什麼是既視感（Déjà vu）？：英語精讀講義

Hey Vsauce, Michael here and today we're going to discuss déjà vu.

嗨，Vsauce，我是 Michael，今天我們要來聊聊既視感。

What is it and why does it occur?

它是什麼，又為什麼會發生？

You know, those moments where the current situation feels like it's happened before. 片語搭配

你知道，就是那種覺得眼前情況以前發生過的時刻。

You're certain it has, but you don't know when or how it became so familiar.

你確信它發生過，卻不知道是什麼時候，也不知道它為何會如此熟悉。

It's difficult to scientifically study déjà vu because there's no reliable way to cause it to happen in people's heads in a laboratory.

要用科學方法研究既視感很困難，因為在實驗室裡，沒有可靠的方法能讓這種感覺出現在人的腦海中。

But here's what we do know. 表達脈絡

不過，下面這些是我們確實知道的。

Humans don't seem to experience déjà vu until they're at least 8 or 9 years old.

人類似乎至少要到 8、9 歲才會體驗到既視感。

It's most frequent in your teens and 20s and then tapers off as you get older. 片語動詞

它在十幾歲和二十多歲時最常見，之後會隨著年齡增長逐漸減少。

So it might have something to do with brain development. 片語搭配

所以，它或許與大腦發育有關。

In fact, we should probably go get ourselves a brain.

其實，我們或許該去弄顆大腦來。

That was easy.

真輕鬆。

Now, like a stomach ache, déjà vu may be a symptom with many possible causes.

既視感就像胃痛一樣，可能是一種症狀，背後有許多可能的成因。

A lot of the popular theories about what causes it involve

關於既視感為何會發生，許多流行理論都認為，問題出在

a disconnect that may be occurring between the deep structures of the brain that process our experiences unconsciously

無意識處理我們經歷的大腦深層結構

and the parts of the brain that are conscious of what we experience, process it, and then tell us what we're seeing.

與有意識地感知和處理經歷、再告訴我們看到了什麼的大腦區域之間可能出現了脫節。

For the sake of simplicity, let's begin with the visual system. 片語搭配

為了簡單起見，我們先從視覺系統說起。

Now, the brain sits in your head like this and your eyeballs are over here seeing things,

大腦像這樣待在你的腦袋裡，而眼球在這邊看東西，

sending that signal to the back of the brain, the occipital lobe, where visual cortex is.

再把訊號傳到大腦後方的枕葉，也就是視覺皮質所在的位置。

That's where the image is processed and we become aware of what we're seeing.

影像就是在那裡受到處理，我們也因此意識到自己看見了什麼。

But visual cortex isn't the first stop that information makes. 慣用語

但視覺皮質並不是這些資訊抵達的第一站。

Instead, we know that it stops in lots of other places.

我們知道，資訊其實還會經過許多其他地方。

For instance, the amygdala, where it may be processed at an involuntary emotional level.

比如杏仁核，資訊可能會在那裡從不由自主的情緒層面受到處理。

And this fun little part right here, number 31, the tectum.

還有這裡這個有趣的小部位，31 號，也就是頂蓋。

It's involved in preliminary visual processing and helps control eye movements.

它參與初步的視覺處理，也有助於控制眼球運動。

Now that fact is incredibly important

這一點極其重要，

because what it means is that people with blindness caused by brain damage to the visual cortex cannot see anything. 文法

因為這表示，因視覺皮質受損而失明的人什麼都看不見。

They don't report seeing or recognizing anything.

他們不會表示自己看見或認出了任何東西。

However, the other preliminary parts of the brain that get that message are still healthy.

然而，大腦中其他接收該訊號、負責初步處理的部位仍然健全。

And so, despite being legally blind, these people exhibit what is known as blindsight. 文化背景

因此，這些人儘管在法律上被認定為失明，卻會表現出所謂的「盲視」。

They can defy all odds and avoid an obstacle course on the ground. 慣用語

他們甚至能出人意料地避開設置在地面上的一連串障礙物。

They can also be presented faces showing joy or anxiety and fear

還可以讓他們看表現出喜悅、焦慮或恐懼的臉孔，

and feel without knowing why at all on Earth they feel that way a similar emotion.

