Showoffs or Providers? The Parenting Effort of Hadza Men

Paternal care plays an important role in many scenarios of human evolution. Lately, however, this “Man the Provisioner” view has been challenged. The showoff hypothesis, for example, proposes that men hunt not to provision children but to gain extra mating opportunities, and some have suggested that male care among mammals is always a form of mating, rather than parenting, effort. This study, based on observation in a hunting and gathering society, the Hadza of Tanzania, tests whether men provide care as parenting effort. If male care were mating effort only, stepchildren should receive no less care than biological children. My data, however, reveal that stepchildren do receive less care. This suggests that care is provided, at least in part, as parenting effort. Although lower direct care implies stepfathers are less motivated to care for stepchildren, resource acquisition data raise the question of whether stepfathers are less motivated, or simply less skilled.     

Services d’éducation préscolaire et comportements agressifs : un rôle de prévention pour les familles vulnérables

Context

Physical violence is a significant problem in health terms and for society as a whole. Many studies have shown that socio-economic indicators such as poverty and poor parental educational attainment are associated with an increased risk of difficulties in social adjustment of the child. The hypothesis of this study was that the pre-school educational services (PES) could help to prevent the development of physical aggression (PA) in the children of vulnerable families, and that this would depend on the age at which the child first had access to the service.

Methods

Identification of children presenting with a pattern of increased PA between 17 and 60 months of age, taken from a representative sample of children born in Quebec (N = 1691). We took into consideration the educational level of the mother and the age at which the child started to receive PES. We examined the association of these factors with the PA group to which the child belonged, while controlling against several other family characteristics which are associated with PES and PA.

Results

The children of mothers with a low level of educational attainment (no secondary school qualification) were less likely to have received PES than the others. Those who had received such attention had a considerably reduced risk of displaying a behaviour pattern of increased PA. The results of multiple logistic regression analysis revealed that the PES reduced the risk of high PA, especially if the child was exposed to the service before the age of 9 months (d = ?0.62; SD = 0.24; 95% CI: ?1.09 to ?0.16; odds ratio = 0.20; 95% CI: 0.05–0.9). Children whose mothers had obtained a secondary school diploma were at reduced risk of high PA. For them, the PES did not represent an additional protective factor.

Interpretation

PES directed towards children of poorly educated mothers might reduce considerably the risk of chronic physical aggression, especially if initiated soon after birth. As those children who aremost likely to benefit from PES are the least likely to receive it, it is necessary to put special measures in place to direct this sort of service towards at risk families.     

The life histories of American stepfathers in evolutionary perspective

This paper presents an analysis of the characteristics of men who become stepfathers, and their subsequent fertility patterns and lifetime reproductive success. Because women who already have children are ranked lower in the marriage market than women without children, men who marry women with children (e.g., stepfathers) are likely to have lower rankings in the marriage market as well. Using retrospective fertility and marital histories from the Panel Study of Income Dynamics (PSID), I show that men who become stepfathers have lower levels of education, less income, and are more likely to have been divorced before and to already have children, all characteristics that lower their rankings in the marriage market. Men with one or two stepchildren are just as likely to have children within a marriage as non-stepfathers, although men with three stepchildren show decreased fertility. Among men age 45 and older, stepfathers have lower lifetime fertility than non-stepfathers, although the difference disappears when men’s age at first marriage is controlled for. Additionally, stepfathers have significantly higher fertility than men who never marry. The results suggest that some men become stepfathers to procure mates and fertility benefits that they would otherwise have been unlikely to obtain; for these men, raising other men’s children serves as a form of mating effort. Preliminary versions of this paper were presented at the Evolution and Human Adaptation Program at the University of Michigan, and the Human Behavior and Evolution Society’s annual meeting at Amherst. Kermyt G. Anderson received his Ph.D. in anthropology from the University of New Mexico in 1999. He is currently a Mellon Postdoctoral Research Fellow at the Population Studies Center of the Institute for Social Research at the University of Michigan. His current research examines the relationship between family structure, parental investment, and children’s educational and employment outcomes in South Africa.     

