Money, depletion, and prosociality in the dictator game.

We study the effects of ego depletion, a manipulation which consumes self-control resources, on social preferences in a dictator game. Depleted dictators give considerably less than nondepleted dictators and hence exhibit strong preferences for selfish allocation. In contrast to earlier studies, participants were explicitly paid for completing the ego-depletion task (with either a flat rate or strictly performance-based payment). We studied the dynamics of decisions by repeating the dictator game 12 times (anonymously). Depleted dictators start with much lower offers than nondepleted ones, but, strikingly, offers decrease in time for both groups, and more rapidly so for nondepleted dictators. We conclude that, whereas depleted dictators neglect fairness motives from the very first decision on, nondepleted dictators initially resist the tendency to act selfishly, but eventually become depleted or learn to act selfishly. Hence, pro-social behavior may be short-lived, and ego depletion uncovers the default tendencies for selfishness earlier.