未登录,请登录后再发表信息
最新评论 (0)
播放视频

现在究竟是什么?

What Exactly is the Present?

At the 1939 world’s fair in New York,
在1939年的纽约世博会上
the exciting new tech was the live television broadcast.
电视机是项振奋人心的新技术
Roosevelt became the first president to address the nation live on TV
罗斯福成为了第一位通过电视向全国发表演讲的总统
But for years leading up to this event,
但这之前的几年里
engineers have been working on one particular technical problem:
工程师们一直在研究一个特殊的技术问题
How to ensure the audio and video remain perfectly synced during the live broadcast ?
如何在播放时确保音画同步?
Without this, words and lip movements wouldn’t match up,
不这样的话 字幕对不上口型
which would be annoying and distracting for viewers.
便会极其影响观感
So, how did they do it ?
所以 他们怎么做到的呢?
Well actually, they didn’t,
实际上他们并未做到
instead they discovered something pretty incredible:
但他们发现了一些不可思议的东西:
We are not very good at discerning whether audio and video are in sync
我们不擅于辨别音画是否同步
For example, I intentionally delayed the audio of this entire monolog
例如 我故意把整个独白的音频延迟了
nearly a 1/10th of a second and did you notice?
将近十分之一秒 你注意到了吗?
I’ll clap to make it more obvious.
我拍下手 让它更明显
The engineers also found that there’s an asymmetry
工程师们还发现我们对这种
in our tolerance for this misalignment,
偏差的容忍度存在不对称性
we don’t really notice if a sound lags video by up to 125 milliseconds
一个视频的声音延迟125毫秒 我们不会察觉
but we can tell something is wrong if it’s leading the video by more than 45 milliseconds.
但如果它先于视频超过45毫秒 我们就会察觉问题
And to understand why, take a look at this:
要理解原因 请往下看:
Here I am bouncing a basketball as I walk away from the camera.
我一边拍打篮球 一边远离镜头
The sight and the sound of the bounces match up perfectly;
篮球弹跳的音画完全同步
but as I walk away, you know the sound will be increasingly delayed
但当我离开时 声音会一点点延迟
due to the extra time it takes the sound to reach the camera,
因为声音到达相机需要额外的时间
but the sounds still appears synced.
但音画仍是同步的
This is because your brain is not reporting to you each instance exactly as it happens,
因为你的大脑并未准确地向你报告发生的每个事件
but rather a short interval of time reorganised to make sense,
而是将短暂的时间段落重组
so in this case your brain automatically aligns the sound with the sight of the bounce.
在这种情况下 你的大脑会自动将拍球的音画同步
At least, up to a point.
至少在某种程度上如此
Once I’m over 30 meters away,
一旦我超过30米远
the sound is now delayed by over 100 milliseconds
此时声音的延迟超过100毫秒
and your brain no longer integrates the information from your eyes and ears.
你的大脑将不再整合来自眼睛和耳朵的信息
Here, let me play the actual sound of the bounce
下面 我会同时播放拍球的声音
together with the sound as received by the camera.
和摄像机接收到的声音
This explains why sound can lag video by more than it can lead.
这就解释了声音为何会延后于视频 而不是先于视频
I mean imagine you were at a basketball game,
想象你在看一场篮球比赛
and because of how far away you’re sitting, the sound is delayed.
因为你坐得太远 所以声音被延迟了
Your brain can handle that.
你的大脑会处理好的
but if the sound precedes the sight of an event
但如果声音先于事件的画面
that would look really odd
那就会看起来很怪
because that’s something that would never happen in nature.
因为这在自然界中是不可能发生的
This is why the broadcast guidelines for acceptable audio and video mismatches
这便是为何 声音滞后于视频
are skewed in favour of audio lagging behind the video,
这种音画失调是能够被接受的
our brains are good at aligning audio with the vision that preceded it.
我们的大脑擅长将声音与之前的画面联系起来
We can actually exploit our audio-syncing-capabilities
我们其实能利用我们的音画同步能力
to produce some strange results
来产生一些奇妙的结果
for example, we created this computer program
例如我们开发了这样一款程序
where when you press the space bar a light appears on the screen.
当你按下空格键时 屏幕上就会出现一个指示灯
