UC San Diego

Conditional statements often imply meanings that go beyond their literal content. Consider “If you mow the lawn, you will receive $5.” Logically, the sentence says only that mowing suffices for the reward and leaves open whether the money might be earned another way. Yet listeners routinely strengthen it into a biconditional, treating the stated condition as the only route to the consequent. This pragmatic inference, known as Conditional Perfection (CP), is the central phenomenon investigated in this dissertation. Across three chapters, I ask how listeners arrive at these strengthened interpretations, what determines whether a conditional is understood literally or pragmatically, and how this ability develops in children. Most accounts treat perfection like scalar implicature, derived by generating and negating a set of stronger lexical alternatives. I argue instead that it arises from a more global exhaustivity assumption that does not depend on a fixed set of lexical alternatives, and that this difference has consequences for how CP is computed, when it arises, and how it develops. Chapter 1 examines the time course of perfection and finds that literal interpretations take longer to reach than perfected ones, and that cognitive load makes listeners more, not less, likely to perfect. CP is the first interpretation listeners access, and the literal reading is reached with effort only when context requires it. Chapter 2 investigates the contextual factors that modulate perfection and shows that both the Question Under Discussion and the speaker's knowledge influence which alternatives count as relevant and so whether the conditional is perfected. Chapter 3 extends the account to development. In two experiments, children as young as four interpret conditionals literally when alternative antecedents are made salient or when context renders a perfected reading infelicitous. Earlier reports of children's difficulty, I argue, reflect sparse contextual support rather than a deficit in the underlying capacity. Together, these findings suggest that conditional perfection arises through an assumption of exhaustivity and is readily available to adults and children alike. What context modulates, and what development supports, is the capacity to determine which alternatives count as relevant in a given conversation, and which do not.