When I only use one eye why is everything still three dimensional?

Question

When I only use one eye why is everything still three dimensional?

Answer 1

You have learned that the world is three dimensional and when you cover one eye you do not instantly forget all you have learned. Many clues such as shadows and perspective still exist. A distant telephone pole looks smaller and you interpret that as far away because all telephone poles are nearly the same actual height. But if you went to a theater showing a 3-D movie using for example red and green eye pieces, covering one eye would instantly destroy the illusion of depth where objects project from the screne toward you. But the ordinary clues such as telephone pole heights and shadows would still remain implying three dimensions.

Answer 2

We use binocular vision to measure depth of field (so you can tell how far away something is). When you close one eye, you will still be able to tell that an object has depth (it's not just 2D) because your brain interprets shadows and converging lines to create a 3D image. I remember a project in junior high art class in which I had to draw a street in perspective. To do this, I merely had to draw two converging lines with progressively shorter buildings on either side as the lines in the center came closer together. In that case, the picture looked 3D even though it was just a drawing on a page. (an example can be found at this site: http://www.sanford-artedventures.com/teach/lp_1pointperspect_complete.html)

Answer 3

I don't think that it is still three dimensional. The brain is incredible at adapting the information coming in through the one eye to still give some appearance of 3D. The true test is to cover one eye and have someone toss a ball to you. See how well you can catch it. This is my opinion, though.