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Abstract

Vestibular activity, motor command efference copies, and proprioception, among others, contribute to self-motion perception. According to Durgin et al. (2005) these sources are recalibrated when they are in conflict with the global self-motion percept. We tested this hypothesis by having participants walk blindfolded on a circular treadmill, under different conditions which varied in speed and direction of treadmill rotation independent of the participants’ walking speed. Recalibration was assessed with two tasks. Participants either stood in place and judged when the treadmill had rotated 360º (passive task), or walked 360º on a stationary treadmill (active task). Durgin’s, results indicate that participants should undershoot relative to pretest performance in the active task when the treadmill had rotated in the walking direction and that they should overshoot when it was moving against the walking direction. For the passive task the opposite pattern was predicted. However, we obtained an overshoot in both tasks increasing with the duration of adaptation. One possible source for the difference between Durgin’s and our results might be the availability of visual information that his participants had at the start of pre/posttests about their location in space. In our study disorientation might have accumulated leading to an increasing overshoot.