Layered social influence promotes multiculturality in the Axelrod model

TL;DR

This paper demonstrates that layered social influence mechanisms naturally promote and sustain multiculturality in social systems, even with few cultural traits and despite cultural drift, by analyzing both synthetic and real-world networks.

Contribution

It introduces a layered social influence model that explains the robustness of multiculturality and coexistence of different consensus levels, extending Axelrod's model to more realistic social structures.

Findings

Multicultural regimes are stable with low cultural traits due to layered influence.

Layered influence increases robustness against cultural drift.

Real-world networks exhibit persistent multiculturality with few traits.

Abstract

Why is our society multicultural? Based on the two mechanisms of homophily and social influence, the classical model for the dissemination of cultures proposed by Axelrod predicts the existence of a fragmented regime where different cultures can coexist in a social network. However, in such model the multicultural regime is achievable only when a high number of cultural traits is present, and is not robust against cultural drift, i.e. the spontaneous mutations of agents' traits. In real systems, social influence is inherently organised in layers, meaning that individuals tend to diversify their connections according to the topic on which they interact. In this work we show that the observed persistence of multiculturality in real-world social systems is a natural consequence of the layered organisation of social influence. We find that the critical number of cultural traits that separates the monocultural and the multicultural regimes depends on the redundancy of pairwise connections across layers. Surprisingly, for low values of structural redundancy the system is always in a multicultural state, independently on the number of traits, and is robust to the presence of cultural drift. Moreover, we show that layered social influence allows the coexistence of different levels of consensus on different topics. The insight obtained from simulations on synthetic graphs are confirmed by the analysis of two real-world social networks, where the multicultural regime persists even for a very small number of cultural traits, suggesting that the layered organisation of social interactions might indeed be at the heart of multicultural societies.