Abstract
Action-specific perception researchers claim that action information causes a difference in perception of task relevant stimuli. One example of this is the pong paradigm in which participants attempt to block a ball and rate the speed of the ball. When participants use a small paddle, the ball is rated as moving faster than when they use a large paddle (hard vs. easy blocking conditions). One question that arises from the claim that action affects perception is "how much does action affect perception?" The current research explores this question in the pong paradigm by pitting action information against an optical cue for motion using the method of constant stimuli. Over the course of 3 experiments and 1 replication, participants had to block a 1 cm diameter ball moving between 26.2 cm/s and 74.2 cm/s with a 1.86 cm paddle or a 9.28 cm paddle against a background of moving dots which either moved in the same direction (+) or opposite direction (-) of the ball. The results of these experiments demonstrate that the effect of reducing the paddle length by 7.42 cm is equivalent to changing the background motion of the dots from -19.13 cm/s to 19.13 cm/s. Both background motion against the target and the small paddle made the ball appear approximately 4 cm/s faster (8.3% increase in speed) compared to background motion moving in the same direction and the large paddle respectively. These results contextualize how big of an impact action information has on vision. In baseball, an 8% increase in the speed of a fastball is achieved by shifting pitcher grip, and this change can be the difference between a strike or not. Action information does have a practically significant impact on motion perception.
Meeting abstract presented at VSS 2016