Monday, August 27, 2012

summation or conclusion?

So, I'm realizing now that this note from a few days ago is touching on this entry from several months back (if only I could keep everything in my head at once...). In the latter, I was talking about the idea that visual experience is a stack of phenomena, extending all the way down to the optical image, even to the light field, and all the way up to cognition and emotion. In the former, I realized that my standing, computational interpretation of the classification image experiment involves an assumption that estimates of a particular psychological construct - perceived contrast - are mediated by the same processes whether the stimulus is simple or complex.

This stance doesn't conflict with the 'stack' idea, but when you think of both together it seems dubious. With simple stimuli, there isn't much else elicited by the visual pattern, so estimates of its properties can be localized to a small set of possible mechanisms, which is the point of using simple stimuli in the first place. So, there are multiple layers to the stack, but most of them are relatively empty or inactive. When the stimulus is complex, all those other stacks are now active, and filled with activity which is ostensibly more important and interesting to the observer. Is it reasonable to continue to assume that the observer can make use of the same information in that 'spatial vision' layer that he could when there was nothing to distract him elsewhere?

I realized this connection because I was thinking of the implications of one alternative (complex visual qualia are the result of highly nonlinear summation of simple visual qualia) or the other (complex qualia may be inferences drawn from 'basis' qualia, that could possibly exist - as perhaps in a dream - independently of those bases). How do you tell the difference? Take away the spatial vision level, and see what is left. How to do this? Lesions maybe, but the first thing that comes to mind is to compare what imagery looks like when you're seeing it versus when you're dreaming it.

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