VISION SCIENCE AND PSYCHOLOGY APPROACH TO ADAPTATION PROCESSES LIED IN BASE OF VISUAL ILLUSIONS

Abstract

We have experimentally studied visual adaptation processes and compared results in various visual perception tasks. Adaptation stimuli were demonstrated on computer screen and differed each from other by their luminance, colour, duration and dynamics related to the excited retinal and consequently the cortex neural cells and corresponding visual areas. Depth and characteristic times of adaptation processes depend on visual perception task. The slowest characteristic times (in range up to 10 sec and more) from studied processes are for adaptation to size of moving targets exciting retinal cells by equiluminant and isochrome stimuli, that are processed along parvocellular and magnocellular visual pathways. We assume that neural cell physiology lays on the base of this kind of size adaptation. Another kind of size adaptation where retinal cell excitation is static realizes in Ebbinghaus illusion. Here parallel to ongoing adaptation process brain uses also previously acquired knowledge to make shift in decision about stimuli size, and physiological effects dominate over psychological effects in perception of such stimuli. Over- or underestimating sizes in Ebbinghaus illusion with non-moving stimuli realizes much faster, and the degree of perception errors practically does not depend whether margnocellular or parvocellular visual pathway are activated – contrary to adaptation to dynamic moving targets.