Response factors in intermodality localization under conflict conditions

The role of response modality in resolving visual-proprioceptive spatial conflict was evaluated. Subjects responded to either the felt or the seen locations of their forefingers viewed through an ll-deg laterally displacing wedge prism. Four response conditions were used: pointing with the contralateral hand either (1) during target presentation or (2) after target offset, (3)pointing with the ipsilateral (target) hand after target offset, and (4) making a visual localization response after target offset. Using the contralateral hand produced a compromise between vision and proprioception that fell about two-thirds of the way toward the optical location. Using the visual response increased visual influence. Using the ipsilateral response decreased visual influence. It was concluded that visual-proprioceptive interaction in spatial localization is not immune to response modality effects. A possible explanation of the response modality effect, based on differential attention, is discussed.