| Seven subjects time-shared attention on a Matching to Sample spatial processing task with an auditory target Detection task. Visual stimuli were sample and comparison histograms generated by a C-64 computer, run on the USAF Criterion Test Set Spatial Processing task. Auditory stimuli were 1000 Hz (non-target) and 1500 Hz (target) tones, presented monaurally at 75db against a white background of 53 db. Both tasks were P-300 ERP evoking; there were two difficulty levels of the visual task. Subjects responded manually (button press) to comparison histogram stimuli, and vocally ("yes-go" response) to auditory stimuli. Vocal responses were recognized by a VCP200 (Archer products) voice recognition system. Behavioral (reaction time, percent correct responses, sensitivity) as well as ERP measures (P-300 amplitude and latency) were employed to assess the degree of dual-task interference. Overall, findings on behavioral and ERP measures showed no pattern of significant cross-modal, stage overlap or code defined dual-task interference. These findings support the notion of separate cognitive resources as described in Wicken's (1984, 1990, 1991) Multiple Resource Model. |
