The effect of foregone payoffs on underweighting small probability events

Foregone payoffs add information about the outcomes for alternatives that are not chosen. The present paper examines the effect of foregone payoffs on underweighting rare but possible events in repeated choice tasks. Previous studies have not demonstrated any long-lasting effects of foregone payoffs (following repeated presentation of a task) when foregone payoffs do not add much information. The present paper highlights the conditions and the contributing factors for the occurrence of such long-lasting effects. An experimental study compares the effect of foregone payoffs under different degrees of rarity of the negative payoff. It is demonstrated that foregone payoffs increase the selection from risky alternatives with extremely rare and highly negative outcomes, and that this effect does not diminish with repeated presentation of the task. These findings can be summarized using a surprisingly simple reinforcement-learning model. The findings are discussed in the context of the potential long-term effect of social learning. Copyright © 2006 John Wiley & Sons, Ltd.