而他們會產生類似的情緒，卻完全不知道自己究竟為何有這種感覺。

So a lot is going on when we look at things. 片語動詞

所以，我們看東西時，大腦其實在進行很多活動。

And if those preliminary structures in the vision system allow certain blind people to be oddly and unconsciously aware of what they're looking at,

如果視覺系統中的這些初步處理結構，能讓某些盲人以一種奇特而無意識的方式察覺自己所看的東西，

we may have the ingredients we need for this disconnect.

那麼，我們或許就有了產生這種脫節所需的要素。

Think of it this way. 表達脈絡

可以這樣理解。

If I experience event A and then B and then C

假設我依序經歷了事件 A、B 和 C，

and the inner parts of my brain commit it to memory and generate an emotional response, 片語搭配

大腦內部區域把它們存進記憶，並產生情緒反應，

but then a fraction of a second later out of sync, 講解

但晚了幾分之一秒，時間上沒有同步，

my visual cortex finally gets around to telling me, the conscious aware part of my brain, what I'm seeing, 片語動詞

我的視覺皮質才終於把我看到的東西告訴「我」，也就是大腦中有意識、有覺知的部分，

it'll say, "Okay guys,

它會說：「好了，各位，

we're looking at A and then B and then"

我們看到的是 A，然後是 B，接著是——」

and the brain says, "Woah, woah, woah.

大腦卻說：「哇、哇、哇。

Wait, wait.

等等，等等。

And then C, right?

接下來是 C，對吧？

I mean, it's already happened,

我是說，這明明已經發生過了，

I thought. Wait, wait."

我剛才就這麼覺得。等等，等等。」

And that may be déjà vu.

這或許就是既視感。

But what could cause these processes dealing with the same information to get temporarily out of sync like that?

但處理同一資訊的這些過程，為什麼會像這樣暫時失去同步呢？

Well, it's probably a neurological abnormality,

嗯，很可能是某種神經系統異常，

possibly an epileptic episode where neurons all fire in sync. 用詞

也可能是一次所有神經元同步放電的癲癇發作。

We also know that patients who experience chronic and persistent déjà vu tend to have brain damage in the temporal lobes of their brain. 文法

我們還知道，長期持續出現既視感的患者，其大腦顳葉往往有損傷。

These lobes on either side.

就是兩側的這兩個腦葉。

Well, that sounds kind of bad, right? 語氣意圖

聽起來有點糟，對吧？

I mean, when I experience déjà vu, should I run to the doctor right away? 片語搭配

那我一有既視感，是不是就該立刻跑去看醫生？

Well, not at all. 語氣意圖

完全不用。

In fact, minor epileptic events are quite common.

其實，輕微的癲癇性活動相當常見。

You've probably experienced a similar phenomenon known as a hypnagogic jerk. 文化背景

你很可能體驗過一種類似的現象，稱為入睡抽動。

That's a fancy name for what occurs when you're about to fall asleep 講解

這是一個聽起來很專業的名稱，指的是你快要睡著時，

and then all of a sudden you feel like you're falling or that you tripped and your body jolts itself awake. 片語搭配

突然覺得自己在下墜或絆了一跤，身體猛然抽動，把自己驚醒。

What's going on there is that as you fall asleep, 文法

這裡發生的情況是，當你逐漸入睡時，

your muscles relax and some part of your brain that's still awake notices that and feels like you're no longer supported. 文法

肌肉會放鬆，而大腦中某個仍醒著的部分注意到這點，並覺得你的身體失去了支撐。

You must be falling and it sends out a huge signal that causes all of your muscles to twitch, waking you up. 講解

它認定你一定正在下墜，於是發出強烈訊號，讓全身肌肉抽動，把你喚醒。

Oh, and déjà vu is not the only vu out there.

