Concurrent duration production as a workload measure.

In two experiments the suitability of prospective duration estimation to serve as a secondary task for workload measurement was tested. In the first experiment participants performed either a Stroop task or a card-sorting task with two levels of difficulty. While performing these tasks, participants were also engaged in either a duration-production or a duration-estimation task. Participants in a control group performed the non-temporal tasks without the timing tasks, and rated the level of workload associated with performance of these tasks. It was found that magnitudes of produced durations were highly correlated with subjective workload ratings and with performance indices, without interfering with performance. Similar findings were obtained in a flight simulation conducted by licensed pilots. Again, produced durations were sensitive to concurrent workload levels associated with flight performance and were correlated with subjective ratings of workload obtained by control participants via the Cooper-Harper scale. These findings concur with previous ones reported in the literature. A theoretical basis for these findings is provided and the potential use of concurrent duration production as a measure of workload is discussed.