Pathways from education to fertility decline: a multi-site comparative study

Uncertainty in a globalizing world. Livelihood and fertility variance increases in response to rapid change

OBJECTIVES

The extreme condition that we address in this special issue is how people adapt to rapid change, which in this case study is instigated by globalization and the process of market integration. Although market integration has been underway for centuries in some parts of the world, it often occurs precipitously in small-scale societies, initiating an abrupt break with traditional ways of life and fostering a keen sense of uncertainty.

METHODS

Using cross sections from 30-years of data collected in a Yucatec Maya subsistence farming community, we test the expectation that when payoffs to pursue new livelihood and reproductive options are uncertain, variance in social, economic, and reproductive traits will increase in the population. Our data span the transition from subsistence farming to a mixed economy, and bridge the transition from natural to contracepting fertility. Exposure to globalizing and market forces occurred when a paved road was built in the early 2000s.

RESULTS

We find that livelihood traits (a household's primary economic strategy, amount of land under cultivation, amount of maize and honey sold), become more variable as new, but uncertain options become available. Variance in levels of education and family size likewise immediately increase following the road, but show signs of settling back down a decade later. Rather than replacing one way of life with another, Maya farmers conservatively adopt some new elements (family planning, wage labor), until the tradeoffs to commit to smaller families and the labor market become clearer.

CONCLUSION

Our findings highlight that in rapidly changing environments when the payoffs to assimilate new options are uncertain, some households and individuals intensify what they know best, while others adopt new opportunities, driving variance up in the population.

Women's subsistence strategies predict fertility across cultures, but context matters

While it is commonly assumed that farmers have higher, and foragers lower, fertility compared to populations practicing other forms of subsistence, robust supportive evidence is lacking. We tested whether subsistence activities-incorporating market integration-are associated with fertility in 10,250 women from 27 small-scale societies and found considerable variation in fertility. This variation did not align with group-level subsistence typologies. Societies labeled as "farmers" did not have higher fertility than others, while "foragers" did not have lower fertility. However, at the individual level, we found strong evidence that fertility was positively associated with farming and moderate evidence of a negative relationship between foraging and fertility. Markers of market integration were strongly negatively correlated with fertility. Despite strong cross-cultural evidence, these relationships were not consistent in all populations, highlighting the importance of the socioecological context, which likely influences the diverse mechanisms driving the relationship between fertility and subsistence.

From the Ground Up: A Multidisciplinary Approach to Past Fertility and Population Narratives

Population dynamics form a crucial component of human narratives in the past. Population responses and adaptations not only tell us about the human past but also offer insights into the present and future. Though an area of substantial interest, it is also one of often limited evidence. As such, traditional techniques from demography and anthropology must be adapted considerably to accommodate the available archaeological and ethnohistoric data and an appropriate inferential framework must be applied. In this article, I propose a ground-up, multidisciplinary approach to the study of past population dynamics. Specifically, I develop an empirically informed path diagram based on modern fertility interactions and sources of past environmental, sociocultural, and biological evidence to guide high-resolution case studies. The proposed approach is dynamic and can evolve in response to data inputs as case studies are undertaken. In application, this approach will create new knowledge of past population processes which can greatly enhance our presently limited knowledge of high-frequency, small-scale demographic fluctuations, as well as contribute to our broader understanding of significant population disturbances and change throughout human history.

Trends and factors associated with declining lifetime fertility among married women in Kenya between 2003 and 2014: an analysis of Kenya demographic health surveys

BACKGROUND

Globally, fertility has declined in the last three decades. In sub-Saharan Africa Including Kenya, this decline started more recent and at a slower pace compared to other regions. Despite a significant fertility decline in Kenya, there are disparities in intra- and interregional fertility. Reduction in lifetime fertility has health benefits for both the mother and child, thus it is important to improve women and children health outcomes associated with high fertility. The study, therefore evaluated the factors associate with change in lifetime fertility among married women of reproductive age in Kenya between 2003 and 2014.

METHODS

The study used the Kenya Demographic and Health Survey (KDHS) datasets of 2003, 2008 and 2014. Analysis of variance (ANOVA) was used to calculate the mean number of children ever born and to assess the change in fertility across different factors. Poisson regression model with robust standard errors was used to study the relationship between number of children ever born (lifetime fertility) and independent variables. A Poisson-based multivariate decomposition for the nonlinear response model was performed to identify and quantify the contribution of demographic, socioeconomic and reproductive correlates, to the change in lifetime fertility between 2003 and 2014.

