@article{ref1,
title="The psychometrics of mental workload: multiple measures are sensitive but divergent",
journal="Human factors",
year="2015",
author="Matthews, Gerald and Reinerman-Jones, Lauren E. and Barber, Daniel J. and Abich, Julian",
volume="57",
number="1",
pages="125-143",
abstract="OBJECTIVE: A study was run to test the sensitivity of multiple workload indices to the differing cognitive demands of four military monitoring task scenarios and to investigate relationships between indices. <br><br>BACKGROUND: Various psychophysiological indices of mental workload exhibit sensitivity to task factors. However, the psychometric properties of multiple indices, including the extent to which they intercorrelate, have not been adequately investigated. <br><br>METHOD: One hundred fifty participants performed in four task scenarios based on a simulation of unmanned ground vehicle operation. Scenarios required threat detection and/or change detection. Both single- and dual-task scenarios were used. Workload metrics for each scenario were derived from the electroencephalogram (EEG), electrocardiogram, transcranial Doppler sonography, functional near infrared, and eye tracking. Subjective workload was also assessed. <br><br>RESULTS: Several metrics showed sensitivity to the differing demands of the four scenarios. Eye fixation duration and the Task Load Index metric derived from EEG were diagnostic of single-versus dual-task performance. Several other metrics differentiated the two single tasks but were less effective in differentiating single- from dual-task performance. Psychometric analyses confirmed the reliability of individual metrics but failed to identify any general workload factor. An analysis of difference scores between low- and high-workload conditions suggested an effort factor defined by heart rate variability and frontal cortex oxygenation. <br><br>CONCLUSIONS: General workload is not well defined psychometrically, although various individual metrics may satisfy conventional criteria for workload assessment. APPLICATION: Practitioners should exercise caution in using multiple metrics that may not correspond well, especially at the level of the individual operator.<p /> <p>Language: en</p>",
language="en",
issn="0018-7208",
doi="",
url="http://dx.doi.org/"
}