(单词翻译:单击)
Hopefully, you have never had a near-death experience.
希望你从未有过濒死体验。
But if you have, I'm glad that you survived it.
但如果你有过，很高兴你活下来了。
Uh, also, maybe this sounds familiar: A blinding white light.
也许这情景听起来很熟悉：一道眩目的白光。
Your life flashing before your eyes.
你的生命体在你眼前闪现。
Floating out of your body and looking down on that body from above.
灵魂漂浮在你的身体外面，俯视着它。
Honestly, it might sound familiar either way.
老实说，这可能听起来很熟悉。
At this point, the near-death experience is a bit of a cliche in pop culture, but this stuff really happens.
在这一点上，濒死体验在流行文化中显得有点儿老套，但它确实会发生。
Near-death experiences are most likely caused by a bunch of different processes,
濒死体验很可能是由一堆不同的流程引起的，
and scientists are still figuring out all of the mechanisms.
科学家们还在研究它所有的机制。
But either way, these experiences probably aren't as mystical as they seem.
但不管怎样，这些经历可能不像它们看起来那样神秘。
There are accounts of near-death experiences going back to ancient Greece,
濒死体验的记载可以追溯到古希腊，
and because modern medicine can bring people back from the brink of death more often,
因为现代医学可以让人们更频繁地从死亡边缘恢复过来，
they're even more common now.
所以这种经历现在更普遍了。
What's weird is that most people who have them report seeing the same kind of stuff.
奇怪的是，大多数有这种经历的人都报告说他们看到了相同情景。
The white light. The out-of-body experience. The sense of peace. An awareness of being dead.
白光。灵魂出窍体验。平和的感觉。一种死亡的意识。
The experiences are so universal that there's actually a standardized questionnaire
这些经历如此普遍，以至于有一个标准化问卷
to evaluate whether or not someone has had a near-death experience.
来评估某人是否有濒死体验。
But when it comes to understanding why they happen, things are less clear.
但涉及到理解它们发生的原因时，事情就不太清楚了。
For one, there's virtually nothing medically, demographically, or psychologically different about the so-called "experiencers"
首先，所谓的“体验者”在医学、人口统计学或心理上
compared to non-experiencers who have also almost died.
与将死的非经验者相比没什么不同。
They're also just really hard to study.
其次，它们很难研究。
It's generally frowned upon to almost kill someone while they're in an fMRI machine.
人们待在功能磁共振成像机里几乎会杀死他们，这通常是不被允许的。
Also, studies of near-death experiences have major sampling issues.
此外，对濒死体验的研究也有重要的抽样问题。
Studies done after the fact rely on experiencers identifying themselves as participants,
事后所做的研究依赖于体验者将自己视为参与者，
which can cause some serious bias.
这可能会造成严重的偏见。
But other studies, like ones where experimenters waited on call for people to go into cardiac arrest,
但是其他的研究，比如实验者等待要求进入心脏骤停状态的研究
have a hard time getting enough participants for a good sample size.
很难找到足够多的参与者，取得适当的样本量。
Also, waiting around for people to start dying? Not a super-fun job.
那么等待人们开始死亡吗？这个工作没意思。
But even though they're hard to study, there are tons of ideas about what could cause these experiences,
但即使它们很难研究，还是有很多观点说明这些体验的成因，
and they're probably not just caused by one thing.
而且原因可能不是一种。
One idea is that rather than experiencers seeing and feeling the same things
一种观点是，体验者没有看到和感受到同种情景，
because they're actually having similar experiences, they see and feel them because they expect to.
他们因为确实有相似经历，期待能看到并感受到它们，所以才会如此。
This kind of thing happens all the time, like in eyewitness testimonies.
这种事经常发生，比如目击者的证词。
People are pretty suggestible, so it's reasonable to think that
人们很容易受影响，所以有理由认为
the cliches about near-death experiences might impact what people actually see and feel during them.
关于濒死体验的陈词滥调可能会影响人们体验期间真正看到和感受到的东西。
Another view is that they are a psychological response to the threat of death.
另一种观点认为，濒死体验是人们对死亡威胁的心理反应。
Beginning in the 1930s, psychologists suggested that these experiences were a result of depersonalization,
在20世纪30年代初，心理学家认为这些经历是人格解体的结果，
where you feel detached from your identity and what's happening to you.
你感到自己与你的身份和你身上经历的事分离了。
Basically, you know you're dying, but you feel completely detached from it. It's like it's not real.
它基本上是，你知道你正在死去，但你觉得自己完全从身体脱离了。这好像不是真的。
Among other things, that would also explain why near-death experiences cause calmness and peacefulness.