RESULTS

The study included 3,917, 4,002, and 7,332 weighted samples of women of reproductive age in 2003, 2008, and 2014, respectively. The mean number of children born declined from 3.8 (95% CI: 3.6-3.9) in 2003 to 3.5 (95% CI: 3.4--3.7) in 2008 and 3.4 (95% CI: 3.3-3.4) in 2014 (p = 0.001). The expected number of children reduced with the age at first sexual intercourse, the age at first marriage across the survey years, and household wealth index. Women who had lost one or more children in the past were likely to have increased number of children. The changes in the effects of women's characteristics between the surveys explained 96.4% of the decline. The main contributors to the change in lifetime fertility was the different in women level of education.

CONCLUSION

The lifetime fertility declined by one-tenth between 2003 and 2014; majorly as a result of the effects of characteristics of women in terms of level of education. These highlights a need to implement education policies that promotes women education focuses on gender equality and women empowerment. Continuous strengthening of the healthcare systems (access to quality antenatal care, skilled delivery, and postpartum care) to reduce child mortality is essential.

The human right to safely give birth: data from 193 countries show that gender equality does affect maternal mortality

BACKGROUND

While a reduction in the global maternal mortality ratio (MMR) has slowed, newer strategies are needed to achieve an ongoing and sustainable reduction of the MMR. Previous studies have investigated the association between health system-related factors such as wealth inequalities, healthcare access and use on maternal mortality. However, a women's rights-based approach to address MMR has not been studied, excluding the health system-related factors. This study aimed to analyse the association between gender equality and MMR globally.

METHODS

Using structural equation modelling (SEM), secondary and open access data from the United Nations and other international agencies from 193 countries were analysed using structural equation modelling (SEM). Gender-sensitive variables that represented the theoretical, conceptual framework of the study were selected. The association between latent variable gender equality and the outcome, MMR, was examined in the SEM. A second SEM model (n = 158) was designed to include two variables related to gender-based violence.

FINDINGS

The latent variable, gender equality, was negatively associated with MMR (p < 0‧001, Z = -6‧96, 95% CI: - 6508.98 to - 3141.89 for Model 1 and p < 0‧001, Z = -7‧23, 95% CI: - 6045.356 to - 3467.515 for Model 2).

INTERPRETATION

Gender equality was significantly associated with maternal mortality. Investing in higher education for women, improving their paid employment opportunities, increasing participation in leadership roles and politics, reducing intimate partner violence (IPV) and ending child marriage can significantly reduce maternal mortality.

Partner's characteristics and adolescent motherhood among married adolescent girls in 48 low-income and middle-income countries: a population-based study

OBJECTIVES

The objective of this study was to examine the prevalence of adolescent motherhood among married adolescent girls and its associations with their partners' characteristics in low-income and middle-income countries (LMICs).

DESIGN

Population-based study.

PARTICIPANTS

54 285 ever married (or lived with a partner) adolescent girls (15-19 years old) were including in prevalence analysis. However, partner characteristics were assessed in a subsample of 24 433 adolescent girls who were married (or living with a partner) at the time of interview.

SETTINGS

Data from the latest available Demographic and Health Survey round during 2010-2018 in 48 LMICs across different geographic regions.

RESULTS

The overall prevalence of adolescent motherhood was 73.98% (95% CI 70.96 to 78.10) among married adolescent girls in this study. In the pooled analysis, statistically significant and positive associations were observed between adolescent motherhood and partners' desire for more children (adjusted marginal effect (AME): 2.34, 95% CI 1.21 to 3.47) and spousal age gap (AME: 1.67, 95% CI 0.30 to 3.04 for three plus age gap). However, no statistically significant association was observed between adolescent motherhood and partners' education (AME: -0.36, 95% CI -1.77 to 1.05 for primary education) and partners' agricultural occupation (AME: 1.07, 95% CI -0.17 to 2.32). Overall, there was significant variation in the associations across countries; however, the positive associations persisted between adolescent motherhood and partners' desire for more children and spousal age gap in most of the studied countries.

CONCLUSIONS

Our findings may inform policymakers about the importance of incorporating partners of married adolescent girls into the existing birth control programmes to delay age at first birth among married adolescents in LMICs. More attention should be given to the married adolescent girls who have older partners, and efforts to discourage marriages with much older partners may have a secondary benefit of reducing adolescent motherhood in LMICs.

