Mood effects on dominated choices: Positive mood induces departures from logical rules

In two studies, we investigated the role of mood states in dominated behavioral choices. Past research has shown that mood effects on judgment and decision-making can be pervasive. Yet, the role of mood in dominated choices has so far been neglected. The present research represents a first empirical examination of mood effects on dominated choices. We measured (Study 1) or manipulated (Study 2) mood states in participants who made a series of choices in a gambling game. In this choice task without trade-offs, participants were provided with information about the outcomes and probabilities associated with each choice option. The strategy to maximize the expected mean outcome implied the application of a straightforward and logical rule: Always choose the dominant option with the highest expected value. It has been argued in the literature that mood should have little or no impact when preferences are clear or strong. Still, we expected that mood states would affect even these dominated choices, building on previous work that showed that positive mood states enhance flexibility, creativity, and explorative behavior. The results showed that decisions made in a happier mood were less often in accordance with the logical rule than decisions made in a sadder mood. To conclude, happier mood states are associated to a lesser extent with decisions in accordance with a rule-based strategy that maximizes expected mean outcomes in dominated choices. Copyright (C) 2010 John Wiley & Sons, Ltd.