Refer to the section of the interview beginning with Terry Gross saying, quot;You say something in your book that I suppose is obvious but it wasn't...

Refer to the section of the interview beginning with Terry Gross saying, "You say something in your book that I suppose is obvious but it wasn't obvious to me. You write: seeing isn't passive." Specifically, Dr. Barry clarifies that "when you look at a close object, you have to turn in your two eyes so that the image that you're looking at falls on the central part of the retina, called the fovea, of the two eyes. When you look at a more distant object, your eyes will turn out."

Which concept from vision does this discussion best relate to?

Binocular disparity

Convergence

Occlusion

Object constancy