Proceedings of the Annual Meeting of the Cognitive Science Society

The capacity to continually exert self control appears to become temporarily depleted over time, leading to mental fatigueand self-control failures. Some researchers have proposed that self control requires limited resources which must beperiodically replenished, but no direct evidence supports this theory. An alternative explanation is that mental fatigue isan evolutionarily-adaptive feature for managing motivations, serving to temporarily disincentivize the present course (ortype) of action, thereby redirecting behavior towards other goals that may better serve an individuals evolutionary fitness.Since self control is typically associated with delayed gratification and self-control failures with immediate gratification,mental fatigue may generally encourage immediately-gratifying behavior by temporarily increasing the extent to whichindividuals devalue all future rewards (delay discounting). To test this hypothesis, the present study examines whetherdelay discounting increases for participants who have recently completed a fatiguing task.