The cultural evolution of fertility decline

Abstract

Cultural evolutionists have long been interested in the problem of why fertility declines as populations develop. By outlining plausible mechanistic links between individual decision-making, information flow in populations and competition between groups, models of cultural evolution offer a novel and powerful approach for integrating multiple levels of explanation of fertility transitions. However, only a modest number of models have been published. Their assumptions often differ from those in other evolutionary approaches to social behaviour, but their empirical predictions are often similar. Here I offer the first overview of cultural evolutionary research on demographic transition, critically compare it with approaches taken by other evolutionary researchers, identify gaps and overlaps, and highlight parallel debates in demography. I suggest that researchers divide their labour between three distinct phases of fertility decline—the origin, spread and maintenance of low fertility—each of which may be driven by different causal processes, at different scales, requiring different theoretical and empirical tools. A comparative, multi-level and mechanistic framework is essential for elucidating both the evolved aspects of our psychology that govern reproductive decision-making, and the social, ecological and cultural contingencies that precipitate and sustain fertility decline.

Childhood environmental harshness predicts coordinated health and reproductive strategies: A cross-sectional study of a nationally representative sample from France

“…In our representative sample of a country where the demographic transition has long been completed, mean fertility is indeed close to two children per parent with little variation around this value. Cultural factors such as easy access to contraceptives, universal health care for both the child and the parents, widespread access to wage labor via economic markets for women and highly shared norms about family size might for example explain why fertility is disconnected from the fast-slow continuum (Colleran, 2016;Lawson & Borgerhoff Mulder, 2016). Eventually, several meaningful axes of variation are likely to emerge once one tries to capture finer inter-individual differences in life strategies across human populations and to identify particular socioecological factors that call for more diverse clusters of allocation strategies (Del Giudice, 2014b).…”

Cultural evolutionary theory: How culture evolves and why it matters

“…Further, aspects of cultural transmission, such as prestige bias and the choice of nonparental cultural role models, can facilitate the spread of fertility-reducing behaviors (12,153). Thus, cultural evolutionary approaches should be integrated into demography, especially the processes that have led to fertility decline (154).…”

What if fertility decline is not permanent? The need for an evolutionarily informed approach to understanding low fertility

“…There is an entire field of study devoted to cultural evolution, and fertility decline is a commonly addressed topic [29,30]. We especially disagree with the notion that contraception breaks the link between human fertility and the processes of evolution.…”

“…Regardless of the degree of genetic influence, even decisions that are strongly influenced by socially transmitted norms are useful to study from an evolutionary point of view [29,34]. The mind, culture and consciousness are also products of evolution.…”