Modularity of IFE by predictability of the target location
Poster Presentation

Holle Kirchner
Centre de Recherche Cerveau et Cognition, CNRS Toulouse

Hans Colonius
Department of Psychology, Oldenburg University

     Abstract ID Number: 119
     Full text: Not available
     Last modified: March 21, 2005

Abstract
Intersensory facilitation of reaction time is usually considered a mandatory, bottom-up process. However, in several recent studies we showed that saccadic reaction time to a visual-auditory target can be modulated by the predictability of the target location. This only occurred in case of a response conflict between the natural predisposition of the oculomotor system for a visual target and a spatially disparate auditory cue that needed to be considered, either by instruction such as in an auditory prosaccade task [1], or which automatically attracts attention, such as in case of a short temporal offset between the cue and visual target in an antisaccade task [2]. In the present study, when participants were asked to saccade directly to a visual target when accompanied by an auditory cue, with different stimulus onset asynchronies, again reaction times were facilitated as compared to unimodal visual and auditory latencies. If the auditory cue was presented 40 ms after the visual target, bimodal reaction times violated Miller’s race inequality, and this coactivation effect tended to be ordered by the predictability of the target location although no response conflict was involved in the task. We conclude that intersensory facilitation can be modulated by extremely fast top-down control on saccadic eye movements.