Probing sustained attention and fatigue across the lifespan

Trait fatigues reflects tiredness that persists throughout a prolonged period, whereas state fatigue is defined to be short term after “intense and/or prolonged effort”. We investigated the impact of prolonged sustained attention (using the SART task) on both trait and state fatigue levels in the general population. A JsPsych online version of the SART task was undertaken by 115 participants, stratified across the whole adult lifespan. While pre-task trait fatigue was a strong indicator of the initial state fatigue levels, undergoing the task itself induced an increase in reported subjective state fatigue, as well as reduced energy. Consistent with this finding, greater subjective state fatigue levels were associated with reduced accuracy. In addition, age was the best predictor of inter-participant accuracy (the older the participants, the greater the accuracy), and learning (i.e., task duration reducing reaction times). Moreover, a ceiling effect occurred where participants with higher trait fatigue did not experience greater state fatigue changes relative to those with low trait scores. In summary, we found improved accuracy in older adults, as well as a tight coupling between state fatigue and SART performance decline (in an online environment). The findings warrant further investigation into fatigue as a dynamic, task-dependent state and into SART task performance as an objective measure and inducer of fatigue.