Fertility decline and the changing dynamics of wealth,status and inequality

In the course of demographic transitions (DTs), two large-scale trends become apparent: (i) the broadly positive association between wealth, status and fertility tends to reverse, and (ii) wealth inequalities increase and then temporarily decrease. We argue that these two broad patterns are linked, through a diversification of reproductive strategies that subsequently converge as populations consume more, become less self-sufficient and increasingly depend on education as a route to socio-economic status. We examine these links using data from 22 mid-transition communities in rural Poland. We identify changing relationships between fertility and multiple measures of wealth, status and inequality. Wealth and status generally have opposing effects on fertility, but these associations vary by community. Where farming remains a viable livelihood, reproductive strategies typical of both pre- and post-DT populations coexist. Fertility is lower and less variable in communities with lower wealth inequality, and macro-level patterns in inequality are generally reproduced at the community level. Our results provide a detailed insight into the changing dynamics of wealth, status and inequality that accompany DTs at the community level where peoples'' social and economic interactions typically take place. We find no evidence to suggest that women with the most educational capital gain wealth advantages from reducing fertility, nor that higher educational capital delays the onset of childbearing in this population. Rather, these patterns reflect changing reproductive preferences during a period of profound economic and social change, with implications for our understanding of reproductive and socio-economic inequalities in transitioning populations.     

Do Markets Worsen Economic Inequalities? Kuznets in the Bush

Integration into a market economy or economic development can erode the quality of life of indigenous people by, for example, increasing income inequalities. The Kuznets hypothesis predicts that the link between income inequality and income (a proxy for economic development) resembles an inverted U. We test the hypothesis using a survey of 511 households from 59 villages of Tsimane' Amerindians, a horticultural-foraging society in the tropical rain forest of Bolivia. We measure village inequalities of three economic outcomes: income, imputed annual value of rice production, and wealth. We used three indices of inequality: the coefficient of variation, the standard deviation of the logarithm, and the Gini coefficient. Explanatory variables include either income and income squared, wealth and wealth squared, or imputed annual rice production and production squared. We used village-to-town distance as a control. We find little evidence that integration to the market increases inequalities of economic outcomes, with two exceptions: Wealth bore the predicted inverted U-shaped relation with wealth inequalities, and imputed rice production bore a U-shaped relation to inequality, but only when (a) using adult equivalents to express household size and (b) the Gini coefficient and the coefficient of variation to measure inequality; in no case were results robust to different econometric specifications. We advance several explanations for why economic development might not accentuate economic inequalities among relatively autarkic rural economies.     

The Link between Inequality and Population Health in Low and Middle Income Countries: Policy Myth or Social Reality?

An influential policy idea states that reducing inequality is beneficial for improving health in the low and middle income countries (LMICs). Our study provides an empirical test of this idea: we utilized data collected by the Demographic and Health Surveys between 2000 and 2011 in as much as 52 LMICs, and we examined the relationship between household wealth inequality and two health outcomes: anemia status (of the children and their mothers) and the women'' experience of child mortality. Based on multi-level analyses, we found that higher levels of household wealth inequality related to worse health, but this effect was strongly reduced when we took into account the level of individuals'' wealth. However, even after accounting for the differences between individuals in terms of household wealth and other characteristics, in those LMICs with higher household wealth inequality more women experienced child mortality and more children were tested with anemia. This effect was partially mediated by the country''s level and coverage of the health services and infrastructure. Furthermore, we found higher inequality to be related to a larger health gap between the poor and the rich in only one of the three examined samples. We conclude that an effective way to improve the health in the LMICs is to increase the wealth among the poor, which in turn also would lead to lower overall inequality and potential investments in public health infrastructure and services.     

Rich-poor gap in utilization of reproductive and child health services in India, 1992-2005

This paper examines the trends in utilization of five indicators of reproductive and child health services, namely, childhood immunization, medical assistance at delivery, antenatal care, contraceptive use and unmet need for contraception, by wealth index of the household in India and two disparate states, Uttar Pradesh and Maharashtra. The data from three rounds of the National Family and Health Survey conducted during 1992-2005 are analysed. The wealth index is computed using principal component derived weights from a set of consumer durables, land size, housing quality and water and sanitation facilities of the household, and classified into quintiles for all three rounds. Bivariate analyses, rich-poor ratio and concentration index are used to understand the trends in utilization of, and inequality in, reproductive and child health services. The results indicate huge disparities in utilization of these services, largely to the disadvantage of the poor. Utilization of basic childhood immunization among the poorest and the poor stagnated in India, as well as in both states, during 1998-2005 compared with 1992-1998. The use of maternal care services such as medical assistance at delivery and antenatal care remained at a low level among the poor over this period. However, contraceptive use increased relatively faster among the poor, even with higher unmet need. Of all these services, the inequality in medical assistance at delivery is consistently large, while that of contraceptive use is small. The state-level differences in service coverage by wealth quintiles over time are large.     