But not immediately,
但并非立刻
there is an 80ms delay between the button push and the light coming on.
按下按钮和灯亮之间有80毫秒的延迟
In a study participants who familiarised themselves with a similar program
在一项研究中 参与者熟悉了类似的程序后
came to believe that the light turned on immediately after they pushed the button,
认为在他们按下按钮后灯会立刻亮起来
just as our brains sychronized the sight and sound of the basketball bounce
就和我们的大脑可以同时看到和听到篮球弹跳一样
Press the space key once to begin
一按空格键就是开始
This is just the section where you get the idea of what it does, so you push the spacebar
了解它的运作后 你按下空格键
Now watch what happens when you remove the delay.
现在观察当你去除延迟后会发生什么
That last one came up without me even pressing anything!
我没按最后一个就出来了!
You didn’t press anything and it just flashed up there?
你什么都没按 就突然闪了出来?
Right!
是的!
Some participants were convinced that the light came on before they pushed the button.
一些参与者确信 在他们按下按钮之前灯已经亮了
They believed that something else caused the light to come on,
他们认为是别的东西导致屏幕亮了起来
even though it was their action that made it happen.
尽管这一切都是他们的行为造成的
This is remarkable beause causality the idea that
值得注意的是 因果关系
one thing leads to another is fundamental through our understandng of the world
是我们对世界认知理解的基础
otherwise how would we know who shot first.
否则我们怎么知道是谁先开的枪
Babies as young as eight months can demonstrate an understanding of causality
八个月大的婴儿就可以辨别因果关系
when watching a caregiver wind a music box if the music stops
看着大人在音乐停止时给八音盒上弦
the babies touch the caregiver’s hand to get the music to start again.
婴儿触摸大人的手让音乐重新开始
Causality is something we re hardwired to recognize
我们天生就能识别因果关系
but even this core part of our brains can be fooled.
但我们大脑的核心部分也可能被蒙蔽
The flash lag effect gives further insight into how this happens
闪滞效应进一步揭示了这是如何发生的
Stare at the red square in the middle of the screen
盯着屏幕中央的红块
and remember what you see when the flash happens.
并记住闪光时你看到了什么
where was the ring when the flash occurred ?
闪光出现时环形在哪里?
If you’re like most people you probably saw the flash in the top half of the ring.
大多数人可能看到闪光在环形上半部分
but what actually happened was the flash appeared in the exact center of the Ring.
但实际上闪光正好出现在环形的中心
So our perception of the flash seems to be delayed.
所以我们对闪光的感知似乎延迟了
To explain this result scientists hypothesized that the brain was anticipating motion.
为了解释这一结果 科学家们假设大脑正在预测运动
You see the flash behind the ring
你看到环形后面的闪光
because your brain is predictig where the ring will be
是因为你的大脑预测了环形的位置
not where it actually is when the flash happens to.
而非闪光发生时的实际位置
To test this hypothesis,
为了验证这个假设
neuroscientist David Eagleman and his team
神经科学家大卫·伊格曼和他的团队
modified the experiment so that the ring reverses direction right at the moment of the flash.
修改了实验 使环形在闪光的那一刻转向
Now what did you see?
现在你发现了什么?
If the brain was predicting the motion of the Ring ,
如果大脑能够预测圆环的运动
you should see exactly the same thing as before
你应该看到和之前相同的现象
with the flash on the top side of the Ring
闪光在圆环正上方
But most people see it in the bottom half of the ring .
但大多数人看到闪光在环形的下半部分
How is this possible considering
怎么会这样 考虑到
all the frames leading up to the flash were exactly the same in both cases?
导致闪光的每一帧都是完全相同的
If our brains were anticipating motion
如果我们的大脑在预测运动
then we would have had to somehow known in advance
那么我们本应提前知道
that the ring was going to reverse direction.
环会反向运动
and that seems impossible.
那看起来不太可能
So the alternative hypothesis is that where we see the flash occur
另一种假设是我们看到闪光发生的地方
depends on what happens after the flash.
取决于闪光之后发生了什么
