Evaluation of a tablet-based assessment tool for measuring cognition among children 4-6 years of age in Ghana.

OBJECTIVES: To investigate several basic psychometric properties, including construct, convergent and discriminant validity, of the tablet-based Rapid Assessment of Cognitive and Emotional Regulation (RACER) among children aged 4-6 years in Ghana. METHODS: We investigated whether RACER tasks administered to children in Ghana could successfully reproduce expected patterns of performance previously found in high-income countries on similar tasks assessing inhibitory control (e.g., slower responses on inhibition trials), declarative memory (e.g., higher accuracy on previously seen items), and procedural memory (e.g., faster responses on sequence blocks). Next, we assessed the validity of declarative memory and inhibitory control scores by examining associations of these scores with corresponding paper-based test scores and increasing child age. Lastly, we examined whether RACER was more sensitive than paper-based tests to environmental risk factors common in low- and middle-income countries (LMICs). RESULTS: Of the 966 children enrolled, more than 96% completed the declarative memory and inhibitory control tasks; however, around 30% of children were excluded from data analysis on the procedural memory task due to missing more than half of trials. The performance of children in Ghana replicated previously documented patterns of performance. RACER inhibitory control accuracy score was significantly correlated with child age (r (929) = .09, p = .007). However, our findings did not support other hypotheses. CONCLUSIONS: The high task completion rates and replication of expected patterns support that certain RACER sub-tasks are feasible for measuring child cognitive development in LMIC settings. However, this study did not provide evidence to support that RACER is a valid tool to capture meaningful individual differences among children aged 4-6 years in Ghana.

Brazil's Missing Infants: Zika Risk Changes Reproductive Behavior.

Zika virus epidemics have potential large-scale population effects. Controlled studies of mice and nonhuman primates indicate that Zika affects fecundity, raising concerns about miscarriage in human populations. In regions of Brazil, Zika risk peaked months before residents learned about the epidemic and its relation to congenital anomalies. This spatiotemporal variation supports analysis of both biological effects of Zika infection on fertility and the effects of learning about Zika risk on reproductive behavior. Causal inference techniques used with vital statistics indicate that the epidemic caused reductions in birth cohort size of approximately one-quarter 18 months after Zika infection risk peaked but 10 months after public health messages advocated childbearing delay. The evidence is consistent with small but not statistically detectable biological reductions in fecundity, as well as large strategic changes in reproductive behavior to temporally align childbearing with reduced risk to infant health. The behavioral effects are larger for more-educated and older women, which may reflect facilitated access to information and to family planning services within high-risk, mosquito-infested urban locations as well as perceptions about the opportunity costs of risks to pregnancy and infant survival.

Minds Under Siege: Cognitive Signatures of Poverty and Trauma in Refugee and Non-Refugee Adolescents.

The impacts of war and displacement on executive function (EF)-what we might call the cognitive signatures of minds under siege-are little known. We surveyed a gender-balanced sample of 12- to 18-year-old Syrian refugees (n = 240) and Jordanian non-refugees (n = 210) living in Jordan. We examined the relative contributions of poverty, trauma exposure, posttraumatic stress, and insecurity to variance in inhibitory control and working memory. We observed associations between poverty and WM, suggesting that, even in populations exposed to substantial violence and fear, poverty is a specific pathway to WM deficit. We did not, however, find associations between EFs and exposures to trauma. Careful distinction between childhood adversities may illuminate which neurocognitive pathways matter for measures of cognitive function.

Detecting the Effects of Early-Life Exposures: Why Fecundity Matters.

Prenatal exposures have meaningful effects on health across the lifecourse. Innovations in causal inference have shed new light on these effects. Here, we motivate the importance of innovation in the characterization of fecundity, and prenatal selection in particular. We argue that such innovation is crucial for expanding knowledge of the fetal origins of later life health. Pregnancy loss is common, responsive to environmental factors, and closely related to maternal and fetal health outcomes. As a result, selection into live birth is driven by many of the same exposures that shape the health trajectories of survivors. Lifecourse effects that are inferred without accounting for these dynamics may be significantly distorted by survival bias. We use a set of Monte Carlo simulations with realistic parameters to examine the implications of prenatal survival bias. We find that even in conservatively specified scenarios, true fetal origin effects can be underestimated by 50% or more. In contrast, effects of exposures that reduce the probability of prenatal survival but improve the health of survivors will be overestimated. The absolute magnitude of survival bias can even exceed small effect sizes, resulting in inferences that beneficial exposures are harmful or vice-versa. We also find reason for concern that moderately sized true effects, underestimated due to failure to account for selective survival, are missing from scientific knowledge because they do not clear statistical significance filters. This bias has potential real-world costs; policy decisions about interventions to improve maternal and infant health will be affected by underestimated program impact.

Endogenous coresidence and program incidence: South Africa's Old Age Pension.

We investigate whether living arrangements respond to an arguably exogenous shift in the distribution of power in family economic decision-making. In the early 1990s, the South African Old Age Pension was expanded to cover most black South Africans above a sex-specific age cut-off resulting in a substantial increase in the income of older South Africans and potentially their say in the economic decisions of their families. Beneficiaries of the program are more likely to coreside with adults who have less human capital as measured by height and education. Since height and education are fixed for adults, this cannot be an effect of the pension income but reflects selective changes in living arrangements resulting from the pension. The findings highlight the endogeneity of living arrangements and illustrate the potential value of moving beyond theory and data that are confined to a spatially determined definition of the household.

