Many modern systems, such as advanced aircraft, are so complex that a human cannot control the system without the assistance of automation. The author performed an experiment in which a human, working in conjunction with an automated signal detection device, monitored a system for abnormal states. The human and the automated alarm monitored sets of information that were either dependent, partially independent, or independent of each other. The response criteria of the alarm and human were manipulated. The participants concurrently performed either an easy or difficult tracking task as a load task. The results indicate that system sensitivity decreases as the sets of information become increasingly dependent on each other. The benefits of the alarm did not always outweigh its costs, especially in the more dependent conditions, which are probably more characteristic of real-life situations.
Abstract