There is a delay between the flash occurring and you perceiving it.
在闪光发生和你感知它之间有一个延迟
The stuff that happens during that delay is actually incorporated into your perception of the event.
在延迟期间发生的事情实际上纳入了你的事件知觉
This is incredibly cunterintuitive and it calls into question our perceptions of causality .
这及其有悖常理 使我们质疑对因果关系的感知
The underlying cause of all of these illusions is the same.
这些错觉的潜在原因都是一样的
What we perceive as the present is not just one moment
我们所感知的现在不是一个瞬间
but a short interval of time which is a round of tenth of a second long .
而是一个很短的间隔 大约十分之一秒
And during this period your brain can perform manipulations that distort your perception of time.
在这期间大脑可以操纵并歪曲你对时间的感知
And rearrange causality.
并重新排列的因果关系
This interval has been called the specious present
这段时间被称为貌似真实的现在
A term coined by E Robert Kelly.
由E·罗伯特·凯里首次使用
All the way back in 1882,
回溯到1882
he said: All the notes of a bar of a song seemed to the listener to be contained in the present
他说 在听众看来 一首歌一小节的所有音符都包含在当下
All the changes of place of a meteor seemed to the beholder to be contained in the present .
所有的变化 在旁观者看来都发生在当下
The present is really a part of the past a recent past.
现在其实是过去的一部分即最近的过去
delusively given as being a time that intervenes between the past and the future.
被错误地认为是介于过去和未来之间的时间
Let it be named the specious present.
那就命名为 貌似真实的现在吧
Why do we experience time in this ilusory way?
为什么我们会以这种虚幻的方式感受时间?
We feel like we’re living in each instant
我们感觉我们生活在每一个瞬间
but what we are actually experiencing is a short period of time.
但我们实际经历的只是很短的一段时间
I think it’s not so that our brains can sync up the sight and sound of distant events
我认为我们大脑之所以音画同步
so we can watch TV and movies without distractions
不是为了能够不受干扰地看电视和电影
but because fundamentally our brains need to hold
而是因为 我们的大脑根本上需要同时
multiple moments at once to make e sense of the world
记忆多个时刻 才能理解这个世界
Just as you can’t read a book letter by letter
就好比你不能逐个字母地读一本书
you can’t make sense of the world and form memories instant by instant.
你也不能逐个时刻地理解这个世界 形成记忆
So we live in the specious present
我们生活在似是而非的现在
under the illusion that we experience each moment exactly as it happens
错以为 我们在体验每一刻的发生
Hey! A lot of the research in this episode was performed
本集的很多研究都是由
by neuroscientist David Eagleman
神经科学家大卫·伊格曼进行的
and he’s actually written a book entitled The Brain: the Story of You
他还写了一本书叫《大脑:你的故事》
which includes a lot of details of his research
包括他研究的很多细节
so if you want to know more about these topics
如果你想了解更多相关话题
I highly recommend you check out his book
我强烈推荐你看看他的书
and in fact you can download it for free
你可以免费下载
by going to audible.com/veritasium
登录audible.com/veritasium
where this book is written by David Eagleman himself
这本书是大卫·伊格曼本人写的
But if you’re not interested in this one
但如果你对这本书不感兴趣
you can also pick any other book of your choosing for a one-month free trial.
你也可以选择其他任何一本书 免费试用一个月
Audible is a great audiobook website
Audible是一个很棒的有声书网站
with hundreds of thousands of titles in all areas of literature
有成百上千本文学领域书籍
including fiction nonfiction and periodicals
包括各种小说 散文和期刊
Plus Audible is a Longtime supporter of veritasium
况且Audible是Veritasium栏目的长期支持者
so I really want to thank them for helping me to keep doing
所以我真的很感谢他们
what I’m doing and making these videos.
能帮助我 让我做这些视频
And I want to thank you for watching.
感谢你的收看

发表评论

译制信息
视频概述

什么是似是而非的现在呢? 我们的大脑又是如何来感知时间的? 一起来一探究竟!

听录译者

收集自网络

翻译译者

eudemonia

审核员

审核员GURU

视频来源

https://www.youtube.com/watch?v=K4vyRvMASPU

相关推荐