It is argued that a reflectance channel that requires priority information is shown to be less plausible for the human visual system than J. L. Dannemiller (1989) argued. In the response, Dannemiller replies that lightness is not an illuminant invariant surface descriptor when daylight illuminant substitutions are considered. (SLD)

F. Attneave (1954) famously suggested that information along visual contours is concentrated in regions of high magnitude of curvature, rather than being distributed uniformly along the contour. Here the authors give a formal derivation of this claim, yielding an exact expression for information, in C. Shannon's (1948) sense, as a function of…

Neuropsychological findings relevant to the question of whether visual imagery is visual or perceptual are reviewed and compared to cognitive psychology theories. Imagery does not appear to represent information acquired through visual sensory channels; rather, it seems to use some of the same neural representational machinery as does vision. (SLD)

A large body of data is reviewed to support a new theory of motion perception described by S. Grossberg and M. E. Rudd (1989). The Motion Boundary Contour System is used to explain classical and recent data about motion perception that have not been explained by other models. (SLD)