Firstborns buy better for the greater good: Birth order differences in green consumption values

Despite multiple studies on the role of birth order in shaping human personality, marketing literature has largely neglected its role in shaping consumer behavior. We conducted a high-powered birth-order study on several consumption-related measures (N_{main analyses} = 1358), which consistently enabled us to detect effect sizes even smaller than d = 0.20 with a power of 0.90. Participants filled out scales measuring susceptibility to normative interpersonal influence, the need for uniqueness, and the tendency to express the value of environmental protection through purchases and consumption behaviors. At a general level, we did not find any support for the notion that firstborns (vs. laterborns) are more susceptible to normative interpersonal influence or have a lower need for uniqueness. However, we found robust results regarding green consumption values, with firstborns valuing sustainability and proenvironmental consumption more than laterborns. Considering the number of consumers with siblings in the world and bearing in mind the ease with which birth-order data can be collected, these findings may have implications for activities aimed at mitigating climate change. However, the novel nature of our results calls for appropriate caution.