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

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