The evolution of inequality

Understanding how systems of political and economic inequality evolved from relatively egalitarian origins has long been a focus of anthropological inquiry. Many hypotheses have been suggested to link socio‐ecological features with the rise and spread of inequality, and empirical tests of these hypotheses in prehistoric and extant societies are increasing. In this review, we synthesize several streams of theory relevant to understanding the evolutionary origins, spread, and adaptive significance of inequality. We argue that while inequality may be produced by a variety of localized processes, its evolution is fundamentally dependent on the economic defensibility and transmissibility of wealth. Furthermore, these properties of wealth could become persistent drivers of inequality only following a shift to a more stable climate in the Holocene. We conclude by noting several key areas for future empirical research, emphasizing the need for more analyses of contemporary shifts toward institutionalized inequality as well as prehistoric cases.     

Relative Deprivation and Relative Wealth Enhances Anti-Immigrant Sentiments: The V-Curve Re-Examined

Previous research has shown that negative attitudes towards immigrants and support for anti-immigrant parties are observed both among those experiencing relative deprivation and those experiencing relative gratification (so called v-curve). Whereas the effect of relative deprivation is intuitive, the effect of relative gratification is more difficult to explain. Why would economic prosperity provoke negative attitudes towards immigrants? We first present correlational (Study 1) and experimental (Study 2) support for the v-curve. In Study 1, in a national Swiss referendum, a higher percentage anti-immigrant voting was found in cantons with relatively lower and relatively higher relative disposable income. In Study 2, in a hypothetical society, more opposition to ‘newcomers’ joining society was found among poor or above average wealth group members than among those in a moderate wealth group condition. In Study 3, we replicate this finding and also show that opposition to immigration is higher for all wealth groups when societal inequality is growing rather than declining. In a final study, we examine different forms of relative gratification and mediators of the relationship between relative gratification and opposition to immigration (i.e., identification, collective self-definition as competent and cold, and fear about future wealth). Only fear about future wealth mediates this relationship. We conclude that, paradoxically, relative gratification effects are partly due to the fear of future deprivation.     

Child health inequality in Sub-Saharan Africa

We investigate child height inequality and inequality of predicted height in the Sub-Saharan Africa (SSA) region by socioeconomic, demographic and geographical factors. We characterize their changes in age-cohorts (from 0‐1 up to 4‐5 years old) and determine the contribution of each factor to these changes. We extract data from the Demographic and Health Surveys (DHS) for 33 SSA countries covering the period from 2009 to 2016. Our measure of health is the standardized height of children below the age of five, adjusted by the age and gender distribution in each country. We show that height inequality is lower for older children than for their younger peers. However, the share of inequality caused by our set of factors rises along the age distribution in more than 80% of countries. We find that family background (reflected by maternal education and the household wealth), followed by home infrastructures related to water, toilet and cooking facilities, and the region of residence contribute to explaining the differences observed in child health inequality along the age distribution in SSA.     

Socio-economic determinants of health and physical fitness in southern Ethiopia

The dependence of health and physical fitness on the socio-economic factors of rural families in southern Ethiopia is investigated, with particular emphasis on the role of inequality. This paper contributes to our knowledge of the effect of inequality on health in several ways: it compares the results of objective and subjective health measures, it distinguishes between wealth inequality and nutrition inequality, and it evaluates the impact of nutrition inequality both at the village level and at the household level. The subjective health measures are the number of days respondents were ill during the last month, their ability to walk distances, their ability to carry heavy loads, and their ability to work in the field. The objective health measure is having Body Mass Index (BMI) lower than 18.5. Males are healthier than females. Height has a positive and significant effect on health and fitness and the same is true for per-capita wealth measured at the village level. Availability of satisfactory health facilities has a negative effect on morbidity. Per-capita wealth inequality is positively associated with morbidity and with a low BMI. Within-household nutrition inequality has a complex effect on health and physical fitness: the effect is negative, but only for household members whose nutritional status is above the household mean. The results indicate a clear positive effect of economic well-being on health and physical fitness. The role of inequality is less clear, and certainly deserves further analyses at both the theoretical and empirical levels.     