Growth and Fluctuating Asymmetry of Stepchildren

Parental caretaking is critical for child health and psychological development. Evolutionary logic and empirical studies suggest that stepchildren sometimes may receive less care and experience more traumas than genetic offspring. In this article, we investigate the effects of stepfamily environment on children's physical growth as part of a 12-year (1988–1999) project investigating child health in a rural village on the east coast of Dominica. Participants were 238 children aged 0–20 (X = 10.53) residing in the village of Bwa Mawego. Information on family environments was collected continuously since 1988. Here we analyze data from a longitudinal series of anthropometric measures collected in 1997, 1998, and 1999. To assess general growth, we measured height, weight, head circumference, triceps skinfold, subscapular skinfold, and peri-umbilical skinfold. We also collected medical records of weight from birth through 3 years of age. To assess fluctuating asymmetry (FA), we measured bilateral (right and left side) arm circumference, calf circumference, wrist breadth, ankle breadth, ear breadth, ear height, and length of digits 2–5. Coresidence with stepfather was associated with suboptimal growth. Female stepchildren aged 0–10 and male stepchildren aged 10–20 had lower body weight for age than other children, including their coresident half-siblings. Stepchildren and nonstepchildren had similar weights at birth, and similar muscle and fat cross-sections. Contrary to expectations, FA of stepchildren was lower than in other children. Recognition of the high risk of poor growth for stepchildren is important because of subsequent associations with morbidity, psychological problems, and educational performance. Why stepchildren had significantly lower FA than others warrants further investigation.     

Confidence of paternity,divorce, and investment in children by Albuquerque men

Using a sample of men living in Albuquerque, NM, we examined the relationship between paternity confidence and men's investment in children. In humans, men may reduce their investment in a child in two ways: indirectly, by ending their relationship with the child's mother and ceasing to cohabit with the child (e.g., divorce), and directly, by allocating less time and fewer resources to the child. In this article, we tested two hypotheses regarding the effect of paternity confidence on investment in children: (1) men will be more likely to divorce women if they suspect or are sure that they are not the father of their wife's child, and (2) controlling for divorce, men will reduce direct investments in low paternity confidence children relative to high paternity confidence children. The first hypothesis was supported by the data. The second hypothesis was supported for two out of three measures of paternal investment we examined; low paternity confidence reduces the time men spend with a child in a group with other children or adults, and it reduces extensive involvement with the child's educational progress; there was no effect of paternity confidence on the amount of time men spend with children in one-on-one interactions. We also examined the effects of unstated paternity confidence (e.g., when men decline to answer the question) on divorce and paternal investment. Overall, the results suggested that paternity confidence plays an important role in shaping men's relationships with women and with their putative genetic children.     

Marital Dissolution and Child Educational Outcomes in San Borja,Bolivia

Serial monogamy is likely an adaptive mating strategy for women when the expected future fitness gains with a different partner are greater than expected future fitness with one’s current partner. Using interview data from more than 400 women in San Borja, Bolivia, discrete-time event history analyses and random effects regression analyses were conducted to examine predictors of marital dissolution, separated by remarriage status, and child educational outcomes. Male income was found to be inversely associated with women’s risk of “divorce and remarriage,” whereas female income is positively associated with women’s risk of “divorce, but not remarriage.” Children of women who divorce and remarry tend to have significantly lower educational outcomes than children of married parents, but women with higher incomes are able to buffer their children from the negative educational outcomes of divorce and remarriage. Counter to predictions, there is no evidence that women with kin in the community have a significant difference in likelihood of divorce or a buffering effect of child outcomes. In conclusion, predictors of divorce differ depending on whether the woman goes on to remarry, suggesting that male income may be a better predictor of a serial monogamy strategy whereas female income predicts marital dissolution only. Thus, women who are relatively autonomous because of greater income may not benefit from remarriage.     

Paternal investment and status-related child outcomes: timing of father's death affects offspring success

Recent work in human behavioural ecology has suggested that analyses focusing on early childhood may underestimate the importance of paternal investment to child outcomes since such investment may not become crucial until adolescence or beyond. This may be especially important in societies with a heritable component to status, as later investment by fathers may be more strongly related to a child's adult status than early forms of parental investment that affect child survival and child health. In such circumstances, the death or absence of a father may have profoundly negative effects on the adult outcomes of his children that cannot be easily compensated for by the investment of mothers or other relatives. This proposition is tested using a multigenerational dataset from Bangalore, India, containing information on paternal mortality as well as several child outcomes dependent on parental investment during adolescence and young adulthood. The paper examines the effects of paternal death, and the timing of paternal death, on a child's education, adult income, age at marriage and the amount spent on his or her marriage, along with similar characteristics of spouses. Results indicate that a father's death has a negative impact on child outcomes, and that, in contrast to some findings in the literature on father absence, the effects of paternal death are strongest for children who lose their father in late childhood or adolescence.     

