ABSTRACT
An assessment of the relationship between intersensory bias (visual bias of proprioception and proprioceptive bias of vision) and prism adaptation (negative after-effect, proprioceptive shift, and visual shift) was provided by directly comparing the two phenomena under identical conditions. Three variables were manipulated: Strength of prismatic displacement, realism (“compellingness”) of the visual-proprioceptive relationship, and the presence or absence of vibration of the prism-exposed limb.
Neither limb vibration nor prism strength affected either bias or adaptation. Degree of visual-proprioceptivc compellingness, however, dramatically influenced the strength of intersensory bias (greater bias with high compellingness) but had no effect on any of the three aspects of prism adaptation.
It was concluded from this differential effect that bias and prism adaptation are. at least in some ways, qualitatively different phenomena. Future investigators of prism adaptation are alerted to the importance of taking account of the intersensory bias that is an inevitable concomitant of the situation within which adaptation occurs.
