Origins and Implications of Prosocial Behavior in Early Development.

다국어 초록 (Multilingual Abstract)

Why do people help others, and how can children's prosocial tendencies be leveraged in real-world contexts? In this dissertation, I bring together two lines of research-a project investigating the ontogenetic origins of prosocial behavior in infancy, and two projects investigating how framing preventative health measures as prosocial influences children's reasoning.My project on infant prosociality aims to shed light on the debate over whether people are predisposed to help others or are socialized to be prosocial (see Warneken, 2015; Brownell, 2016) by studying whether young infants will help others utilizing novel eye-tracking methodology. Across two studies (N = 60), infants had the opportunity to help others using their gaze. I found initial evidence for helping behavior among 9-12-month-olds, but further research is needed to rule out alternative explanations.My project investigating children's reasoning about mask-like behaviors aimed to uncover whether emphasizing the prosocial features of novel public health measures would be more effective and moralizing for children, as it is for adults (e.g., Ceylan & Hayran, 2021; Luttrell & Petty, 2020). In two studies (N = 109) conducted using hypothetical vignettes over Zoom, I found that children readily endorse novel protective behaviors, and think about them in moral terms when they are framed as benefiting others. I also examined this effect in a vaccination context using similar methodology. Across two studies (N = 120), I again found that children endorsed the behaviors at high rates, but also found an age effect: younger children thought these behaviors were important regardless of condition, while older children thought of them in moral terms when they were framed as protecting others.Taken together, these three manuscripts constitute important theoretical and methodological contributions. I develop novel ways to investigate how infants and children reason about others. I also shed light on the developmental origins of helping behavior. Finally, I demonstrate how the implications of children's prosociality for their reasoning about public-health measures.