Figural Identity Effects on the Perception of Apparent Movement Produced by a Bistable Multielement Motion Display

The present study investigated the effect of figural identity, and its interaction with temporal presentation variables, on the perception of apparent movement when the preservation of figural identity did not conflict with the perception of a change in stimulus location. The tachistoscopic presentation of bistable multielement motion displays permitted the analysis of the type of motion perceived (either one element or the group of elements), rather than the probability of perceiving motion, which eliminated the conflict between the figural preservation and locational displacement of the stimuli. Twelve subjects nested in each of three stimulus configuration ensembles (N = 36) were presented 5 trials at each of the 54 factorial combinations of three levels of figural conformity (neutral, group movement, or element movement conforming displays), three levels of stimulus exposure duration (100, 200 and 400 msec), and six levels of interstimulus interval (ISI: 5, 20, 35, 50, 65 and 80 msec). The subjects' responses of group or element movement were converted to a percentage of group movement responses for analysis. The results indicated that the figural identity of the stimuli significantly influenced the type of apparent movement perceived. The percentage of group movement responses significantly increased as a monotomic function of increases in the ISI level in the absence of figural identity effects. However, the figural identity effect inhibited the influence of the ISI except at extreme values. The lack of a significant exposure duration effect was attributed to the size and luminance of the stimulus displays. The results were discussed in terms of their implications for contemporary theories of the operation of the visual system in the perception of apparent movement.