Abstract
When riding in a car, we experience a mismatch between optic flow and self-produced locomotor activity. In this circumstance, we do not experience a subsequent visuomotor adaptation, perhaps due to the absence of locomotor movement. Note, however, that a mismatch produced by pairing locomotion with an absence of optic flow – in this case, caused by wearing a blindfold – does induce and aftereffect (Durgin & Pelah, 1999). The present research investigated what sort of action / optic flow pairings are required to evoke a visuomotor adaptation. The study employed a 2 x 4 design in which one half of the participants experienced optic flow at 3 mph, and one half of the participants experienced zero optic flow. During this time, participants performed one of 4 actions: walking on a treadmill at 3 mph, walking in place, riding a stationary bicycle, or standing still. For each participant, we obtained pre- and post- measures of forward drift during a blind marching in place task. We found that pairing zero optical flow with treadmill walking was the only condition evoking a reliable visual motor adaptation. We conclude that effort to self locomote, coupled with a mismatch of optic flow, is required in order to establish a visuomotor aftereffect.