Community-level education accelerates the cultural evolution of fertility decline

Abstract

Explaining why fertility declines as populations modernize is a profound theoretical challenge. It remains unclear whether the fundamental drivers are economic or cultural in nature. Cultural evolutionary theory suggests that community-level characteristics, for example average education, can alter how low-fertility preferences are transmitted and adopted. These assumptions have not been empirically tested. Here, we show that community-level education accelerates fertility decline in a way that is neither predicted by individual characteristics, nor by the level of economic modernization in a population. In 22 high-fertility communities in Poland, fertility converged on a smaller family size as average education in the community increased—indeed community-level education had a larger impact on fertility decline than did individual education. This convergence was not driven by educational levels being more homogeneous, but by less educated women having fewer children than expected, and more highly educated social networks, when living among more highly educated neighbours. The average level of education in a community may influence the social partners women interact with, both within and beyond their immediate social environments, altering the reproductive norms they are exposed to. Given a critical mass of highly educated women, less educated neighbours may adopt their reproductive behaviour, accelerating the pace of demographic transition. Individual characteristics alone cannot capture these dynamics and studies relying solely on them may systematically underestimate the importance of cultural transmission in driving fertility declines. Our results are inconsistent with a purely individualistic, rational-actor model of fertility decline and suggest that optimization of reproduction is partly driven by cultural dynamics beyond the individual.

What do men want? Re-examining whether men benefit from higher fertility than is optimal for women

“…There are many other proposed pathways whereby improving the social capital of women can motivate lower fertility (e.g. changing sources of social information or the status benefits to other behaviour) [36,37,83]. These explanations do not rely on a commitment to the fertility reduction itself reflecting a fitness-maximizing strategy.…”

“…This has led some researchers to suggest that the nineteenth to twentieth century demographic transitions reflect female preferences for lower fertility [3,4], and furthermore that these preferences may reflect females' adaptive reproductive strategies for smaller family sizes [20,32 -35]. This is a nascent field of inquiry among evolutionists and the arguments are not yet well fleshed-out, but the empirical association between female education and lower fertility is well documented at both the individual and group levels [36][37][38][39].…”

Evaluating reproductive decisions as discrete choices under social influence

“…Transparent social influence might come from an acknowledged village expert in a particular category [31], whereas less-intense influence might diffuse among passive members of village social networks, who might not necessarily adopt the behaviour themselves [32]. Among over 20 high-fertility communities in rural Poland, for example, Colleran et al [16] found that the low-fertility norms of educated women were learned socially by lesser educated women within the same social networks who were using the more-educated women as models.…”

“…[14]) those variables are seen as insufficient to change behaviour without the addition of social influence [15]. For example, in Poland, poor uneducated women living in a wealthy educated group tend to adopt the low-fertility level of the group rather than the higher fertility that otherwise would be associated with their low income and low education as individuals [16].…”

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

“…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.…”