Abstract
Neuropsychological investigations have demonstrated that attention is composed of multiple interacting subsystems mediated by distinct neurological substrates. The covert-orienting paradigm has been used successfully to differentiate between selective attention and alerting within the posterior spatial orienting system. The purpose of this study was to examine the impact of a secondary task on selective attention and alerting. A simulated driving task and an orienting task were administered under both single and dual-task conditions. In the driving task, a staircase procedure was used to adjust the amplitude of the “wind shear” applied to the car, such that observers were able to maintain the car in the center lane 90% of the time. In the orienting task, reaction time to identify the spatial location in which a target appeared was measured. Observers fixated on a point flanked by two boxes at the horizon of the center lane while the car was stationary. One, both, or neither of the boxes brightened prior to the presentation of a target. RT differences between the valid and invalid cue conditions served as an index of selective attention, and RT differences between the double and no cue conditions served as an index of the alerting effect. In the dual-task, observers performed the orienting task with the driving task, keeping the amplitude fixed to the individual observer's 90% criterion level. Observers showed significant selective attention and alerting effects in the spatial orienting task under both single and dual-task conditions. The alerting effect, but not the selective attention effect, increased significantly during dual-task. These results indicate that within a covert-orienting paradigm, dual-task conditions selectively disrupt the alerting component within the posterior attentional system.
Supported by NIH AG15375-01.