THE TIME NEEDED FOR DETECTING CHANGES IN MOTION PATTERN
Three experiments were carried out to measure the time needed to detect changes in a motion pattern. In Experiments 1 and 2, observers were asked to judge whether a change of test pattern or a change of color at the edge of the test field occurred first, while simple response times were examined in Experiment 3. In each experiment, there were five tasks corresponding to five kinds of changes in test pattern: changes of the abrupt appearance (onset) and disappearance (offset) of motion pattern, those of stationary-to-moving and moving-to-stationary patterns, and those of velocity. In all experiments, detections of change in the onset task were faster than those in the stationary-to-moving task, and in the latter, detection time decreased with the increase of velocity. Moreover, in the velocity-change task, detection was faster in the decelerated condition than in the accelerated condition. The results of the offset and moving-to-stationary tasks were inconsistent among experiments.