除此之外，这也可以解释为什么濒死体验会带来平静。
More recent research has argued that dissociation,
最近的研究认为，
where your consciousness seems independent from your real, physical experience, is actually to blame.
你的意识似乎与你真实的身体体验脱离，这种解离症才是罪魁祸首。
Daydreaming is a totally normal example of this, but an extreme case is an out-of-body experience.
白日做梦是这一症状的正常例子，但也有灵魂出窍的极端例子。
And there's some evidence to back this one up.
有一些证据支持这个观点。
All kinds of trauma often result in dissociation, so there are tests to clinically identify it.
各种各样的创伤常常导致解离症的发生，因此有临床试验来识别它。
The tests ask responders to identify how often they do things like totally zone out while watching TV
这些测试要求反应者确定他们做这些事的频率，比如看电视时开小差，
or have no recollection of an important event.
或者不记得某件重要的事情。
A study from 2000 looked at 134 subjects who had come close to death,
2000年的一项研究调查了134名曾接近死亡的受试者，
96 of whom had had near-death experiences.
其中96人有濒死体验。
They found that the experiencers scored much higher on the dissociation test,
研究人员发现这些体验者在解离症测试中得分更高，
meaning they were more prone to mentally check out of situations.
也就是说，他们更倾向于精神不在状态。
It's also possible that near-death experiences could be entirely or partly biological,
濒死体验也有可能完全或部分是由生理因素导致的，
and there are a number of possible mechanisms that could explain the things experiencers see and feel.
有很多可能生理机制可以解释体验者看到和感受到的东西。
For instance, the combination of fear and depriving the optic nerve of oxygen has been known to cause tunnel vision.
例如，众所周知，恐惧与视神经缺氧一起会导致隧道视觉。
And, when faced with the extreme stress of dying,
而且当人们面对死亡的极端压力时，
the brain probably releases all kinds of chemicals to protect itself, which can lead to those other weird symptoms.
大脑可能会释放各种各样的化学物质来保护自己，这可能会产生其他奇怪的症状。
A 2004 study showed that out-of-body experiences can be triggered by stimulating the temporoparietal junction,
2004年的一项研究表明，离体体验可以通过刺激颞顶交界处触发，
a part of the brain that plays a role in processing information from your environment
颞顶交界处是大脑的一部分，它在处理环境信息
and in distinguishing between yourself and others.
以及区分自己和他人中发挥作用。
Experiments with an anesthesia called ketamine have also suggested that,
用一种叫做氯胺酮的麻醉剂做得实验也表明，
under stress, the brain might release neurotransmitters that cause detached, dreamlike states or hallucinations.
在压力下，大脑可能会释放神经递质，导致分离、梦幻状态或幻觉的产生。
And other studies have shown that stimulating a part of the midbrain called the locus ceruleus can release noradrenaline,
其他的研究已经表明，刺激中脑一个叫蓝斑核的部位可以释放去甲肾上腺素，
which is involved in fear and stress reactions and can alter your emotions and memories.
后者参与恐惧和压力反应，可以改变你的情绪和记忆。
Both of those processes could be related to peaceful emotions, hallucinations,
这两个反应都与平和的情绪、幻觉
and that sense of your life flashing before your eyes.
以及生命体在你眼前闪现的感觉有关。
So it's possible that near-death experiences are caused by a combination of all of these factors, biological and otherwise.
所以濒死体验可能是由所有这些因素——生理因素和其他因素共同造成的。
Of course, there are critics of these studies, and they make a good case.
当然，这些研究也有批评者，他们举了一个不错的例子。
They argue that, if these are normal biological mechanisms associated with the stress and trauma of death,
他们认为，如果这些是与压力和死亡创伤相关的正常生理机制的话，
why doesn't everyone who almost dies have them? We don't know.
为什么不是每个濒死之人都有呢？我们不知道。
But for people who do have them, there are a whole bunch of scientific explanations for where they might come from.
但是对于有这些的人来说，有很多科学解释可以说明它们的来处。
And whether they're caused by biology, psychology, or something in between,
不管它们是由生物学引起的，还是心理学引起的，还是两者共同引起的，
near-death experiences can teach us a lot about how our brains work and that weird thing that we call "consciousness".
濒死体验都可以告诉我们很多关于大脑的工作方式，以及我们称之为“意识”的奇怪事物方面的内容。
Thanks for watching this episode of SciShow Psych, brought to you by our patrons on Patreon.
感谢您收看本期的心理科学秀，它是由Patreon赞助播出的。
If you'd like to help support the show and help us keep making episodes like this one,
如果你想支持本节目，并帮助我们继续制作这类节目，
you can go to patreon.com/scishow.
可以登录patreon.com/scishow。
We very much appreciate everybody who does that.
我们非常感谢每一个这样做的人。
