Polygamy and child mortality: Historical and modern evidence from Nigeria’s Igbo

Abstract

We use historical and modern data on the Igbo ethnic group in Nigeria to assess the relationship between polygamy and child mortality. We examine several possible channels for this correlation, and test its sensitivity to observable characteristics of individuals, households, and regions in order to infer the scope for selection on unobservables to drive the polygamy-child mortality correlation. We find a statistically significant positive relationship between polygamy and child mortality in the modern period, and a statistically insignificant positive relationship in the historical data. Although there is a limited role for polygamist-specific intrahousehold dynamics and behavioral practices in shaping the mortality of children in such households, the sensitivity of the polygamy-child mortality correlation is consistent with an important role for selection into polygamy, particularly on unobservable characteristics.

Polygynous marriage and child health in sub-Saharan Africa: What is the evidence for harm?

“…Ethnographic evidence is consistent with sharing a husband causing emotional distress in many contexts, although the situation is clearly culturally variable (Jankowiak, Sudakov, and Wilereker 2005;Meekers and Franklin 1995). It is also possible that cowife competition leads to relative inefficiency in resource production and consumption compared to hypothetically more harmonious monogamous unions, in turn reducing child health (discussed in Arthi and Fenske 2018). Henrich, Boyd, and Richerson (2012) further hypothesize that normative polygyny has negative society-wide consequences for child wellbeing because, according to their reasoning, it (i) incentivizes strategies of reduced paternal care, with men preferring to divert their resources into accumulating additional wives rather than into raising existing offspring, and (ii) increases the propensity for social unrest driven by a larger pool of unmarried men.…”

“…However, they find no difference in the likelihood of children receiving medical treatment for fever or diarrhea. Arthi and Fenske (2018) report that polygyny is negatively associated with a range of indicators of early life care in a Nigerian DHS. However, they also report that "controlling for maternal education and the DHS wealth index is sufficient to make many of these correlations statistically insignificant, suggesting that the failure of polygamous mothers to invest in early-childhood medical care may reflect selection into polygamy more so than it reflects a polygamist-specific cultural practice" (Arthi and Fenske 2018: 124).…”

“…This discrepancy, especially when combined with systematic remarriage after divorce and widowhood, also ensures that, even when polygyny is very common, the vast majority of men marry. Arthi and Fenske (2018), based on the most recent DHS surveys, estimate that across Africa one in four married women are in polygynous marriages, and about the same fraction of children under 14 years were born to polygynous mothers. Bove and Valeggia (2009), based on DHS data available at the time of publication, estimate that the percentage of married women aged 15-49 years in a polygynous marriage varies from a low of 11% in Zimbabwe, to a median of 27% in the Ivory Coast, to a high of 53% in Guinea.…”

“…In populations where variation in material wealth is lacking (e.g., relatively egalitarian huntergatherers), physical or social capital may be more important in determining which men take multiple wives (e.g., in Congolese foragers: Chaudhary et al 2015). Several studies have also presented evidence that polygyny is associated with stratification among women in competition for marriage placements, with, for example, relatively lower status women most likely to sort into polygynous marriages, particularly as second or later wives (e.g., in Ethiopia: Matz 2016; Mace 2007, in Nigeria: Arthi andFenske 2018). In Ethiopia for example, Matz (2016) reports that first wives have wealthier family backgrounds than later wives, while Gibson and Mace (2007) suggest that stratification is indicated by differences in the bridewealth transfers exchanged at entrance to initially monogamous vs. polygynous marriages, with higher bridewealth for first wives compared to second or later wives.…”

“…Antoine and Nanitelamio (1996) report a similar lack of socioeconomic differences between monogamous and polygynous individuals in urban Senegal. While the types of individuals that are most likely to experience polygyny may vary, and the patterns are not always well understood, the relevant implication for this review is that any degree of non-random selection into polygyny undermines our ability to infer causality in correlational studies of polygyny and child health (see also discussion in: Arthi and Fenske 2018;Gibson and Mace 2007;Matz 2016).…”