Behavioral indicators - an approach for assessing nuclear control room operators’ excessive cognitive workload?

Cognitive workload that deteriorates the control room team’s performance is a central topic for human-technology design and evaluation. However, while stated as an essential research topic, the literature provides few studies investigating the excessive cognitive workload of complex dynamic human-system work. Multiple techniques have been developed to sample workload. Still, they all struggle to determine the nature of excessive workload, capturing change but leaving the interpretation to the investigator. To advance the measurement of excessive cognitive workload of complex work, this paper proposes to investigate behavioral indicators. Behavioral-based methods differ from performance measures as they concentrate on the operator's behavior rather than the outcome of the actions. The information embedded in the operator’s behavior may not directly reflect the outcome of the task. The paper proposes indicator categories in terms of task prioritization, work practices and low-level behavior. The approach implies developing an understanding of how control room teams adapt to and manage task load and how operators are affected by high workload – for the identification of indicators, and for the development and validation of measures from these cognitive workload indicators. The paper presents an initial review of simulator studies identifying adaption such as down-prioritizing secondary tasks, reducing attention to global process overview, asking for or providing team support on task demand, reducing verification of work, and delayed response in communication. Furthermore, we briefly consider the technical and staffing requirements necessary to support these measures.