UCLA

Human reasoners assemble and connect a variety of information to arrive at a systematic understanding of the world. Coherence and parsimony are fundamental principles that guide this process by constraining the vast hypothesis search space. By taking note of the operations of these principles, we can better understand how real-world beliefs, judgments, and knowledge are formed and why some of them are highly resistant to change. In this dissertation, I present three research projects that involve laypeople’s reasoning about several socially relevant topics. Each of the three projects may be viewed as a different manifestation of a core idea: human reasoners think and act in ways that maximize the perceived coherence between many psychological constructs, including their beliefs, motivations, experiences, internalized social norms, and a positive sense of self. Part 1 analyzes why it is difficult to persuade people holding entrenched beliefs, such as climate change skepticism. Then, a new intervention founded on the principles of coherence and parsimony is tested for its effectiveness in promoting climate actions across the political spectrum. Inspired by the recent #MeToo movement, Part 2 examines the interplay between moral and non-moral judgments about professionals from different fields from the perspective of cognitive consistency theories. Analyses suggest that a decrease in people’s evaluation of professionals in response to the professionals’ moral transgression is driven by a decrease in their liking of the professionals. Part 3 investigates the influence of intergroup dynamics and identity on group-based moral judgments—more specifically, experience of collective guilt and pride, and assignment of responsibility to individuals following harmful or helpful interaction between groups. Two cross- societal experiments suggest that moral judgments made in realistic contexts align with social norms and individuals’ identification with affiliated groups. Implications of these findings for social change and education are discussed.