Craniometric data support a mosaic model of demic and cultural Neolithic diffusion to outlying regions of Europe

The extent to which the transition to agriculture in Europe was the result of biological (demic) diffusion from the Near East or the adoption of farming practices by indigenous hunter-gatherers is subject to continuing debate. Thus far, archaeological study and the analysis of modern and ancient European DNA have yielded inconclusive results regarding these hypotheses. Here we test these ideas using an extensive craniometric dataset representing 30 hunter-gatherer and farming populations. Pairwise population craniometric distance was compared with temporally controlled geographical models representing evolutionary hypotheses of biological and cultural transmission. The results show that, following the physical dispersal of Near Eastern/Anatolian farmers into central Europe, two biological lineages were established with limited gene flow between them. Farming communities spread across Europe, while hunter-gatherer communities located in outlying geographical regions adopted some cultural elements from the farmers. Therefore, the transition to farming in Europe did not involve the complete replacement of indigenous hunter-gatherer populations despite significant gene flow from the Southwest Asia. This study suggests that a mosaic process of dispersal of farmers and their ideas was operating in outlying regions of Europe, thereby reconciling previously conflicting results obtained from genetic and archaeological studies.     

Attention to Local Health Burden and the Global Disparity of Health Research

Most studies on global health inequality consider unequal health care and socio-economic conditions but neglect inequality in the production of health knowledge relevant to addressing disease burden. We demonstrate this inequality and identify likely causes. Using disability-adjusted life years (DALYs) for 111 prominent medical conditions, assessed globally and nationally by the World Health Organization, we linked DALYs with MEDLINE articles for each condition to assess the influence of DALY-based global disease burden, compared to the global market for treatment, on the production of relevant MEDLINE articles, systematic reviews, clinical trials and research using animal models vs. humans. We then explored how DALYs, wealth, and the production of research within countries correlate with this global pattern. We show that global DALYs for each condition had a small, significant negative relationship with the production of each type of MEDLINE articles for that condition. Local processes of health research appear to be behind this. Clinical trials and animal studies but not systematic reviews produced within countries were strongly guided by local DALYs. More and less developed countries had very different disease profiles and rich countries publish much more than poor countries. Accordingly, conditions common to developed countries garnered more clinical research than those common to less developed countries. Many of the health needs in less developed countries do not attract attention among developed country researchers who produce the vast majority of global health knowledge—including clinical trials—in response to their own local needs. This raises concern about the amount of knowledge relevant to poor populations deficient in their own research infrastructure. We recommend measures to address this critical dimension of global health inequality.     

Social learning among Congo Basin hunter-gatherers

This paper explores childhood social learning among Aka and Bofi hunter-gatherers in Central Africa. Existing literature suggests that hunter-gatherer social learning is primarily vertical (parent-to-child) and that teaching is rare. We use behavioural observations, open-ended and semi-structured interviews, and informal and anecdotal observations to examine the modes (e.g. vertical versus horizontal/oblique) and processes (e.g. teaching versus observation and imitation) of cultural transmission. Cultural and demographic contexts of social learning associated with the modes and processes of cultural transmission are described. Hunter-gatherer social learning occurred early, was relatively rapid, primarily vertical under age 5 and oblique and horizontal between the ages of 6 and 12. Pedagogy and other forms of teaching existed as early as 12 months of age, but were relatively infrequent by comparison to other processes of social learning such as observation and imitation.     

Foraging and farming as niche construction: stable and unstable adaptations

All forager (or hunter-gatherer) societies construct niches, many of them actively by the concentration of wild plants into useful stands, small-scale cultivation, burning of natural vegetation to encourage useful species, and various forms of hunting, collectively termed 'low-level food production'. Many such niches are stable and can continue indefinitely, because forager populations are usually stable. Some are unstable, but these usually transform into other foraging niches, not geographically expansive farming niches. The Epipalaeolithic (final hunter-gatherer) niche in the Near East was complex but stable, with a relatively high population density, until destabilized by an abrupt climatic change. The niche was unintentionally transformed into an agricultural one, due to chance genetic and behavioural attributes of some wild plant and animal species. The agricultural niche could be exported with modifications over much of the Old World. This was driven by massive population increase and had huge impacts on local people, animals and plants wherever the farming niche was carried. Farming niches in some areas may temporarily come close to stability, but the history of the last 11,000 years does not suggest that agriculture is an effective strategy for achieving demographic and political stability in the world's farming populations.     

