Personality and multiple dimensions of task-induced fatigue: a study of simulated driving

This article reports the development of a multidimensional measure of subjective fatigue states, and its associations with personality in an experimentally-controlled context. In a study of simulated driving, 256 subjects completed a new 24-item fatigue scale as well as other subjective state measures, before and after performing a fatiguing drive. An item factor analysis identified four correlated dimensions: visual fatigue, muscular fatigue, boredom and malaise. The scales were sensitive to increased fatigue following the fatiguing drive, and showed a high degree of internal consistency. The fatigue scales correlated substantially with general state measures, such as mood and motivation. A factor analysis of fatigue and other state scales identified second-order factors of task disengagement (including boredom), physical fatigue (including the other three fatigue scales), and a distress factor. The fatigue scale was also correlated with the EPQ-R and with a measure of traits related specifically to driving, the Driving Behaviour Inventory (DBI), which includes a Fatigue Proneness scale. Bivariate and multivariate analyses showed that Fatigue Proneness was the strongest single predictor of task-induced fatigue symptoms, as predicted from an interactionist analysis of relationships between traits and states. However, the relationship between traits and states associated with fatigue was complex, and other EPQ-R and DBI traits, including neuroticism, were independently associated with fatigue.