Effects of Movements upon the Appearance and Duration of a Prolonged Visual Afterimage: 2. Changes Arising from Movement of the Observer in Relation to the Previously Afterimaged Scene

Abstract

Gregory et al. (1959) reported that visual afterimages undergo changes in appearance when the observer moves. Davies in part 1 of this series reported qualitative and quantitative effects upon the appearance and duration of afterimages when a portion of the body incorporated in the afterimaged scene was moved. This paper reports an experiment in which 12 subjects afterimaged a long narrow corridor before (a) standing still and observing the afterimage; (b) turning right or left through 90 degrees and observing; and (c) walking along the afterimaged corridor. Each task was performed 5 times in a counterbalanced order by each subject. The timed observation period was from the flash to the termination of the long positive afterimage. Subjects reported qualitative changes in the appearance of the afterimage when observing it after turning right or left or during walking. The duration of the afterimage was also greater in those experimental conditions involving movement than in the condition involving immobile observation.