Task-related effort - distinguishing boredom- and difficulty-related effort via electrodermal activity

Exerting effort is central to human performance, with the sources of effort varying across tasks. While traditionally linked to task difficulty, effort may also be required to cope with task-induced boredom. Here, we investigate the temporal dynamics of boredom- and task-difficulty-related effort during cognitive tasks and investigate their physiological correlates using electrodermal activity (EDA). Additionally, we explore whether the effort invested in cognitive tasks affects performance in subsequent physical tasks. Ninety-five participants completed two Stroop tasks (easy, hard) while repeatedly rating their experiences of boredom, task difficulty, related efforts, and fatigue. Each Stroop task was followed by a handgrip task. Results revealed distinct temporal patterns, with boredom, boredom-related effort and fatigue increasing over time, while task difficulty and difficulty-related effort decreased. The easy Stroop elicited greater boredom and fatigue, whereas performing the hard Stroop resulted in higher task difficulty and difficulty-related effort, suggesting that enduring boredom may be more fatiguing than managing task difficulty. Distinct physiological patterns were observed for our effort variables: in the easy Stroop, EDA was positively associated with boredom-related effort but negatively associated with difficulty-related effort. No significant effects were observed in the hard Stroop. Neither difficulty- nor boredom-related effort influenced handgrip performance. Thus, no evidence for ego depletion or mental fatigue effects was found. By differentiating the psychological and physiological correlates of boredom- and difficulty-related effort, this study advances the understanding of the multifaceted nature of effort required during tasks and underscores the role of boredom in shaping cognitive and physiological responses during task performance.