title: [Global matching and local matching in perceiving velocity changes].
abstract: Two experiments were conducted to examine the processes of perceiving velocity changes of visual stimuli which were gradually accelerated. In Exp. I, using a rotating pattern of luminous spots as moving stimuli, the time required of the subject to perceive a velocity change was measured in slow, medium and fast positively accelerating conditions. Irrespective of the accelerating rates, subjects tended to respond at the time the velocity difference attained to a constant value. In Exp. II, with the same moving pattern but presented only for a predetermined duration, subjects were asked to judge if there was a velocity change or not. The results showed that the slower was the acceleration, the larger were the velocity differences required of the subject to notice the velocity change. Based upon these results, the velocity change perception was discussed in terms of global and local matching processes.
mesh_terms: D000054:Acceleration; D000328:Adult; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D011601:Psychophysics