Weighted Bayesian Poisson Regression for The Number of Children Ever Born per Woman in Bangladesh

Number of children ever born to women of reproductive age forms a core component of fertility and is vital to the population dynamics in any country. Using Bangladesh Multiple Indicator Cluster Survey 2019 data, we fitted a novel weighted Bayesian Poisson regression model to identify multi-level individual, household, regional and societal factors of the number of children ever born among married women of reproductive age in Bangladesh. We explored the robustness of our results using multiple prior distributions, and presented the Metropolis algorithm for posterior realizations. The method is compared with regular Bayesian Poisson regression model using a Weighted Bayesian Information Criterion. Factors identified emphasize the need to revisit and strengthen the existing fertility-reduction programs and policies in Bangladesh.

Supplementary Information

The online version contains supplementary material available at 10.1007/s44199-022-00044-2.

Theory and explanation in demography: The case of low fertility in Europe

In the 50th anniversary edition of Population Studies, John Hobcraft commented that demographers spend too little time trying to explain the phenomena they measure and describe. A quarter of a century on, this paper looks at the state of theory and explanation in contemporary demography. I ask how demographers have approached the task of explanation since Hobcraft's comment, grounding the discussion in the mainstream literature on low fertility in Europe. Using selected examples, I critically review macro- and micro-level approaches to explanation, highlighting some of the philosophical problems that each encounters. I argue that different conceptions of what demography is, and the explanatory language fertility researchers use, lead to differences in explanatory strategies that are rarely explicitly recognized. I also consider how critical theories challenge demographers to think in new ways. Despite the increasing attention paid to theory and explanation, I conclude that more engagement with the philosophy of social sciences is needed before fertility researchers can legitimately claim their studies do as much to explain and understand as to quantify and describe.

Behavioral Ecology of the Family: Harnessing Theory to Better Understand Variation in Human Families

Researchers across the social sciences have long been interested in families. How people make decisions such as who to marry, when to have a baby, how big or small a family to have, or whether to stay with a partner or stray are questions that continue to interest economists, sociologists, demographers, and anthropologists. Human families vary across the globe; different cultures have different marriage practices, different ideas about who raises children, and even different notions of what a family is. Human behavioral ecology is a branch of anthropology that is particularly interested in cultural variation of family systems and how these differences impact upon the people that inhabit them; the children, parents, grandparents. It draws on evolutionary theory to direct research and generate testable hypotheses to uncover how different ecologies, including social contexts, can explain diversity in families. In this Special Issue on the behavioral ecology of the family, we have collated a selection of papers that showcase just how useful this framework is for understanding cultural variation in families, which we hope will convince other social scientists interested in family research to draw upon evolutionary and ecological insight in their own work.

Effects of family planning on fertility behaviour across the demographic transition

The adoption of contraception often coincides with market integration and has transformative effects on fertility behavior. Yet many parents in small-scale societies make decisions about whether and when to adopt family planning in an environment where the payoffs to  have smaller families are uncertain. Here we track the fertility of Maya women across 90 years, spanning the transition from natural to contracepting fertility. We first situate the uncertainty in which fertility decisions are made and model how childbearing behaviors respond. We find that contraception, a key factor in cultural transmission models of fertility decline, initially has little effect on family size as women appear to hedge their bets and adopt fertility control only at the end of their reproductive careers. Family planning is, however, associated with the spread of lower fertility in later cohorts. Distinguishing influences on the origin versus spread of a behaviour provides valuable insight into causal factors shaping individual and normative changes in fertility.

Conjoint analysis to understand preferences of contraceptives among women of reproductive age in Ukraine

This article describes the results of marketing research using conjoint analysis that was conducted to establish the preferences of contraceptives among women of reproductive age in Ukraine to further use the results for effective marketing decisions making in the pharmaceutical industry.

It was established that the women`s choice differs significantly depending on their main socioeconomic characteristics: age, income level, and level of education. Priority contraceptives from hormonal, non-hormonal contraceptives, as well as contraceptive medical devices for different age groups of women, was identified. Alfred Marshall’s main economic law was confirmed and the existence of price elasticity according to preferences was established.

The results obtained on women’s preferences for certain types of contraceptives will improve the level of compliance, women’s pharmaceutical safety and promote a balance between women’s needs and the capabilities of the contraception supply system.

