Parallel Processing in Human Vision: History, Review, and Critique

Abstract

Publisher Summary This chapter discusses parallel processing in human vision. It illustrates that, it was the discovery of X and Y cells in cat in the 1960s that stimulated an acceleration of psychophysical investigations specifically focused on defining the properties of analogous pathways in humans. The revisions of the sustained-transient channel approach has been accompanied by a shift from drawing analogies with the X and Y pathways of cat to more recent analogies with the opponent-color P and broad-band M pathways in monkey. The latter development has broadened the psychophysically defined distinctions between parallel pathways in human vision by including, along with temporal and spatial response differences, differences of chromatic sensitivity. These distinctions in turn have been criticized on theoretical and methodological grounds and are in need of revision. In addition, they also are closely related to recent distinctions made between pathways for object recognition and spatial vision and similarly for visual function in near (peripersonal) and far (extrapersonal) space. Moreover, extensions of the parallel-channels approach help inform about a number of other phenomena such as selective spatial attention and reading, and they provide a means of investigating a number of visual abnormalities associated with specific reading disability, ophthalmological disorders, and, possibly, also schizophrenia.