Human-centered automation experimental studies of two human-machine interface designs

Lack of information about the automatic system's activity has been suggested to markedly decrease the effectiveness of operator-automation interaction. The Human-Centered Automation Program at the OECD Halden Reactor Project performed two closely related experiments to examine how operators handled two types of automation malfunctions when working from two types of human-machine interfaces: one providing explicit information about the automatic system's activity using graphical and verbal feedback, and one providing only implicit information. The experiments were performed in a full-scale nuclear power plant simulator using licensed operators as subjects. The first experiment demonstrated no clear effect on joint-system performance effectiveness of the human-machine interface manipulation, but pointed to the need for specific changes in the human-machine interface design. The second experiment demonstrated a clear effect on joint-system performance effectiveness of the human-machine interface. Based on the experimental results, a set of recommendations for the design of explicit feedback on the automatic system's activity is suggested.