Vision is the ability to see something and visual-spatial processing helps you make sense of what you see.
Vision is the ability to see what is there. Visual-spatial processing is the ability to see what is not there, too, in a sense. With good vision you can see what something looks like; with good visual-spatial processing you can imagine what something would look like if you turned it around or if you were standing somewhere else or if something else was covering part of it.
With good vision you can see objects; with good visual-spatial processing you can see how they might fit together.
With good vision you can see a bunch of lines and splotches of colors; with good visual-spatial processing you can see how those lines and splotches of color form meaningful patterns.
This is the ability that sculptors, painters, designers, engineers, and architects need. It comes in pretty handy for the rest of us too.
This post is an excerpt from:
Schneider, W. J. (2013). Principles of assessment of aptitude and achievement. In D. Saklofske, C. Reynolds, & V. Schwean (Eds.), Oxford handbook of psychological assessment of children and adolescents (pp. 286–330). New York: Oxford.