Abstract

The aspects of relative motion and the 2nd-order long-range motion were examined to investigate the interdependency between the two different processes of short-range and long-range apparent motion. Random-dot cinematograms and contoured stimuli were used to help classifying an observed motion into the two different categories of apparent motion following the Braddick's criterion, In the relative mention, the tendency of perceiving the motion direction of a target stimulus relative to that of the frame was greater when the processes involved in the target and frame motion were in the same category than when they were in different categories. This result was interpreted as an indication of the independence of the short-range and the long-range processes, In the 2nd-order long-range motion which was defined as the long-range apparent motion of a stimulus patch dipicted by a pair of random-dot cinematograms, no evidence was found that the output of the short-range process is hierachically fed into the long-range process as an input stimulus for the further processing. In conclusion, the results of the current study suggest that there be neither processing dependency nor hierachical relationship between the mechanisms of short-range and long-range apparnet motion.