Cartoon-style line drawings contain very condensed information, after all most of the page stays blank. Yet, they constrain the contents of immediate visual awareness to an extraordinary extent. This is true even for drawings that are--though nominally "representational"--not even in central projection. Moreover, the strokes used in a drawing may…

Human visual perception is a fundamentally relational process: Lightness perception depends on luminance ratios, and depth perception depends on occlusion (difference of depth) cues. Neurons in low-level visual cortex are sensitive to the difference (but not the value itself) of signals, and these differences have to be used to reconstruct the…