EFFECTS OF SLEEP-DEPRIVATION AND USER-INTERFACE ON COMPLEX PERFORMANCE - A MULTILEVEL ANALYSIS OF COMPENSATORY CONTROL

This study was carried out to test the compensatory control model, whi ch predicts performance maintenance under stress at the expense of eff ort and increased selectivity. It examined the effects of sleep depriv ation on performance in an automated process control task based on a s implified life support system with two types of operator control panel interface: machine centered (M-C), in which access to the system was scheduled by the computer, and human-centered (H-C), in which access w as ad-lib. The task environment also permitted the analysis of changes in strategy and in subsidiary activities (alarm reaction time, prospe ctive memory). In a 2 x 2 repeated-measures design, 16 participants ca rried out the task with each interface after both normal sleep and one night of sleep deprivation (SD). No effects of SD were observed on pr imary task performance. As predicted, SD effects were confined to stra tegy changes and subsidiary task impairment and occurred only under th e (low control) M-C interface. Subjective effort was increased under S D, with greater increases of effort associated with high levels of per formance protection. The findings provide strong evidence in favor of the compensatory control model and argue for the use of complex, multi level tasks in the analysis of performance under stress. Actual or pot ential applications include the development of more sensitive performa nce-testing systems based on multilevel analysis of decrement, and the design of interfaces for shift work and other suboptimal work conditi ons.