Vision questionn?

Question

If having two eyes allows us to see 3 dimensionally, why do we close one eye when aiming a gun or a bow and arrow?

Answer 1

Two eyes help you with depth perception not dimension. Even if you only had one eye you would still have some depth perception.

Each eye takes in a picture of our surrounding and the brain puts both pictures together. When you are aiming two images in the brain would throw off the aim so we use our dominant eye for accuracy.

You should google this for a more scientific explanation.

Answer 2

BINOCULAR three dimensional vision is referred to as "stereo acuity".  True binocular stereo acuity only occurs when viewing objects quite close to the face.  Once you get out past 4 to 5 feet then monocular depth perception cues begin to take over in place of binocular depth perception.

That really doesn't completely answer your question though.  In a situation where you must SIGHT down a line or as in a rifle sight so that the front sight is placed in the notch of the back sight, keeping both eyes open would be more confusing to the brain because the eye not directly in line doing the sighting would be sending information to the brain at an off angle.

So to answer your question -- 1) binocular 3 dimensional vision is not used at these distances and 2) keeping both eyes open would be confusing to the brain.