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Saturday, May 9, 2009

Top-down Processing in Visual Perception Part IV: Ramifications

This is the final instalment of my series on top-down processing in the visual system (links to part I introducing the topic, part II discussing faces and anthropomorphizing, and part III discussing artificial edges). While I find the topics of vision and optical illusions to be fascinating in their own right, I think the analysis of perception and cognition is also vitally important. This is by no means an original outlook, as David Hume made the statement in the introduction to his A Treatise of Human Nature:
'Tis evident, that all the sciences have a relation, greater or less, to human nature; and that however wide any of them may seem to run from it, they still return back by one passage or another. Even Mathematics, Natural Philosophy, and Natural Religion, are in some measure dependent on the science of Man; since they lie under the cognizance of men, and are judged by their powers and faculties.
While couched in somewhat archaic English, Hume's statement strikes me as remarkably astute. In many ways, our brains function as vast pattern-matchers. Understanding the underlying cognitive tricks we use to analyse perception is an important endeavour for making sense of our own observations, and avoiding mistakes in our interpretation of experimental results. Of course, the most pertinent application of perceptual understanding is in automated sensory processing applications (like machine vision which I have discussed before), but as Hume pointed out, it also matters in the way our thought processes interact with every other endeavour. We must be wary of our tendency to anthropomorphize, or to view causal connections that are not actually there. Realising our tendency to perform processing without being consciously aware of it helps reinforce the necessity of mathematical, logical, and statistical tools on which to rest one's theories.