Fatigue and cognitive control Running Head: MENTAL FATIGUE AND COGNITIVE CONTROL Mental Fatigue and the Control of Cognitive processes: Effects on Perseveration and Task Engagement

Although there are several studies on the effects of mental fatigue on task performance, still much is unknown about the cognitive processes that underlie performance deficits under fatigue. In the current study we test the idea that behavioral manifestations of mental fatigue may be linked to compromised executive control. Executive control refers to the ability to regulate perceptual and motor processes in order to behave in a goal-directed way. In complex tasks such compromised control may become manifest as decreased flexibility to changing tasks circumstances and sub-optimal planning. Mental fatigue in this study is defined as a change in psychophysiological state as the result of sustained performance. In the study we use the Wisconsin Card Sorting Test (WCST) and the Tower of London (TOL), which respectively measure flexibility (e.g perseverative errors) and planning. A simple memory task was used as a control measure. Fatigue was induced through working for two hours on cognitively demanding tasks. The results showed that compared to the non-fatigue group, fatigued participants particularly showed increased perseveration on the WCST. The groups did not differ on general performance on the TOL. However, fatigued participants showed significantly prolonged initial planning time. Fatigue did not affect performance on the simple memory task. These findings indicate compromised executive control under fatigue, which may explain the typical errors and sub-optimal performance that is often found in fatigued people. PsycINFO classification: ?