UAV Automation : Influence of Task Priorities and Automation Imperfection in a Difficult Surveillance Task

This experiment replicated many aspects of a UAV simulation paradigm in which imperfect automation aids assisted an easy visual monitoring task, while pilots concurrently performed a difficult surveillance task for targets of opportunity, and a primary mission completion task. In that study, changes in the threshold of the automated alert affected both the automated task and the concurrent task in a way suggesting that false-alarm prone automation is more disruptive of both tasks, than is miss-prone automation. In the current study, automation was applied to the difficult surveillance task, and task priority was manipulated. The current results still revealed a greater cost of false-alarm prone automation, again affecting both the automated and concurrent task. Priority instruction tended to produce better performance on the favored task. However with false-alarm prone automation, favoring this task actually reduced its performance. The results are interpreted in terms of the dichotomy between reliance, fostered by miss free automation, and compliance, fostered by false-alarm free automation. These two constructs were found to be only partially independent of each other. Introduction Several previous studies within our laboratory have examined a UAV simulation supported by imperfect automation (Dixon & Wickens 2003; Dixon & Wickens 2004; Wickens, Dixon, Goh & Hammer, 2005; Levinthal & Wickens, in preparation; see also Dixon, McCarley & Wickens, 2005 for a related study). All of these studies have required pilots to perform a primary mission task, navigating to waypoints and doing surveillance at the waypoint, a secondary search task for camouflaged targets of opportunities (TOO task) and another secondary monitoring task, overseeing dynamic system parameters to determine if they are in a normal or “failed” state (system failure, or SF task). In all of these studies the SF task has sometimes been supported by an imperfect alert. Like many alerting tasks in the real world, in which imperfections result from a variety of sources, the threshold, can be adjusted to vary the relative frequency of two different classes of automation “errors”, making either automation misses or automation false alarms more likely. In most real world monitoring tasks designers adjust this alert threshold to minimize misses at the cost of producing more false alarms, on the basis of the assumption that a critical event that is missed, is more damaging to overall system performance, than a non event that is signaled by automation to occur. Across these studies a few general trends have been noted. (1) Automation of high (i.e., 90%) but still imperfect reliability supports better performance than that observed in a manual baseline condition with no automation. (2) When automation reliability falls below about 75%, performance on the SF and TOO task tends to be no better than, and often worse than the baseline level (see also Wickens & Dixon, 2005, in press). (3) Generally, imperfect automation appears to disrupt performance of the automated SF task, more than that of the concurrent TOO task, as if pilots are protecting the latter from the problems associated with the former (see also Wickens & Dixon, 2005). That is, they are treating the concurrent task as “primary” and the automated task as secondary.