Monitoring dynamic processes with alphanumeric and graphic displays

Three experiments assessed the relative efficiency of graphic and tabular displays for detecting changes in periodic sine functions, simulating a dynamic process. In all three experiments, line graphs had an advantage over tables for response times, for correct detections and identifications, and for false alarms. However, this advantage depended on the type of change that indicated a malfunction. The largest difference between the displays was evident for the detection of changes in a function’s frequency and smaller differences were found for the detection of changes in amplitude and intercept. Results also indicated that participants adapted their detection methods to the types of possible changes. The findings demonstrate the value of graphic displays for process control and substantiate the claim that graphic displays have an advantage when the displayed information has inherent structure and when the task requires the use of this structure. In addition, task performance was the subject of adaptive changes, which depend on the context in which the task is performed.