Shows that the perceived shade of gray depends on the luminance relationship between surfaces perceived to be in the same plane and not between surfaces that are merely adjacent in the retinal image. This implies that lateral inhibition cannot explain lightness constancy. (MLH)

Discusses techniques for studying large-scale brain activity, insights from computational modeling, and cognitive processes that could lead to a better understanding of cognition. Describes interactions between psychology and physiology in perception, structural levels of organization in the nervous system, techniques and research strategies. (RT)