Cognitive Fatigue Destabilizes Economic Decision Making Preferences and Strategies

Objective: Individuals often engage in prolonged taxing cognitive activity that leads to cognitive fatigue, which may alter behavior and decision making. This study examined whether cognitive fatigue modulates economic decision making. Methods: Using a between-subjects design, fatigue was induced through 60–90 minutes of a cognitively demanding N-back task; controls watched relaxing videos for a matched duration. Before and after the manipulation, participants completed two incentive-compatible economic decision-making tasks (gains and losses). Analyses focused on uncertainty preferences (risk, ambiguity) quantified as premium values (how gamble valuation deviates from a certain option) and on choice strategies quantified by a metric contrasting reliance on maximizing information (relative expected value, rEV) versus satisficing information (probability of winning, pWIN). Results: The fatigue manipulation produced significantly higher subjective fatigue and effort. Cognitive fatigue did not alter mean uncertainty preferences or informational strategies in gains or losses. Instead, fatigue increased test–retest variability across most economic measures, indicating that cognitive fatigue destabilizes decision-making preferences and strategies, potentially reducing decision quality.