The role of the driver's motivational state in eliciting fatigue-related decrements in driving performance has been largely neglected by researchers. However, its importance has been highlighted by McDonald (1984), who argues for motivational explanations for impairments in decision-making, judgement of risk and attention when driving is prolonged. Studies of fatigue in contexts other than driving also indicate that de-motivation and apathy are primary symptoms of fatigue, which are expressed in reduced effort on the task at hand (Craig & Cooper, 1992). Hence the aim of the present study was to examine the effect of a motivational manipulation in reversing or reducing fatigue-related decrements in simulated driving performance. The authors also aimed to examine implications of motivational change for the design and use of in-vehicle countermeasures to driver fatigue. As in the Desmond and Matthews (1996) study, drivers performed both a fatiguing drive, in the first part of which a fatigue induction procedure was added to the primary task of driving, and a control drive without fatigue induction. The effects of the fatigue manipulation on drivers' subjective states were assessed by the selection of subjective measures used in the previous study. The motivational manipulation, an instruction that driving skill was under assessment, appeared in early and late stages of control and fatigue drives. Control of the lateral position of the vehicle was assessed before, during and after the instruction.
Abstract