400
It is tempting to think that your eyes are simply mirrors that reflect whatever is in front of them. Researchers, however, have shown that your brain is constantly working to create the impression of a continuous, uninterrupted world.
For instance, in the last 10 minutes, you have blinked your eyes around 200 times. You have probably not been aware of any of these interruptions in your visual world. Something you probably have not seen in a long time without the aid of a mirror is your nose. It is always right there, down in the bottom corner of your vision, but your brain filters it out so that you are not aware of your nose unless you purposefully look at it.
Nor are you aware of the artery that runs right down the middle of your retina. It creates a large blind spot in your visual field, but you never notice the hole it leaves. To see this blind spot, try the following: Cover your left eye with your hand. With your right eye, look at the O on the left. As you move your head closer to the O, the X will disappear as it enters the blind spot caused by your optical nerve.
O X
What is to explain how visual perception works?