Concept of time-on-task induced fatigue in lay people: a survey-based examination using situational judgement paradigm

• Laypeople's concepts of mental fatigue were examined using situational scenarios. • Scenarios compared fatigue perceptions across workload and task types. • Laypeople link fatigue mainly to boredom and energy demands. • Motivation shape lay fatigue perceptions. • Non-scientific views are diverse regarding the potential causes of fatigue. Mental fatigue is a common subjective experience, often caused by prolonged mental workload (i.e. Time-on-Task). While there are several scientific theories about the nature and causes of fatigue induced by Time-on-Task, no studies have examined how these scientific theories are consistent with lay persons’ views on fatigue. Therefore, across two studies using situational judgment tasks, we examined how participants rated imagined work scenarios on various fatigue-related factors. Study 1 compared low and high workload office tasks, while Study 2 compared two different work situations (parking attendant and warehouse worker), with samples matched on key demographics. Participants rated which task characteristics are involved, and most likely cause fatigue. Participants’ mood states were also assessed, namely anxiety, depression, and fatigue catastrophizing. Results revealed that participants consistently view fatigue as a multifaceted experience, primarily linked to boredom, low motivation, drowsiness, and high energy demands. Notably, perceived workload, stress, and task difficulty did not affect fatigue ratings. In both studies two main factors emerged in the ratings: one related to energetic aspects, and another related to boredom, discouragement, and low motivation. Participants ‘own mood states did not relate to their ratings of the scenarios. In general, the results suggest that non-scientific views are also diverse regarding the potential causes of fatigue but overlap with scientific views.