Weather to Help: How Sunlight (and the Stock Market) Influence Prosocial Behavior

Scholars have shown that sunlight increases riskless prosocial behavior, arguing that sunlight increases positive affect which increases prosocial behavior. This is consistent with “rational altruism”: individuals with more psychological (positive-affect) resources will “spend” more resources on prosocial behavior. In contrast, we propose “affective gamble theory” (AGT): risky (but not riskless) prosocial behaviors are construed as “affective gambles” and will follow prospect-theory altruism (not rational altruism). AGT predicts both positive-affect events and negative-affect events can decrease risky prosocial behavior. We test AGT by conceptualizing sunlight as a positive-affect-inducing event (Study 1), stock market rises (“good news”) as positive-affect-inducing events (Study 2) and stock market falls (“bad news”) as negative-affect-inducing events (Study 2). Sunlight, good news, and bad news all decrease risky prosocial behavior, consistent with AGT.