Do daughters really cause divorce? Stress, pregnancy, and family composition.

Provocative studies have reported that in the United States, marriages producing firstborn daughters are more likely to divorce than those producing firstborn sons. The findings have been interpreted as contemporary evidence of fathers' son preference. Our study explores the potential role of another set of dynamics that may drive these patterns: namely, selection into live birth. Epidemiological evidence indicates that the characteristic female survival advantage may begin before birth. If stress accompanying unstable marriages has biological effects on fecundity, a female survival advantage could generate an association between stability and the sex composition of offspring. Combining regression and simulation techniques to analyze real-world data, we ask, How much of the observed association between sex of the firstborn child and risk of divorce could plausibly be accounted for by the joint effects of female survival advantage and reduced fecundity associated with unstable marriage? Using data from the National Longitudinal Survey of Youth (NLSY79), we find that relationship conflict predicts the sex of children born after conflict was measured; conflict also predicts subsequent divorce. Conservative specification of parameters linking pregnancy characteristics, selection into live birth, and divorce are sufficient to generate a selection-driven association between offspring sex and divorce, which is consequential in magnitude. Our findings illustrate the value of demographic accounting of processes which occur before birth-a period when many outcomes of central interest in the population sciences begin to take shape.

Housing wealth, psychological well-being, and cognitive functioning of older Americans.

OBJECTIVES: Economic security around retirement age may be an important determinant of psychological and cognitive well-being of older adults. This study examines the impact of the dramatic increase in housing prices from the mid-1990s to the mid-2000s on psychological and cognitive outcomes among Americans born between 1924 and 1960. METHOD: Our quasi-experimental empirical strategy exploits geographic differences in housing market price trends during the housing boom (from the mid-1990s until 2006). We use individual-level data from the Health and Retirement Study (HRS) and estimates of housing values from DataQuick, a California-based real estate consultancy firm, to estimate the association of housing price increases with psychological and cognitive outcomes at follow-up. RESULTS: Greater housing appreciation over the follow-up period was associated with a significantly lower risk of anxiety (for women) and an improved performance on some but not all cognitive tasks. Effects for depressive symptoms, positive and negative affect, and life satisfaction were all in the beneficial direction but not statistically significant. The effects of price run-ups were concentrated on homeowners, as opposed to renters, suggestive of wealth-driven effects. DISCUSSION: Housing market volatility may influence the psychological and cognitive health of older adults, highlighting potential health consequences of pro-home ownership policies, which may be especially important in light of recent dramatic housing price declines.

Physical health effects of the housing boom: quasi-experimental evidence from the health and retirement study.

OBJECTIVES: We examined the impact of the dramatic increases in housing prices in the United States in the 1990s and early 2000s on physical health outcomes among a representative sample of middle-aged and older Americans. METHODS: Using a quasi-experimental design, we exploited geographic and time variation in housing prices using third-party valuation estimates of median single-family detached houses from 1988 to 2007 in each of 2400 zip codes combined with Health and Retirement Study data from 1992 to 2006 to test the impact of housing appreciation on physical health outcomes. RESULTS: Respondents living in communities in which home values appreciated more rapidly had fewer functional limitations, performed better on interviewer-administered physical tasks, and had smaller waist circumference. CONCLUSIONS: Our results indicate that increases in housing wealth were associated with better health outcomes for homeowners in late middle age and older. The recent sharp decline in housing values for this group may likewise be expected to have important implications for health and should be examined as data become available.

The effect of water quality testing on household behavior: evidence from an experiment in rural India.

How does specific information about contamination in a household's drinking water affect water handling behavior? We randomly split a sample of households in rural Andhra Pradesh, India. The treatment group observed a contamination test of the drinking water in their own household storage vessel; while they were waiting for their results, they were also provided with a list of actions that they could take to remedy contamination if they tested positive. The control group received no test or guidance. The drinking water of nearly 90% of tested households showed evidence of contamination by fecal bacteria. They reacted by purchasing more of their water from commercial sources but not by making more time-intensive adjustments. Providing salient evidence of risk increases demand for commercial clean water.

Exploring the causal machinery behind sex ratios at birth: does hepatitis B play a role?

The causal machinery underlying sex determination is directly relevant to many questions relating gender and family composition to social and economic outcomes. In recent work, Oster highlighted a correlation between parental hepatitis B carrier status and sex of the child. One of her analyses went further, speaking directly to causality. That analysis appeared to have answered an important question that had remained unresolved in medical and biological literatures­namely, does chronic infection with hepatitis B cause male­skewed sex ratios at birth? Oster's creative empirical analysis appeared to suggest that it does; however, in this article I reassess the result and present evidence that, at the very least, the question remains open. Further investigation into questions around the causal machinery of sex determination is warranted in the social science literature, as well as in that of biology and medicine. However, my results suggest that it is extremely unlikely that chronic hepatitis B infection plays a biologically significant role.