A TEST OF THE GAIN CONTROL THEORY OF THE MOTION AFTEREFFECT STORAGE PHENOMENON

Thesis (Ph.D.), Department of Psychology, Washington State UniversityThe motion aftereffect (MAE) is a visual illusion that occurs when an individual observes a moving (adapting) pattern for a period of time followed immediately by the viewing of a physically stationary (test) pattern which appears to move in the opposite direction. A variation of the MAE, called storage, temporally separates the adapting pattern and test pattern with an unrelated visual stimulus, leaving a residual MAE. The dominant explanation is gain control theory (van De Grind, Lankheet, & Tao, 2003; van De Grind, van Der Smagt, & Verstraten, 2004; Verstraten, Fredericksen, Grüsser, & van De Grind, 1994), which posits that the residual MAE is the result of gain control mechanisms normalizing the motion sensing cells in the visual system. One method for testing this gain control explanation of the MAE is to employ a diverted-attention manipulation during adaptation, which results in a reduced MAE duration and is generally described as interacting with the gain control mechanisms. This project employed diverted-attention manipulations during MAE storage to test the gain control explanation of MAE storage. The results supported the gain control explanation of the MAE as it pertains to motion adaptation but failed to support the gain control explanation of MAE storage as it exists in the literature. A modification of the gain control explanation of MAE storage that invokes the concept of interference can explain our results.Department of Psychology - Experimental, Washington State Universit