Heterogeneous individuals impede the establishment of cultures in animal groups

Andrew Allan, Simon Kenworthy, Guy Cowlishaw, Alecia Carter

Social learning facilitates the diffusion of novel behaviours (i.e., inventions) through groups and is a key component in the development of culture. The speed with which an invention spreads through a group is largely determined by the strength of social connections and network structure; however, research concerning the establishment of inventions (i.e., culture) has typically overlooked that individuals differ in their propensities for social learning. The aim of this study was to assess how the presence and extent of heterogeneity in propensity for social learning can interact with transmission probability (i.e., the complexity and regularity of the task being performed), network size and structure, and attribute distributions (i.e., homophilic or random) to regulate the likelihood of establishing inventions. We found that the extent of information diffusion was lower in heterogeneous than homogeneous populations, but only when transmission probability was at intermediate levels – full adoption of an invention in a group was consistently observed when transmission probability was high (e.g., simple, regularly occurring tasks) but was rare when transmission probability was low (e.g., complex and rarely occurring tasks). When heterogeneity was held high, homophilic distributions had an additional negative effect on the extent of information diffusion, but again, only when transmission probability was at intermediate levels. Given the variety of intraspecies phenotypic diversity identified in wild animals, our results highlight the importance of including heterogeneity and homophily when investigating culture. Researchers can use our model to make predictions about the conditions that may facilitate animal culture in a wide range of taxa.