A Comparison of Experimental Methods to Induce Mental Fatigue.

Appropriate induction of mental fatigue in the lab is imperative for properly investigating the effects of mental fatigue on behavior. In this study, we aimed to (1) identify a task for inducing mental fatigue that is both effective (i.e. sufficiently demanding) and feasible (i.e., sufficiently short in duration), and (2) to assess its effects on boredom, loss of motivation, and sleepiness. Therefore, we compared the following tasks: (1) an individualized TloadDback task (16 minutes), (2) an individualized TloadDback task (32 minutes), (3) an N-back task (32 minutes), and (4) a control task in the form of watching a documentary (32 minutes), using a within-participants design with 30 participants. Subjective and objective outcome measures were used to evaluate levels of fatigue, boredom, motivation and sleepliness pre- and post-task. While all investigated tasks induced mental fatigue, the individualized TloadDback struck the best balance between effectiveness and feasibility and should therefore be preferred in experimental research.