PRegnancy Outcomes after a Maternity Intervention for Stressful EmotionS (PROMISES): study protocol for a randomised controlled trial

Background

There is ample evidence from observational prospective studies that maternal depression or anxiety during pregnancy is a risk factor for adverse psychosocial outcomes in the offspring. However, to date no previous study has demonstrated that treatment of depressive or anxious symptoms in pregnancy actually could prevent psychosocial problems in children. Preventing psychosocial problems in children will eventually bring down the huge public health burden of mental disease. The main objective of this study is to assess the effects of cognitive behavioural therapy in pregnant women with symptoms of anxiety or depression on the child's development as well as behavioural and emotional problems. In addition, we aim to study its effects on the child's development, maternal mental health, and neonatal outcomes, as well as the cost-effectiveness of cognitive behavioural therapy relative to usual care.

Methods/design

We will include 300 women with at least moderate levels of anxiety or depression at the end of the first trimester of pregnancy. By including 300 women we will be able to demonstrate effect sizes of 0.35 or over on the total problems scale of the child behavioural checklist 1.5-5 with alpha 5% and power (1-beta) 80%.Women in the intervention arm are offered 10-14 individual cognitive behavioural therapy sessions, 6-10 sessions during pregnancy and 4-8 sessions after delivery (once a week). Women in the control group receive care as usual.Primary outcome is behavioural/emotional problems at 1.5 years of age as assessed by the total problems scale of the child behaviour checklist 1.5 - 5 years.Secondary outcomes will be mental, psychomotor and behavioural development of the child at age 18 months according to the Bayley scales, maternal anxiety and depression during pregnancy and postpartum, and neonatal outcomes such as birth weight, gestational age and Apgar score, health care consumption and general health status (economic evaluation).

Trial Registration

Netherlands Trial Register (NTR): NTR2242

     

Testosterone and Jamaican Fathers

This paper investigates relationships between men’s testosterone and family life in a sample of approximately 350 Jamaican fathers of children 18–24 months of age. The study recognizes the role of testosterone as a proximate mechanism coordinating and reflecting male life history allocations within specific family and cultural contexts. A sample of Jamaican fathers and/or father figures reported to an assessment center for an interview based on a standardized questionnaire and provided a saliva sample for measuring testosterone level. Outcomes measured include subject demographics such as age and relationship status as well as partnership quality and sexuality and paternal attitudes and behavior. The variation in these fathers’ relationship status (e.g., married co-residential fathers, fathers in new non-residential relationships) was not associated with men’s testosterone. Too few stepfathers participated to enable a direct test of the prediction that stepfathers would have higher testosterone than biological fathers, although fathers who reported living with partners’ (but not his own) children did not have higher testosterone than fathers not reporting residing with a non-biological child. Fathers’ relationship quality was negatively related to their testosterone. Measures of paternal attitudes and behavior were not related to fathers’ testosterone. Consistent with previous ethnography, this sample of Jamaican fathers exhibited variable life history profiles, including residential status. We discuss why fathers’ relationship quality was found to be negatively related to their testosterone level, but other predictions were not upheld.     

The “Long-arm” of chronic conditions in childhood: Evidence from Canada using linked survey-administrative data

The objective of this study was to investigate the relationship between health conditions in childhood (ages 4–11), and health and socioeconomic outcomes in adulthood (ages 21–33). This study takes advantage of a new linkage between the National Longitudinal Survey of Children and Youth (NLSCY) and administrative tax data from the T1 Family File (T1FF) from Statistics Canada. The NLSCY includes rich longitudinal information on child development, while the T1FF includes administrative tax information on each child in adulthood (e.g., income, social assistance). The primary measures of child health relate to the diagnosis of a chronic condition, affecting the child’s physical or mental/developmental health. The results suggest that mental/developmental health conditions in childhood more negatively influence adult health and socioeconomic conditions, compared to physical health conditions. Interaction models reveal modest heterogenous effects; for example, there is some evidence of a cushioning effect from higher household income in childhood, as well as an exacerbating negative effect from lower birth weight for mental/developmental health conditions. Using a covariate decomposition approach to explore underlying pathways, the results reveal that associations between health in early life and outcomes in adulthood are partially explained by differences in cognitive skills (i.e., mathematics test scores) in adolescence (ages 16–17). Results may encourage policy investments to mitigate the occurrence of health conditions in childhood and to ensure timely access to educational supports and health services for children with chronic conditions.     