Income inequality and depression: a systematic review and meta‐analysis of the association and a scoping review of mechanisms

Most countries have witnessed a dramatic increase of income inequality in the past three decades. This paper addresses the question of whether income inequality is associated with the population prevalence of depression and, if so, the potential mechanisms and pathways which may explain this association. Our systematic review included 26 studies, mostly from high‐income countries. Nearly two‐thirds of all studies and five out of six longitudinal studies reported a statistically significant positive relationship between income inequality and risk of depression; only one study reported a statistically significant negative relationship. Twelve studies were included in a meta‐analysis with dichotomized inequality groupings. The pooled risk ratio was 1.19 (95% CI: 1.07‐1.31), demonstrating greater risk of depression in populations with higher income inequality relative to populations with lower inequality. Multiple studies reported subgroup effects, including greater impacts of income inequality among women and low‐income populations. We propose an ecological framework, with mechanisms operating at the national level (the neo‐material hypothesis), neighbourhood level (the social capital and the social comparison hypotheses) and individual level (psychological stress and social defeat hypotheses) to explain this association. We conclude that policy makers should actively promote actions to reduce income inequality, such as progressive taxation policies and a basic universal income. Mental health professionals should champion such policies, as well as promote the delivery of interventions which target the pathways and proximal determinants, such as building life skills in adolescents and provision of psychological therapies and packages of care with demonstrated effectiveness for settings of poverty and high income inequality.     

Nutritional Consequences of Wealth Differentials in East African Pastoralists: The Case of the Datoga of Northern Tanzania

Among African pastoralists evidence that wealth is associated with other measures of household success is scant and the significance of wealth differentials for family welfare remains poorly understood. Predictions that wealth in livestock is associated with increased adequacy of household food supply and with improved child nutrition are tested with longitudinal data on herd size, household composition, food supply, and anthropometric status collected in 1992 for a sample of traditional Datoga households (n = 20) living in the Eyasi basin in northern Tanzania. Although a majority subsisted below poverty cutoffs estimated for east African pastoral populations, there was large variation among households in measures of wealth and resource availability. Individuals in relatively wealthy households did not appear to benefit either in terms of adequacy of household food supply or in terms of average growth performance of young children. Theoretical and methodological challenges in the study of the relationship between wealth and health in nomadic pastoralists are discussed.     

Location Matters: Trends in Inequalities in Child Mortality in Indonesia. Evidence from Repeated Cross-Sectional Surveys

Background

Considerable improvements in life expectancy and other human development indicators in Indonesia are thought to mask considerable disparities between populations in the country. We examine the existence and extent of these disparities by measuring trends and inequalities in the under-five mortality rate and neonatal mortality rate across wealth, education and geography.

Methodology

Using data from seven waves of the Indonesian Demographic and Health Surveys, direct estimates of under-five and neonatal mortality rates were generated for 1980–2011. Absolute and relative inequalities were measured by rate differences and ratios, and where possible, slope and relative indices of inequality. Disparities were assessed by levels of rural/urban location, island groups, maternal education and household wealth.

Findings

Declines in national rates of under-five and neonatal mortality have accorded with reductions of absolute inequalities in clusters stratified by wealth, maternal education and rural/urban location. Across these groups, relative inequalities have generally stabilised, with possible increases with respect to mortality across wealth subpopulations. Both relative and absolute inequalities in rates of under-five and neonatal mortality stratified by island divisions have widened.

Conclusion

Indonesia has made considerable gains in reducing under-five and neonatal mortality at a national level, with the largest reductions happening before the Asian financial crisis (1997–98) and decentralisation (2000). Hasty implementation of decentralisation reforms may have contributed to a slowdown in mortality rate reduction thereafter. Widening inequities between the most developed provinces of Java-Bali and those of other island groupings should be of particular concern for a country embarking on an ambitious plan for universal health coverage by 2019. A focus on addressing the key supply side barriers to accessing health care and on the social determinants of health in remote and disadvantaged regions will be essential for this plan to be realised.     

