Formal economic models rarely consider the mental conditions of individuals when analyzing their behavior and the decisions they make. In reality, people do this all the time: it seems common sense not to ask friends, family or colleagues to perform important tasks when they’re tired or hungry, and to avoid making important decisions ourselves under those conditions. This intuition has been confirmed by a number of recent studies by psychologists, which show that temporary conditions such as prior performance of a cognitively demanding task or a low level of blood glucose can alter decisions, especially decisions involving the exercise of willpower.
A new IZA Discussion Paper by IZA Visiting Research Fellow Peter J. Kuhn, Michael A. Kuhn and Marie Claire Villeval studies the effects of mental fatigue and sugar consumption on patience a laboratory experiment. In particular, the authors ask whether performing a task that can be considered cognitively depleting affects subsequent intertemporal choices and whether administering a sugar supplement can act as a remedy on the consistency of choices.
Surprisingly, the authors do not find that mental fatigue makes subjects more impulsive. Instead the paper shows that individuals who have recently completed a cognitively demanding task are more patient. Asking the participants to drink either a placebo beverage or a sugared beverage ten minutes prior to the time task also increases the patience of individuals, and does so by raising lower-school test-score subjects’ sensitivity to high prices. These findings suggest that ‘attention-focusing’ tasks and remedying energy deficits may help stimulate the active choice of individuals. This emphasizes the need to help consumers make active and aware choices whenever possible.