Time courses in visual-information processing: some theoretical considerations.

Abstract

In the literature two different views with regard to the time course of activation of "recognition units"--hypothetical entities that represent identity information--are proposed. Both views are derived from a restricted set of phenomena in visual perception. The first view gets its intuitions from phenomena such as those summarized by Bloch's law; these phenomena show integration or summation of activation over time. This "grow-and-grow" view assumes that recognition units accumulate activation gradually over time. The second view finds its inspiration in phenomena such as Mach-bands and simultaneous contrast; these phenomena show inhibition or steady-state suppression over time. This "grow-and-shrink" view assumes that the activation levels increase fast initially and then start to decrease. The perception literature strongly suggests that it may be light intensity that determines whether mainly integration (and phenomena such as Bloch's law) or inhibition (and phenomena such as Mach-bands) is obtained. So it is also likely that both information-processing views apply only to a limited range of intensity conditions; the "grow-and-grow" view to conditions of low-light intensities, and the "grow-and-shrink" view to conditions of intermediate- and high-light intensities. It is argued that, to arrive at a complete view, a visual phenomenon that applies to the complete range of light intensities should be taken as a background for generating hypotheses about time courses in visual-information processing. The Broca-Sulzer effect is such a phenomenon. Starting from this phenomenon a simple, synthesizing, information-processing model is derived that is compatible with both the "grow-and-grow" view and the "grow-and-shrink" view.(ABSTRACT TRUNCATED AT 250 WORDS)