The direction of walking-but not throwing or kicking-is adapted by optic flow

Abstract

Optic flow is known to adapt the direction of walking, but the locus of adaptation remains unknown. The effect could be due to realignment of anatomical eye, head, trunk, and leg coordinate frames or to recalibration of a functional mapping from the visual direction of the target to the direction of locomotion. We tested whether adaptation of walking to a target, with optic flow displaced by 10°, transfers to facing, throwing, and kicking a ball to the target. A negative aftereffect for initial walking direction failed to transfer to head orientation or throwing or kicking direction. Thus, participants effectively threw or kicked the ball to the target, and then walked in another direction to retrieve it. These findings are consistent with recalibration of a task-specific visuo-locomotor mapping, revealing a functional level of organization in perception and action. © 2010 The Author(s).