Inducing effective operator control through ecological interface design

Ecological Interface Design (EID) is a theoretical framework for designing interfaces for complex human-machine systems. This article investigates the utility of EID in inducing effective real-time operator control performance during both normal and abnormal conditions. Two interfaces for a thermal-hydraulic process were compared, an EID interface based on physical and functional (P + F) system representations and a more traditional interface based solely on a physical (P) representation. Subjects were given 4 weeks of daily practice with one of the two interfaces before their performance on normal events and unfamiliar faults was evaluated. Under normal conditions, there was no performance difference between the P + F and P interfaces. However. dual task results indicate that the P interface loads more on verbal resources, whereas the P + F interface loads more on spatial resources during normal trials. Furthermore, a process tracing analysis of the fault trials showed that the P + F interface led to faster fault detection and more accurate fault diagnosis. Moreover, the P + F subjects exhibited a more sophisticated and effective set of fault management strategies that are similar to those observed in field studies of experienced operators in complex human-machine systems. In addition, a deficiency of the P + F interface was identified, suggesting a need for integrating historical information with emergent feature displays. Collectively, these findings have significant practical implications for the design of advanced computer interfaces for complex industrial systems. (C) 1996 Academic Press Limited