The Dynamics of Wealth Inequality and the Effect of Income Distribution

The rapid increase of wealth inequality in the past few decades is one of the most disturbing social and economic issues of our time. Studying its origin and underlying mechanisms is essential for policy aiming to control and even reverse this trend. In that context, controlling the distribution of income, using income tax or other macroeconomic policy instruments, is generally perceived as effective for regulating the wealth distribution. We provide a theoretical tool, based on the realistic modeling of wealth inequality dynamics, to describe the effects of personal savings and income distribution on wealth inequality. Our theoretical approach incorporates coupled equations, solved using iterated maps to model the dynamics of wealth and income inequality. Notably, using the appropriate historical parameter values we were able to capture the historical dynamics of wealth inequality in the United States during the course of the 20th century. It is found that the effect of personal savings on wealth inequality is substantial, and its major decrease in the past 30 years can be associated with the current wealth inequality surge. In addition, the effect of increasing income tax, though naturally contributing to lowering income inequality, might contribute to a mild increase in wealth inequality and vice versa. Plausible changes in income tax are found to have an insignificant effect on wealth inequality, in practice. In addition, controlling the income inequality, by progressive taxation, for example, is found to have a very small effect on wealth inequality in the short run. The results imply, therefore, that controlling income inequality is an impractical tool for regulating wealth inequality.     

The meaning and measurement of size hierarchies in plant populations

Summary The term size hierarchy has been used frequently by plant population biologists but it has not been defined. Positive skewness of the size distribution, which has been used to evaluate size hierarchies, is inappropriate. We suggest that size hierarchy is equivalent to size inequality. Methods developed by economists to evaluate inequalities in wealth and income, the Lorenz curve and Gini Coefficient, provide a useful quantification of inequality and allow us to compare populations. A measure of inequality such as the Gini Coefficient will usually be more appropriate than a measure of skewness for addressing questions concerning plant population structure.     

Leaving your wife and your brothers: when polyandrous marriages fall apart

Polyandry challenges both traditional sociocultural and evolutionary understandings of marriage. Its existence calls into question the importance of female sexual exclusivity and reproduction in marriage, two fundamental aspects of the affinal bond in most other marital forms. How does polyandrous marriage persist? When does it dissolve? This paper examines marriage patterns in the fraternally polyandrous Tibetan communities of northwestern Nepal, highlighting the most important factors associated with both the maintenance and dissolution of polyandrous unions. Behavioral ecological analyses of polyandry to date have focused on univariate analyses of the economic and fertility correlates of the two primary marital forms observed in nominally polyandrous communities, polyandry and monogamy. In this analysis, multivariate regression and survival analysis are used to extend our understanding of the factors that precipitate partitioning among the polyandrous marriages in the study. Wealth, long thought to be a major force shaping marital decisions in these communities, is modeled in both quantity and quality in this study. This represents an important departure from previous studies, as analyses show that it is not only the amount of wealth that influences the stability of polyandrous marriages, but also the type of wealth and extent to which it is diversified over economic spheres. Univariate analyses show that amount of wealth and the size of the brother/co-husband set are both associated with the probability that a polyandrous marriage will partition. Though these results support earlier findings, multivariate analyses show that controlling for other factors reduces their importance.     

Matrilineal fertility inheritance detected in hunter-gatherer populations using the imbalance of gene genealogies

Fertility inheritance, a phenomenon in which an individual's number of offspring is positively correlated with his or her number of siblings, is a cultural process that can have a strong impact on genetic diversity. Until now, fertility inheritance has been detected primarily using genealogical databases. In this study, we develop a new method to infer fertility inheritance from genetic data in human populations. The method is based on the reconstruction of the gene genealogy of a sample of sequences from a given population and on the computation of the degree of imbalance in this genealogy. We show indeed that this level of imbalance increases with the level of fertility inheritance, and that other phenomena such as hidden population structure are unlikely to generate a signal of imbalance in the genealogy that would be confounded with fertility inheritance. By applying our method to mtDNA samples from 37 human populations, we show that matrilineal fertility inheritance is more frequent in hunter-gatherer populations than in food-producer populations. One possible explanation for this result is that in hunter-gatherer populations, individuals belonging to large kin networks may benefit from stronger social support and may be more likely to have a large number of offspring.