S-shaped diffusion curves can be derived mathematically using social contagion or heterogeneity in the intrinsic tendency to adopt as the chief driver of the diffusion process. I present and evaluate hypotheses as to when either social contagion or heterogeneity will be more pronounced in the diffusion process. I investigate these hypotheses using a meta-analytic test of the q/p ratio from applications of the Bass model to consumer durables. I operationalize various types of social contagion using the GLOBE dimensions of national culture and operationalize heterogeneity using income inequality. Four of the GLOBE cultural dimensions are shown to have a significant effect on new product adoption. The results suggest that social contagion is driven largely by status considerations and social normative pressures. Interestingly, GLOBE’s practices measures vary with the q/p ratio as expected, whereas GLOBE’s values measures do not. Income inequality is also shown to be a significant determinant of the diffusion process. Competing standards are shown to overwhelm both income and culture when such factors are considerations in new product adoption.