喔，對了，有「vu」的可不只有 déjà vu（既視感）。

There's also something known as presque vu or tip of the tongue. 慣用語

還有一種叫 presque vu，也就是「話到嘴邊」現象。

And this is what happens when you're familiar with something, 片語搭配

當你對某樣東西很熟悉時，就可能出現這種現象：

you know you know it, but for the life of you at that moment you cannot recall it. 慣用語

你知道自己明明知道，但那一刻無論如何就是想不起來。

It's like "What's that actor's name from that movie?

就像：「那部電影裡的那個演員叫什麼名字？

I've seen it 18 times.

我都看過 18 次了。

How can I not remember it? 語氣意圖

我怎麼會想不起來？

Wow."

天啊。」

One explanation of how that happens is that other words similar to the target word are being remembered

對這種現象的一種解釋是，大腦正在回想與目標詞相似的其他詞語，

and to help you out, your brain is actively blocking other stuff around it, including the word you're actually looking for. 片語動詞

為了幫你找到答案，大腦會主動阻擋周圍的其他資訊，其中也包括你真正要找的那個詞。

Now, this explanation is really nice because it might help explain why presque vu has a shared or social aspect.

這個解釋很不錯，因為它或許能說明為何 presque vu 會呈現出群體性或社交性。

Even a bunch of people in a group, all with separate brains,

即使一群人的大腦彼此獨立，

if they're given the same blocking words that are related,

如果給他們同樣一組會造成阻礙的相關詞語，

no one in the group can come up with the name until the subject is changed 片語動詞

那麼在話題改變之前，整組人可能誰都說不出那個名字；

and those words are no longer blocked and then all of a sudden someone goes,

等那些詞不再受到阻擋，突然就會有人說：

"Oh, Gary Sinise, that's who it was. 文法

「喔，是 Gary Sinise，原來是他。

Yeah, there you go." 語氣意圖

對，就是他。」

Okay, finally, jamais vu.

好，最後來談 jamais vu，也就是「陌生感」。

This is when something that you know,

這是指你知道的某樣東西，

something that you're familiar with, all of a sudden seems brand new and bizarre. 片語搭配

某個你很熟悉的東西，突然顯得全新又怪異。

Schizophrenic patients will sometimes see people they know and insist that it's not the person they know. 片語搭配

思覺失調症患者有時會看到自己認識的人，卻堅稱對方不是自己認識的那個人。

Instead, it's an imposter.

而是冒牌貨。

But all of us have probably experienced jamais vu to a certain extent. 片語搭配

不過，我們每個人或多或少可能都體驗過 jamais vu。

For instance, when you repeat a word over and over and over and over and over and over again, 片語搭配

比如，當你把一個詞一遍又一遍又一遍又一遍又一遍又一遍地重複時，

the word starts to lose its meaning and you start to think, 片語搭配

這個詞會開始失去意義，而你會開始想：

"What? How is this even a word? 語氣意圖

「什麼？這怎麼會是一個詞？

It's so weird."

太奇怪了。」

Well, scientists believe that happens because continuing to excite the neurons responsible for that word

科學家認為，這是因為持續刺激負責該詞的神經元，

causes them to become inhibited and further use is less intense.

會使它們受到抑制，之後再次使用時，反應強度就會減弱。

It's just crazy to think that there's so much out there in the world, in the universe, 語氣意圖

想想就覺得不可思議：在這個世界、這個宇宙中，還有那麼多事物

that we don't know, that we don't understand, that we haven't yet discovered. 表達脈絡

是我們不知道、不理解、尚未發現的。

But yet that very feeling of familiarity for what we do know can't always be trusted. 文法

可即便如此，我們對已知事物產生的那種熟悉感，也不一定可信。

About the only constant seems to be, 文法

似乎唯一不變的只有一件事——

as always, thanks for watching.

還是那句話，感謝收看。