要訓練你的大腦。
Exposing your brain to challenges like learning a new language is one of the best defenses for keeping your memories intact.
給你的大腦一些挑戰,例如學習一個新語言便是保衛記憶完整的一個最佳方法。