Melioration behaviour in the Harvard game is reduced by simplifying decision outcomes

摘要

Self-control experiments have previously been highlighted as examples of suboptimal decisionmaking. In one such experiment, the Harvard game, participants make repeated choices betweentwo alternatives. One alternative has a higher immediate pay-off than the other, but with repeatedchoices results in a lower overall pay-off. Preference for the alternative with the higher immediatepay-off seems to be impulsive and will result in a failure to maximize pay-offs. We report an exper-iment that modifies the Harvard game, dividing the pay-off from each choice into two separate con-sequences—the immediate and the historic components. Choosing the alternative with the higherimmediate pay-off ends the session prematurely, leading to a loss of opportunities to earn furtherpay-offs and ultimately to a reduced overall pay-off. This makes it easier for participants to learnthe outcomes of their actions. It also provides the opportunity for a further test of normative decisionmaking by means of one of its most specific and paradoxical predictions—that the truly rational agentshould switch from self-control to impulsivity toward the end of the experimental sessions. Thefinding that participants maximize their expected utility by both overcoming impulsivity and learningto switch implies that melioration behaviour is not due to the lure of impulsivity, but due to thedifficulty of learning which components are included in the pay-off schedules.