Cultural evolution and prehistoric demography

Abstract

One prominent feature of human culture is that different populations have different tools, technologies and cultural artefacts, and these unique toolkits can also differ in size and complexity. Over the past few decades, researchers in the fields of prehistoric demography and cultural evolution have addressed a number of questions regarding variation in toolkit size and complexity across prehistoric and modern populations. Several factors have been proposed as possible explanations for this variation: in particular, the mobility of a population, the resources it uses, the volatility of its environment and the number of individuals in the population. Using a variety of methods, including empirical and ethnographic research, computational models and laboratory-based experiments, researchers have found disparate results regarding each hypothesis. These discordant findings have led to debate over the factors that most significantly influence toolkit size and composition. For instance, several computational, empirical and laboratory studies of food-producing populations have found a positive correlation between the number of individuals in a population and toolkit size, whereas similar studies of hunter-gatherer populations have found little evidence of such a link. In this paper, we conduct a comprehensive review of the literature in this field of study and propose corollaries and interdisciplinary approaches with the goal of reconciling dissimilar findings into a more comprehensive view of cultural toolkit variation. This article is part of the theme issue 'Cross-disciplinary approaches to prehistoric demography'.

Keywords: cultural evolution; cultural repertoire; population size; prehistoric demography; toolkit complexity.

Figure 1.

Schematic illustrating the potential effects of levels of connectivity between populations of different sizes on each population's toolkit size. Shade represents toolkit size (a darker shade means a larger toolkit, while a lighter shade means a smaller toolkit), and circle size corresponds to population size (N). Row (a) represents no connectivity; hence, each population is isolated. Row (b) represents low levels of migration between groups, indicated by thin lines between each population, and row (c) represents high levels of migration between groups, indicated by thick lines between each population. Here, we assume a positive link between population size and toolkit size. Migration/connectivity level represents the degree to which populations interact and exchange tools. Importantly, we illustrate that under these conditions, connection to larger populations can greatly increase the toolkit size of smaller populations, whereas a larger population connected to smaller populations might not reap the same benefits from connectivity.

Figure 2.

Conceptualizing types of specialization within a larger population. (a) Illustration of a system where the entire population is generalist and has the same homogeneous toolkit. (b) This figure shows a system structurally similar to many historical and modern food-producing societies, where a group of generalists shares its entire toolkit with many smaller guilds or apprenticeships (which could specialize in tasks such as hunting, farming, or producing goods). Each specialized guild/subgroup has its own unique toolkit in addition to the generalist toolkit that the entire population knows. (c) Depiction of a system of division of labour by sex that mimics the structure of many hunter–gatherer groups and incorporates a small elder subpopulation. All three of these specialized subpopulations are connected by the generalist toolkit that everyone in the population knows.