Disentangling wealth effects on fertility in 64 low- and middle-income countries

Studies have shown mixed associations between wealth and fertility, a finding that has posed ongoing puzzles for evolutionary theories of human reproduction. However, measures of wealth do not simply capture economic capacity, which is expected to increase fertility. They can also serve as a proxy for market opportunities available to a household, which may reduce fertility. The multifaceted meaning of many wealth measures obscures our ability to draw inferences about the relationship between wealth and fertility. Here, we disentangle economic capacity and market opportunities using wealth measures that do not carry the same market-oriented biases as commonly used asset-based measures. Using measures of agricultural and market-based wealth for 562,324 women across 111,724 sampling clusters from 151 DHS surveys in 64 countries, we employ a latent variable structural equation model to estimate (a) latent variables capturing economic capacity and market opportunity and (b) their effects on completed fertility. Market opportunities had a consistent negative effect on fertility, while economic capacity had a weaker but generally positive effect on fertility. The results show that the confusion between operational measures of wealth and the concepts of economic capacity can impede our understanding of how material resources and market contexts shape reproduction.

Determinants of Change in Fertility among Women in Rural Areas of Uganda

Fertility among rural women in Uganda continues to decline. Studies on fertility in Uganda have focused on the overall fertility in the country. In this study, we focus on determinants of change in fertility among rural women in Uganda using a multivariate Poisson decomposition technique to quantify the contribution of changes in the socioeconomic and demographic composition of women which we also refer to as the characteristic effects and changes in their fertility behavior (the coefficients' effects or risk of childbearing) to the overall reduction in fertility among women in rural areas during the 2006–2016 period. The “characteristics effects” are used to mean the effect of changing composition of women by the socioeconomic and demographic characteristics between 2006 and 2016. On the other hand, fertility behavior also presented as coefficients' effects mean changes in the risk or likelihood of giving birth to children by the rural women between the two survey years. Our findings indicate that the mean number of children ever born (MCEB) reduced from 4.5 to 3.9 in 2006 and this reduction was associated with both the changes in composition of women and fertility behavior. The composition of women contributed to 42% while the fertility behavior contributed to 58% of the observed reduction. The education level attained and the age at first sex showed significant contributions on both components of the decomposition. The observed decline in fertility is largely associated with the variation in the risk of childbearing among the rural women. The variation in the risk of childbearing by education and age at first sex of the rural women showed to be the biggest contribution to the observed change in fertility. Continued improvements in access, attendance, and completion of secondary schools by women in rural areas will be the key drivers to Uganda's overall transition to low fertility. Furthermore, with improved access to mass media in the rural areas, there can be changes in attitudes and large family size preferences which can create a conducive environment for the utilization of family planning services in the rural communities. Efforts should therefore focus on applying appropriate methods to deliver packaged family planning messages to these communities.

The health benefits of secondary education in adolescents and young adults: An international analysis in 186 low-, middle- and high-income countries from 1990 to 2013

Background

The health benefits of secondary education have been little studied. We undertook country-level longitudinal analyses of the impact of lengthening secondary education on health outcomes amongst 15-24 year olds.

Methods

Exposures: average length of secondary and primary education from 1980 to 2013.

Data/Outcomes: Country level adolescent fertility rate (AFR), HIV prevalence and mortality rate from 1989/90 to 2013 across 186 low-, middle- and high-income countries.

Analysis: Longitudinal mixed effects models, entering secondary and primary education together, adjusted for time varying GDP and country income status. Longitudinal structural marginal models using inverse probability weighting (IPW) to take account of time varying confounding by primary education and GDP. Counterfactual scenarios of no change in secondary education since 1980/1990 were estimated from model coefficients for each outcome.

Findings

Each additional year of secondary education decreased AFR by 8.4% in mixed effects models and 14.6% in IPW models independent of primary education and GDP. Counterfactual analyses showed the proportion of the reduction in adolescent fertility rate over the study period independently attributable to secondary education was 28% in low income countries. Each additional year of secondary education reduced mortality by 16.9% for 15-19 year and 14.8% for 20-24 year old young women and 11.4% for 15-19 year and 8.8% for 20-24 year old young men. Counterfactual scenarios suggested 12% and 23% of the mortality reduction for 15-19 and 20-24 year old young men was attributable to secondary education in low income countries. Each additional year of secondary education was associated with a 24.5% and 43.1% reduction in HIV prevalence amongst young men and women.

Interpretation

The health benefits associated with secondary education were greater than those of primary education and were greatest amongst young women and those from low income countries. Secondary education has the potential to be a social vaccine across many outcomes in low and middle income countries.

