Manipulation specific effects of mental fatigue: evidence from novelty processing and simulated driving.

Mental fatigue has a wide range of effects on cognitive, behavioral, and motivational measures. It can be expected that specific effects in which fatigue becomes manifest is dependent on the nature of fatigue-inducing activity (e.g., level of control and working memory demands). This study examined how fatigue caused by tasks that differ on the level of working memory demands (0-Back, 2-Back) affects brain function (novelty processing, P3a) and performance (driving). Results showed that fatigue did not affect driving performance. Fatigue did reduce P3a amplitude, but only after 2-Back. P3a was also reduced during driving. The effects of fatigue and driving on P3a were additive. In summary, both driving and fatigue reduced P3a amplitude. Driving effects were always present. Fatigue effects on novelty processing were dependent on the cognitive demands of the fatigue-inducing task.