Depth must be hidden. Where? On the surface.

Have you ever seen people close an eye and hold their hands out in front of their face to make a frame when they contemplate a photograph? It's a gesture that, even if it promised to transform me into the photographic love child of Edwards Weston and Steichen, I can never bring myself to do. It feels silly and it's embarrassing to admit that I don't have some secret photographer mind-trick that accomplishes the same thing. But I do sometimes close one eye when looking at a scene to photograph. The reason is that, by closing an eye, you can turn off your stereo vision. I never really gave it much though. It just seemed obvious since photography, at a fundamental level, is about reducing the three dimensional world to two dimensions. And it really does help avoid unfortunate mistakes that occur when you don't see how your subject will merge with the background—the age old light-pole-sticking-out-of-the-subject's-heads problem.

It turns out that a significant number of people, around ten percent of the population, are stereo blind—they lack the ability to gather depth information using the binocular disparity between the eyes. They don't need to close one eye. One major cause of stereo blindness is misalignment of the eyes and misaligned eyes can be diagnosed through photographs. Dr. Margaret S. Livingstone, Professor of Neurobiology at Harvard Medical School, studied photographs of baseball players and found unsurprisingly that, with the notable exception Babe Ruth, famous baseball players tend to have very well aligned eyes, suggesting that excellent depth perception is an asset in baseball. Not really surprising. I bet she'd find similar results for tennis players, rodeo clowns, and trapeze artists.

She also looked at photographs of famous artists found the opposite, which is a little surprising. Portraits of famous artists she examined showed a unusual percentage with poorly aligned eyes which would indicate stereo blindness. The list includes Marc Chagall, Edward Hopper, Gustav Klimt, Jasper Johns, Frank Stella, Man Ray, Chuck Close, Thomas Moran, Willem de Kooning, Roy Lichtenstein, Alexander Calder, Robert Rauschenberg, N. C. Wyeth and Andrew Wyeth. This suggests that stereo vision might be a hindrance to producing art, that perhaps if you already see the world in two dimensions, it's easier to produce two dimensional art. The stereo blind artist avoids the distraction of depth cues that can't be painted and may be more aware of those that can. Without the benefit of stereo vision you are probably more aware of things like linear & aerial perspective, dimensional hints from shadow, relative sizing, occlusion, etc. because you would depend on them more than other people in order to navigate the world. While most of us need to learn to see these cues in order to produce art, the stereo blind need to intimately understand them to get up a flight of stairs or drive a car. That's probably a gross simplification as watching Dr. Livingstone's fascinating presentation on visual perception, What Art Can Tell Us About the Brain, will make clear. If sitting through an hour-long lecture is not your thing, this short paper from the Harvard Medical Alumni Bulletin has a good overview of her work on this subject as well as a suggestion that these findings correspond to studies linking dyslexia and creativity together with problems involving depth perception. A surprising number of famous artists are dyslexic as well as stereo blind.