This dissertation tests self-based views of the motivation to reduce cognitive dissonance. Cognitive dissonance describes the state of possessing two or more discrepant attitudes, beliefs, values, or behaviors. When attitudes and behaviors are dissonant, for example, we resolve this conflict by bringing our attitudes in line with our behaviors. The work described in this dissertation bears on a crucial debate in cognitive dissonance: to what extent does this motivation derive from the self?

Self-based views of cognitive dissonance reduction postulate that the motivation to reduce cognitive dissonance requires a distinct kind of self, one that possesses certain capacities and abilities. The current research explores the role of the self in cognitive dissonance reduction by exploring decision-based attitude change in two populations: one that does possess this type of self, and one that does not possess this type of self. Specifically, this research explores decision-based attitude change in young children and capuchin monkeys. Decision-based attitude change has traditionally been understood as evidence of the drive to reduce dissonance: when an individual values an option highly, yet rejects it within the context of a difficult choice, the initial attitude and the rejection behavior are dissonant. Individuals tend to reduce this dissonance by enhancing their perception of the value of the chosen alternative, and devaluing the rejected alternative.

The first chapter explores the type of self that is assumed to be necessary for the motivation to reduce cognitive dissonance, and reviews the relevant literature to establish whether young children and capuchin monkeys possess the type of self required for cognitive dissonance. I argue that capuchin monkeys do not possess the type of self that gives rise to the motivation to reduce cognitive dissonance, and therefore, that they should not exhibit a tendency to devalue rejected options. I also argue that evidence suggests that young children may exhibit this type of self. The following two chapters present evidence that young children and capuchins do indeed devalue rejected options. In the fourth chapter, I investigate whether this tendency in young children actually relies on the self—the lack of affirmation effects on this tendency in children, although a null result, indicates that the self is inessential to the tendency to devalue rejected options. In Chapter Five, I discuss these findings and their implications for how we understand cognitive dissonance in general, and findings that have been attributed to cognitive dissonance reduction in adults.