Descriptions of a dynamic warning system usually assign the system certain diagnostic values. Operators should adjust their responses to these values when considering the output of the system for their decisions. This approach, however, is not necessarily appropriate for complex systems that are controlled by human operators. In these situations, the operators' actions are likely to change the frequency of events that should trigger a warning. Consequently, the operator will change the predictive value of a warning system that is imperfectly correlated with the monitored events. In general, its diagnostic value decreases for better operators. This phenomenon is shown by the example of binary warnings about binary events, and an empirical demonstration of the phenomenon is provided in an experimental study of a process control task. Actual or potential applications of this research are provided and discussed. (Author/publisher)
Abstract