Supplementary material from "Evolutionary dynamics of sustainability ideas in China: inferences from ecological and economic concepts usage in People's Daily"

Previous cultural evolutionary analyses have exploited the use of neutral models, or random copying models, analogous to neutral genetic drift, as null models to distinguish the unbiased copying and biased transmission of neutral cultural traits, but the dynamics and underlying mechanism of non-neutral cultural traits have not yet been explored. Adopting an ecological perspective, we define ecological and economic concepts as non-neutral cultural traits constitute a complex ecosystem of meaning representing sustainability ideas. We analyse the frequency distribution, turnover and innovation rates of nearly 4000 concepts appearing in People's Daily from 1946 to 2015. The results reveal that, ecological concepts show stronger tendency towards random copying than economic concepts. The popular ecological and economic concepts may experience conformist bias and anti-conformist bias respectively. Semantic and pragmatic differences of popular concepts affect the variability which indicate stronger cultural drift in the ontological domain. The frequency change in popular concepts also suggests positive selection due to political strategy and governmental policy.