A Signal Detection Analysis of the Effects of Workload, Task-Critical and Likelihood Information on Human Alarm Response

Abstract

The purpose of this study was to examine the effects of task-critical and likelihood information on participants' sensitivity and bias to alarm signals under varying levels of workload. Participants performed a complex primary task at the same time they performed a secondary task. Likelihood information was manipulated through the use of either a Binary Alarm System (BAS) or a Likelihood Alarm System (LAS). As expected, task-critical and likelihood information significantly increased participants' sensitivity, and this varied across workload levels. Participants benefited from task-critical information only when they were interacting with the BAS. However, participants benefited from likelihood information regardless of task-critical information, particularly under high-workload conditions. Furthermore, task-critical information increased participants' response bias under low workload, making them less likely to respond to alarm signals. These results demonstrated the superior advantage of an LAS over a traditional BAS and showed support for the use of an LAS as a way to mitigate the cry-wolf effect above and beyond task-critical information.