No, seriously. If you close your left eye, stare at this cross here with your right eye, and slowly move your head towards or away from the screen, the dot will disappear, revealing the exact location of your blind spot.

不，是真的。如果你閉上左眼，用右眼盯著這個十字然後慢慢地把頭靠近 (或遠離) 螢幕，黑點會消失，而那就是你的盲點。

The cells at the back of your eye transform light into signals that are sent to your brain.

眼睛背後的細胞把光線轉換成訊號，然後傳達到腦部。

But they are missing right here, because this is where nerves and blood vessels connect to the eye.

但是在這個地方剛好沒有這些細胞，因為這裡是神經跟血管跟眼睛連結的地方，

So anything at that point in your vision, you can't see, aka your blind spot.

所以在你視野當中，那個點裡的任何東西你都看不到，也就是盲點。

If we add a line through the image and you try again, you'll notice that your brain fills in information and makes you think the line is continuous instead of there being a hole in your vision.

如果我們在圖片中間加上一條線，然後你再試一次，你會發現大腦幫你加上了資訊，讓你覺得這條線是連續的，但是實際上你的視野有個缺口。

You also can't see all twelve of these black dots at once for a similar reason.

你無法同時看見這十二個黑點也是因為類似的原因。

Go ahead and try.

試試看啊。

Chances are you'll only see a fraction of them at once.

你應該一次只能看到一部份的黑點。

The exact point your eye looks at is focused, but your peripheral vision isn't great, and so your brain often makes assumptions for what's there.

你眼睛看的那個點是對焦的沒有錯，但是你周邊的視野並沒有那麼好，所以大腦會幫你猜旁邊是什麼東西。

Because of the consistent gray line pattern, your brain assumes the rest of the image is just like that and misses the black dots until you look directly at them.

因為你看到規律的灰線圖形，你的大腦直接斷定圖片剩下的部分都長一樣，所以你看不到黑點，除非你直接盯著黑點看。

These two rectangles are flashing at a phase with each other, right?

這兩個長方形輪流閃爍對嗎？

How about now?

現在呢？

For most, the rectangles will now seem to be flashing at the same time in phase, but they aren't at all.

大部分的人會覺得兩個長方形現在是同時閃爍的，但是根本不是這樣。

And yet, if we move these shapes beside them just a few pixels, you'll begin to see them out of phase again.

然而，如果我們把它們周圍的圖形移動一點點，你會看到它們開始不規則閃爍。

The surrounding area has a direct impact on how you see and perceive things, even if the result isn't correct.

周圍環境對你如何看以及感知東西有直接影響，即使結果是不正確的。

Not convinced?

不相信嗎？

Look at these flashing squares.

看著這兩個閃爍的正方形。

Except, what you may not have seen is that the middle square isn't flashing at all.

你可能沒有發現中間的正方形根本沒有在閃爍。

If we remove the outer square, we see it for what it is: a solid color.

如果我們把外面的正方形拿掉就可以看得很清楚：它是一個沒有在動的正方形。

Now, try reading the sentence inside it.

讀讀看這個句子。

Did you catch the extra word?

有發現多了一個字嗎？

Your brain doesn't always notice mistakes like these because it doesn't affect your comprehension of the sentence, and your brain will prefer to act quickly rather than to be perfectly accurate.

大腦並不會每次都抓出這種錯誤，因為它不會影響你理解這個句子，大腦會想要快速反應，而不是什麼東西都要完全精準。

Try staring at the middle dot in this illusion.

試試看盯著這個圖形中間的點。

When the picture isn't moving, the colors are clearly changing quickly, yet when the image starts rotating, the color change either seems nonexistent or much slower.

當這個圖形沒有在移動時，旁邊的顏色明顯地在快速改變，可是如果圖形開始旋轉，顏色的改變可能會消失或是變慢。

Our eyes and brain have evolved to see, but our vision makes assumptions based on learning, memory, and expectation.

經過演化後，我們的眼睛跟大腦學會怎麼看東西，但是我們的視野是根據學習、記憶以及預期接下來會發生的事件來做出判斷。

And all of these illusions take advantage of this adaptation.

以上看到的所有幻覺都是因為這個演化結果而產生的。

It's an advantage to have rapid information-processing, so instead of taking in every bit of detail to be 100% accurate, which would cause a brain-overload, your brain makes assumptions.

擁有快速資訊處理能力是個優勢，所以與其注意每個細節並且完全精準的感知外在環境，這會讓大腦資訊超載，你的大腦會自己下結論。

This faster perception allows for faster reflexes and faster conscious and unconscious decisions, an integral aspect of human nature.

這個較快速的感知方式讓你可以更快的反應，也可以更快做出有意識／下意識的決定而這是人性重要的一環，

Much like this halo. If you stare at the center spot for long enough, the brain will simply make it disappear.

就像這個圓環一樣，如果你盯著中間的點夠久，你的大腦會自動讓它消失。

It makes an assumption that the information is unchanging or unimportant, and as a result, you can't see it.

它覺得這個資訊沒有在改變或是一點都不重要，所以你才看不到它。

Love tricking your brain with illusions?

你也喜歡用這些幻覺來騙騙自己嗎？

We've put together a playlist of our favorite ones that you can watch by clicking the screen.

點一下螢幕就可以看到我們幫你挑選的幻覺影片喔！

Don't forget to subscribe for more weekly fun science videos.

別忘記訂閱我們的頻道就可以每個禮拜看到更多有趣的科學影片。