Stimulus dimensionality and temporal repetition

Two experiments involving temporal repetition of tachistoscopically presented visual stnnuh are reported. Experiment I employed an alphabet of four straight lines presented one, two, or four times. Experiment II employed three stimulus sets, such that the stimuli varied in size, brightness, or both, with the forms being presented either once or four times. The Ss made four-choice identification responses. Results indicate that multidomensionality is not a necessary condition for better Identification performance with multiple observations, and that this differential in favor of multiple observations persists after many, many experimental sessions.