Cultural linkage: the influence of package transmission on cultural dynamics.

Anne Kandler,Laurel Fogarty,D Justin Yeh

doi:10.1098/rspb.2019.1951

Anne Kandler, Laurel Fogarty + Show 1 more

Open Access

https://doi.org/10.1098/rspb.2019.1951

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Abstract

Many cultural traits are not transmitted independently, but together as a package. This can happen because, for example, media may store information together making it more likely to be transmitted together, or through cognitive mechanisms such as causal reasoning. Evolutionary biology suggests that physical linkage of genes (being on the same chromosome) allows neutral and maladaptive genes to spread by hitchhiking on adaptive genes, while the pairwise difference between neutral genes is unaffected. Whether packaging may lead to similar dynamics in cultural evolution is unclear. To understand the effect of cultural packages on cultural evolutionary dynamics, we built an agent-based simulation that allows links to form and break between cultural traits. During transmission, one trait and others that are directly or indirectly connected to it are transmitted together in a package. We compare variation in cultural traits between different rates of link formation and breakage and find that an intermediate frequency of links can lower cultural diversity, which can be misinterpreted as a signature of payoff bias or conformity. Further, cultural hitchhiking can occur when links are common.

Highlights

Defining and quantifying the complexity of a cultural trait is a notoriously difficult task in archaeology and anthropology
The aim of this paper is to understand whether links between cultural traits alter the cultural composition of the population compared to independent trait transmission
We model the evolution of cultural traits under various cultural transmission processes and investigate how the populationlevel signature of such processes, summarized by the level of cultural diversity, changes if we allow links to exist between cultural traits

Summary

Introduction

Defining and quantifying the complexity of a cultural trait is a notoriously difficult task in archaeology and anthropology. The links form randomly at a fixed rate between any two traits in an individual’s cultural repertoire This is consistent with a mechanism of link formation where, for example, a role model demonstrates actions in sequence. Traits may be transmitted together owing to causal reasoning [20], prestige-biased transmission [21] or at the level of trait structure, many complex cultural objects consist of smaller components, perhaps physically linked, which may be transmitted together. The aim of this paper is to understand whether links between cultural traits alter the cultural composition of the population compared to independent trait transmission To this end, we model the evolution of cultural traits under various cultural transmission processes and investigate how the populationlevel signature of such processes, summarized by the level of cultural diversity, changes if we allow links to exist between cultural traits. We discuss the circumstances under which we expect linked cultural transmission to be important—where we need to include a realistic theory of cultural linkage in order to replicate the dynamic of cul- 2 tural change—and the circumstances under which current theory is sufficient

Simulation framework

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