Asymmetric visual prism adaptation and intermanual transfer.

The authors hypothesized that failure of visual adaptation to transfer from an individual's exposed right hand to the unexposed left hand arises from hemispheric asymmetry in eye-hand coordination, such that the dominant eye-right-hand system is specialized for action in the right body space. Groups received combinations of exposed dominant or nondominant hands and right or left prismatic displacement. Following prism exposure (terminal feedback), the authors measured aftereffects for proprioceptive straight-ahead and straight-ahead target pointing for both hands. They measured visual straight-ahead aftereffects, starting from the left and right hemispaces. Results were consistent with the prediction: Visual adaptation transfer and additivity occurred when the nondominant left hand was exposed but not when the dominant right hand was exposed. Visual straight-ahead asymmetry appeared when the dominant right hand was exposed to leftward displacement. The authors discuss the implications for the general theory of prism adaptation.