The role of stationary and dynamic test patterns in rapid forms of motion after-effect

Subsecond adaptation to directional motion can induce a rapid form of motion after-effect (rMAE). Unlike the characteristics of the classic motion after-effect (MAE), produced by adaptation of several seconds or minutes, the properties of the rMAE have been less well explored. In a series of experiments, we assessed the role of stationary and dynamic test patterns (counterphase flickering gratings) in generating rMAE. In particular, we varied the duration, temporal frequency, and spatial phase of the adapting stimuli. Our results show that rMAE is only generated by dynamic test patterns, exhibiting a strong dependence on the adaptation duration and temporal frequency but not on the spatial phase. Similarly to the classic dynamic MAE, the temporal frequency tuning of the dynamic rMAE suggests the involvement of both low-pass and band-pass visual channels. Unexpectedly, our results do not show evidence for static rMAE. We speculate that a stationary test pattern presented immediately (or very soon) after the adapting pattern could interfere with the effects of adaptation by disrupting weak motion signals that arise from adapted and unadapted motion detectors (Ledgeway & Smith, 1994a, 1994b).