Motion adaptation does not depend on attention to the adaptor.

Prolonged inspection of moving stimuli causes stationary stimuli to appear moving in the opposite direction to the adapting stimulus (the Waterfall effect). It has been claimed that distracting the viewer's attention from the adapting stimulus by a secondary task reduces the strength of adaptation. However, the method used to show the effect of distraction (the duration of the aftereffect) is potentially susceptible to bias. The experiments reported here show no effect in genuinely naïve subjects, or in experienced observers using a variety of cancellation procedures to measure the effect.