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Matthew A. Turner
Social Sciences Division
Stanford Doerr School of Sustainability
Stanford University

Group-level homophily in metapopulation social networks can optimize the diffusion of innovations

The diffusion of innovations drives economic success, social progress, ecological sustainability, and public health. Various studies suggest that asymmetric homophilous mixing in metapopulations (i.e., populations composed of groups) can promote the diffusion of innovations. Asymmetric homophilous mixing means interaction partners preferentially come from within one’s own group, depending on each group’s homophily level. Currently, we lack a systematic understanding of how asymmetric group-level homophily affects the diffusion of innovations. To address this, we develop an agent-based model where individuals are members of a minority or majority group, defined by population size. Group-level homophily specifies a random social network that structures social learning. We find that simulated minority subpopulations act as innovation incubators that help diffuse innovations initially, while majority populations serve as reservoirs that protect against regression to non-adaptive behaviors. We formally show that these effects arise from asymmetric-homophilous social network structure. The results suggest that if cultural and socio-psychological barriers are removed that cause individuals to reject innovations based on group membership, then group structure could promote the diffusion of innovations. Analyzing empirical data or designing new experiments with this model will further advance our understanding of when asymmetric homophily promotes (or possibly inhibits) the diffusion of innovations.