If depth perception works because the brain checks the difference in the position of the object between the two eyes and concludes how far away it is, how can we still see depth when one eye is closed?

Question

If depth perception works because the brain checks the difference in the position of the object between the two eyes and concludes how far away it is, how can we still see depth when one eye is closed?

In: 3602

Answer 1

Because that isn’t the only piece of information your brain uses. It basically collates a bunch of different pieces of information:

1. Your eye is always moving slightly and when your eye looks in different directions, it sees different things based upon the relative position of objects in your 3D environment.
2. Over the course of your life you have lots of experience with seeing various objects and your brain develops an expectation of their size. So something that your brain believes should be large but looks small will be interpreted as being further away, and something that your brain believes should be small but looks large will be interpreted as being closer.
3. The parallax created with two eyes can be replicated simply by moving. How things change relative to other objects as you move laterally, and how their size appears to change as you move back and forth, gives your brain information with which to construct a perception of depth.