Matthews Gerald, Reinerman-Jones Lauren E, Barber Daniel J, Abich Julian
Hum Factors. 2015 Feb;57(1):125-43. doi: 10.1177/0018720814539505.
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.
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.
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.
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.
General workload is not well defined psychometrically, although various individual metrics may satisfy conventional criteria for workload assessment.
Practitioners should exercise caution in using multiple metrics that may not correspond well, especially at the level of the individual operator.
开展一项研究，以测试多种工作负荷指标对四种军事监测任务场景中不同认知需求的敏感性，并调查各指标之间的关系。
多种心理生理工作负荷指标对任务因素表现出敏感性。然而，包括它们相互关联程度在内的多个指标的心理测量特性尚未得到充分研究。
150名参与者基于无人地面车辆操作模拟进行了四种任务场景的测试。场景要求进行威胁检测和/或变化检测。使用了单任务和双任务场景。每个场景的工作负荷指标来自脑电图（EEG）、心电图、经颅多普勒超声、功能性近红外和眼动追踪。还评估了主观工作负荷。
几个指标对四种场景的不同需求表现出敏感性。注视持续时间和从脑电图得出的任务负荷指数指标可诊断单任务与双任务表现。其他几个指标区分了两个单任务，但在区分单任务与双任务表现方面效果较差。心理测量分析证实了各个指标的可靠性，但未能识别出任何一般的工作负荷因素。对低工作负荷和高工作负荷条件之间差异分数的分析表明，存在一个由心率变异性和额叶皮层氧合定义的努力因素。
尽管各种单独的指标可能满足工作负荷评估的传统标准，但从心理测量角度来看，一般工作负荷并未得到很好的定义。
从业者在使用可能不太相符的多个指标时应谨慎，尤其是在个体操作员层面。
