Human Redundancy as Safety Measure in Automation Monitoring

Abstract

The present study addresses effects of human redundancy on automation monitoring performance. Fourty-six participants performed a multi-task, consisting of three sub-tasks which simulate basic demands of operators in a chemical plant. One of the tasks involved the monitoring of an automated process. Participants were randomly assigned to three groups: (1) “Non-Redundant”: participants worked on all tasks alone. (2) “Redundant”: participants were informed that a second crewmate would work in parallel on the monitoring task. (3) “Redundant-Feedback”: like the “redundant” condition with the additional information that crewmembers’ individual monitoring performance would be tracked and fed back. Results provide evidence of social loafing effects in monitoring performance. Participants in the “redundant” condition cross-checked the automation significantly less than participants in the other groups. Moreover they were more prone to miss automation failures which occurred surprisingly. The anticipation that individual performance will be tracked and fed back after the task in the “redundant-feedback” group reduced this effect. The results suggest that human redundancy does not necessarily constitute an effective measure for enhancing reliability of automation monitoring and that expected positive effects can at least partially be off-set by a sort of social-loafing effect.