Are Images Flat?
Okay, here’s another post about the spatial properties (or not) of visual images. I seem to be on a kick!
Pete Mandik reminded me of this issue when he said something in his comments on my last post that seemed (perhaps only seemed?) to imply that he regarded images as generally two-dimensional.
We certainly talk, sometimes, as though they are. Most tellingly, I think, we call images “pictures” (in the mind’s eye), not (say) “sculptures”. Stephen Kosslyn, in his seminal 1980 book on imagery, describes the imagery space as “roughly circular” and compares its horizontal and vertical dimensions. He does not (that I recall) discuss its depth. Likewise, he says that position in the imagery matrix can be indicated by a pair of co-ordinates (polar co-ordinates r and theta) – not, as would be necessary for a three-dimensional imagery space, a triplet of co-ordinates (such as the Cartesian x,y,z or the polar r, theta, and phi). His sample portrayals of images never indicate depth.
In my posts here and here and my article on the question of whether things look flat, I suggest that our tendency to think of circular objects viewed obliquely as “looking elliptical” and distant objects as “looking small” derives primarily from an over-analogizing of visual experience to flat media such as paintings and pictures. I won’t rehearse those arguments again; but if that’s right, then perhaps our (at least some of our) tendency to think of images as flat derives from a similar over-analogizing and should be treated with similar skepticism.
One can accept that images are often (or even typically?) three-dimensional without going so far as to say that we can imagine something from multiple perspectives at once -- just as we can say that our visual representations and visual experience are fundamentally and ineliminably marked out in three-dimensional space (even monocularly) without saying that we can see from more than one angle at once.
So I’m wary of our too easily supposing that our imagery appears as if on a flat plane. But maybe, nonetheless, it does. I wonder about readers' introspective sense of this; and I’d be interested to hear also if you have reflections on neuroscientific or behavioral tests that might shine light on the question.