Abstract of the

Many previous studies of both behavioral and physiological correlates of cogn~t~ve workload have burdened subJects w~th a contrived secondary task ~n order to assess the workload of a pr~mary task. The present study invest~gated event-related potent~al (ERP) indices of workload in a single task paradigm. Subjects mon~tored changing digital readouts for values that went "out-of-bounds. " The amplat.ude of a long-latency pos i ta.va.-ty in the ERPs elicited by readout changes increased with the number of readouts being monitored. This effect of workload on ERPs is reported, along with plans for addit~onal analyses to address theoretical implications. Despite considerable research aimed at developing reliable measures of the cognitive workload experienced by human operators in complex man-mach~ne systems (see Frazier & Crombie, 1982), the assessment of operator workload in realistic settings is still problem-atic. Subjective ratings of workload are usefu