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Greater primary education is associated with health benefits.

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Studies suggest that education may have causal effects on health.

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The health benefits of secondary education are greater than for primary education.

The ex-pat effect: presence of recent Western immigrants is associated with changes in age at first birth and birth rate in a Maya population from rural Guatemala

BACKGROUND

Economic transitions expose indigenous populations to a variety of ecological and cultural challenges, especially regarding diet and stress. These kinds of challenges are predicted by evolutionary ecological theory to have fitness consequences (differential reproduction) and, indeed, are often associated with changes in fertility dynamics. It is currently unclear whether international immigration might impact the nature of such an economic transition or its consequences for fertility.

AIM

To examine measures of fertility, diet and stress in two economically transitioning Maya villages in Guatemala that have been differentially exposed to immigration by Westerners.

SUBJECTS AND METHODS

This study compared Maya women's ages at first birth and birth rates between villages and investigated whether these fertility indicators changed through time. It also explored whether the villages differed in relation to diet and/or a proxy of stress.

RESULTS

It was found that, in the village directly impacted by immigration, first births occurred earlier, but birth rate was slower. In both villages, over the sampled time window, age at first birth increased, while birth rate decreased. The villages do not differ significantly in dietary indicators, but the immigration-affected village scored higher on the stress proxy.

CONCLUSION

Immigration can affect fertility in host communities. This relationship between immigration and fertility dynamics may be partly attributable to stress, but this possibility should be evaluated prospectively in future research.

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

Several empirical observations suggest that when women have more autonomy over their reproductive decisions, fertility is lower. Some evolutionary theorists have interpreted this as evidence for sexual conflicts of interest, arguing that higher fertility is more adaptive for men than women. We suggest the assumptions underlying these arguments are problematic: assuming that women suffer higher costs of reproduction than men neglects the (different) costs of reproduction for men; the assumption that men can repartner is often false. We use simple models to illustrate that (i) menorwomen can prefer longer interbirth intervals (IBIs), (ii) if men can only partner with wives sequentially they may favour shorter IBIs than women, but such a strategy would only be optimal for a few men who can repartner. This suggests that an evolved universal male preference for higher fertility than women prefer is implausible and is unlikely to fully account for the empirical data. This further implies that if women have more reproductive autonomy, populations should grow, not decline. More precise theoretical explanations with clearly stated assumptions, and data that better address both ultimate fitness consequences and proximate psychological motivations, are needed to understand under which conditions sexual conflict over reproductive timing should arise.

Status competition, inequality, and fertility: implications for the demographic transition

The role that social status plays in small-scale societies suggests that status may be important for understanding the evolution of human fertility decisions, and for understanding how such decisions play out in modern contexts. This paper explores whether modelling competition for status--in the sense of relative rank within a society--can help shed light on fertility decline and the demographic transition. We develop a model of how levels of inequality and status competition affect optimal investment by parents in the embodied capital (health, strength, and skills) and social status of offspring, focusing on feedbacks between individual decisions and socio-ecological conditions. We find that conditions similar to those in demographic transition societies yield increased investment in both embodied capital and social status, generating substantial decreases in fertility, particularly under conditions of high inequality and intense status competition. We suggest that a complete explanation for both fertility variation in small-scale societies and modern fertility decline will take into account the effects of status competition and inequality.

The cultural evolution of fertility decline

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.

Understanding variation in human fertility: what can we learn from evolutionary demography?

Decades of research on human fertility has presented a clear picture of how fertility varies, including its dramatic decline over the last two centuries in most parts of the world. Why fertility varies, both between and within populations, is not nearly so well understood. Fertility is a complex phenomenon, partly physiologically and partly behaviourally determined, thus an interdisciplinary approach is required to understand it. Evolutionary demographers have focused on human fertility since the 1980s. The first wave of evolutionary demographic research made major theoretical and empirical advances, investigating variation in fertility primarily in terms of fitness maximization. Research focused particularly on variation within high-fertility populations and small-scale subsistence societies and also yielded a number of hypotheses for why fitness maximization seems to break down as fertility declines during the demographic transition. A second wave of evolutionary demography research on fertility is now underway, paying much more attention to the cultural and psychological mechanisms underpinning fertility. It is also engaging with the complex, multi-causal nature of fertility variation, and with understanding fertility in complex modern and transitioning societies. Here, we summarize the history of evolutionary demographic work on human fertility, describe the current state of the field, and suggest future directions.