Task-induced fatigue states and simulated driving performance

Abstract

States of fatigue are implicated in driver impairment and motor vehicle accidents. This article reports two studies investigating two possible mechanisms for performance impairment: (1) loss of attentional resources; and (2) active regulation of matching effort to task demands. The first hypothesis predicts that fatigue effects will be accentuated by high task demands, but the second hypothesis predicts that fatigue effects will be strongest in "underload" conditions. In two studies, drivers performed a stimulated driving task, in which task demands were manipulated by varying road curvature. In a "fatigue induction" condition, the early part of the drive was occupied by performance of a demanding secondary task concurrently with driving, after which the concurrent task ceased. Post-induction driving performance was compared with a control condition in which drivers were not exposed to the induction. In both studies, the fatigue induction elicited various subjective fatigue and stress symptoms, and also raised reported workload. Fatigue effects on vehicle control and signal detection were assessed during and after the fatigue induction. The fatigue induction increased heading error, reduced steering activity, and, in the second study, reduced perceptual sensitivity on a secondary detection task. These effects were confined to driving on straight rather than on curved road sections, consistent with the effort regulation hypothesis. The second study showed that fatigue effects were moderated by a motivational manipulation. Results are interpreted within a control model, such that task-induced fatigue may reduce awareness of performance impairment, rather than reluctance or inability to mobilize compensatory effort following detection of impairment.

An Integrated Agent Model Addressing Situation Awareness and Functional State in Decision Making

“…as a consequence of low effort investment) may result in an impairment of effort regulation [3]. This is confirmed by Matthews and Desmond [8] who found an effort reduction as a consequence of a reduced awareness of performance impairment with the increase of fatigue.…”

Diagnostic Methods for Predicting Performance Impairment Associated With Combat Stress

“…However, when the perceived workload of the task is high, participants must mobilize additional effort to maintain safety and performance, and this additional effort may focus attention on the task, and mitigate the effects of stress on performance. Previous driver simulator studies have found that stress (Matthews, 1996) and fatigue (Matthews & Desmond, 2002) inductions have more serious adverse effects on vehicle control and attention to hazards during straight sections of roadway, as opposed to curved sections of roadway. These findings support an effort regulation model of stress and performance; contrary to resource theory, stress and fatigue may be most damaging when workload is low.…”

“…One such task, of military relevance, is vehicle driving. Our previous studies (e.g., Matthews & Desmond, 2002) have shown that the driver's ability to control the vehicle while also monitoring for target stimuli may be impaired following a period of prolonged high workload. The aim for this study was to investigate subjective predictors of performance deficit during simulated vehicle operation, as a precursor to a later study using the TCD.…”

“…The effort regulation hypothesis attributes performance impairments to a failure to match effort to environmental task demands (Hancock & Warm, 1989). Such performance impairment may be due to a lowering of performance standards (Hockey, 1997), or it may be a consequence of insufficient performance monitoring and lack of awareness of impairment (Matthews & Desmond, 2002). In driving, when the perceived workload of a task is low, drivers may under-estimate the difficulty of current driving conditions, leading them to apply less effort to the task.…”

Drivers’ Reliance on Lane-Keeping Assistance Systems as a Function of the Level of Assistance

“…Two forms of latent performance decrements were supposed to play a role in this study: compensatory costs and subsidiary task failures (Hockey, 1997). In previous driving studies, measures of lateral vehicle control (heading error, steering reversals) have been shown sensitive for drivers' strategic regulation of mental effort (Fairclough, 2001;Matthews & Desmond, 2002). However, lateral control measures were confounded by the effects of the lane keeping assistance systems in this study and could not be used as clear indicators for drivers' strategic regulation of mental effort.…”