Against omission bias: Adolescents prefer commissions in vaccination decision-making

People prefer choosing omission rather than commission when the risks of negative outcomes are similar, which is known as omission bias. While adults exhibit omission bias in various contexts, whether adolescents exhibit omission bias in decision-making remains a matter of debate. The present study examined the choice between commission and omission of early-to-middle adolescents (n = 123) and young adults (n = 131) in a classic vaccination decision-making context. The results revealed that adolescents were more inclined to commission, especially when the risks of negative outcomes for both choices were equal. Drift diffusion model analysis revealed that compared to young adults, adolescents had a similar drift rate but a much lower threshold separation. These findings suggest that adolescents had a preference for commission in decision-making, which might motivate adolescents to engage in positive risk-taking and gain social experience.