A closed-loop system for examining psychophysiological measures for adaptive task allocation

A closed-loop system was evaluated for its efficacy in using psychophysiolo gical indexes to moderate workload. Participants were asked to perform eith er 1 or 3 tasks from the Multiattribute Task Battery and complete the NASA Task Load Index after each trial. An electroencephalogram (EEG) was sampled continuously while they performed the tasks, and an EEG index (beta/alpha plus theta) was derived. The system made allocation decisions as a function of the level of operator engagement based on the value of the EEG index. T he results of the study demonstrated that it was possible to moderate an op erator's level of engagement through a closed-loop system driven by the ope rator's own EEC. In addition, the system had a significant impact on behavi oral, subjective, and psychophysiological correlates of workload as task lo ad increased. The theoretical and practical implications of these results f or adaptive automation are discussed.