title: Population size vs. social connectedness - A gene-culture coevolutionary approach to cumulative cultural evolution.
abstract: It has long been debated if population size is a crucial determinant of the level of culture. While empirical results are mixed, recent theoretical studies suggest that social connectedness between people may be a more important factor than the size of the entire population. These models, however, do not take into account evolutionary responses of learning strategies determining the mode of transmission and innovation and are hence not suitable for predicting the long-term implications of parameters of interest. In the present paper, to address this issue, we provide a gene-culture coevolution model, in which the microscopic learning process of each individual is explicitly described as a continuous-time stochastic process and time allocation to social and individual learning is allowed to evolve. We have found that social connectedness has a larger impact on the equilibrium level of culture than population size especially when connectedness is weak and population size is large. This result, combined with those of previous culture-only models, points to the importance of studying separate effects of population size and internal social structure to better understand spatiotemporal variation in the level of culture.
authors.affiliation: Research Center for Future Design, Kochi University of Technology, Kochi 780-8515, Japan; School of Economics and Management, Kochi University of Technology, Kochi 780-8515, Japan. Electronic address: kobayashi.yutaka@kochi-tech.ac.jp.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: SOKENDAI (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Ohtsuki
authors.affiliation: Meiji Institute for Advanced Study of Mathematical Sciences, Nakano, Tokyo 164-8525, Japan.
authors.forename: Joe Y
authors.initials: JY
authors.lastname: Wakano
mesh_terms: D005075:Biological Evolution; D003468:Cultural Evolution; D006801:Humans; D007858:Learning; D008962:Models, Theoretical; D011156:Population Density
keywords: Demography; Dual inheritance theory; Skill; Success-biased transmission; Technology