Family Type and Investment in Education: A Comparison of Genetic and Stepparent Families

Data from the U.S. National Education Longitudinal Survey were examined to investigate postsecondary educational investment in two-parent families. Consistent with hypotheses derived from the logic of inclusive fitness theory, contrasting children with two genetic parents with children from stepparent households on a multivariate composite of investment indicators revealed that stepchildren receive significantly less parental support for pursuit of higher education. Univariate tests on the three measures comprising the multivariate composite indicated that relative to children with two genetic parents, stepchildren have parents who (1) delay the start of savings accounts for postsecondary education, (2) put aside less money for subsidizing the costs of higher education, and (3) expect to allocate fewer economic resources to support the first year of postsecondary schooling. Statistical control of child ability, resource availability, and number of family members sharing in parental resources was accomplished in a second multivariate analysis by using child achievement, familial socioeconomic status, and number of financial dependents in each family as covariates. Statistically equating genetic and stepparent families on these measures reduced, but did not eliminate, the investment differences.     

Social media use and emotional and behavioural outcomes in adolescence: Evidence from British longitudinal data

We investigate the relationship between social media use and emotional and behavioural outcomes in adolescence using data from a large and detailed longitudinal study of teenagers from the UK. We use individual fixed effects, propensity score matching and treatment effects with Inverse Probability Weighted Regression Adjustment, controlling for a rich set of children’s and family’s characteristics and using comprehensive sensitivity analyses and tests to assess the potential role of unobserved variables. Our results show that prolonged use of social media (more than 4 hours per day) is significantly associated with poor emotional health and increased behavioural difficulties, and in particular decreased perception of self-value and increased incidence of hyperactivity, inattention and conduct problems. However, limited use of social media (less than 3 h per day) compared to no use has some moderate association with positive peer relationships.     

Differential parental investment in families with both adopted and genetic children

Stepchildren are abused, neglected and murdered at higher rates than those who live with two genetically related parents. Daly and Wilson used kin selection theory to explain this finding and labeled the phenomenon “discriminative parental solicitude.” I examined discriminative parental solicitude in American households composed of both genetic and unrelated adopted children. In these families, kin selection predicts parents should favor their genetic children over adoptees. Rather than looking at cases of abuse, neglect, homicide and other antisocial behavior, I focused on the positive investments parents made in their children as well as the outcomes of each child. The results show that parents invested more in adopted children than in genetically related ones, especially in educational and personal areas. At the same time, adoptees experienced more negative outcomes. They were more likely to have been arrested, to have been on public assistance and to require treatment for drug, alcohol or mental health issues. They also completed fewer years of schooling and were more likely to divorce. In adoptive families, it appears that “the squeaky wheel gets the grease.” Parents invest more in adoptees not because they favor them, but because they are more likely than genetic children to need the help. I conclude that discriminative parental solicitude differs in adoptive and step households because adoptive families generally result from prolonged parenting effort, not mating effort like stepfamilies.     

The impact of educational rewards on the diagnosis of autism spectrum disorder

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that affects social interactions and communication. The prevalence of ASD has risen dramatically in recent years, but the underlying factors leading to this rise are not clear. In this paper, we test whether changes in state-level educational policy that impact school-level resources are associated with the rise in ASD diagnostic prevalence. Early identification of ASD can improve an array of outcomes for children, and school systems play an important role with identification of the condition. It is plausible that children attending schools with better resources from state governments are more likely to receive an ASD diagnosis and presumably appropriate services. We focus on one educational policy in particular, state-level rewards, which consist of a monetary transfer from state governments to school districts. To test the impact of educational rewards on ASD diagnosis, we rely on policy variation across states and time and estimate both two-way fixed effects (TWFE) models alongside recently advanced methods in the difference-in-differences (DiD) literature. Under a baseline TWFE specification we estimate that rewards policies are associated with a 18.46% increase in ASD diagnosis. Further, using DiD methods that account for bias in settings of differential policy timing, we find that the magnitude of the effect increases to 24.8%. We believe these findings to be suggestive evidence that educational rewards policies improved the likelihood of detection and diagnosis of ASD.     

Helpful grandmothers in rural Ethiopia: A study of the effect of kin on child survival and growth

Kin selection and parental investment theories state that, in highly social species, such as humans, individuals can increase their inclusive fitness by extending support to their relatives. Here, we document patterns of kin support in a rural Ethiopian community, where postmarital residence practices provide differential access to relatives. Using demographic, anthropometric, and behavioral data collected from four villages we are able to (a) identify the effects of the presence of kin on child mortality and growth patterns and (b) provide detailed information on the role of relatives within the household.

Mortality analyses indicate that grandmothers had a positive effect on child survival. Anthropometric data reveal that maternal grandmothers had a particularly beneficial effect on child height, but paternal grandmothers less so. Time allocation data suggest that grandmothers continued to visit their daughters' households, irrespective of postmarital residence, where they relieved their daughters of heavy domestic tasks rather than helping with direct grandchild care. Matrilocal postmarital residence was associated with improved child survival, although children in matrilocal households were actually smaller. This may be due to wealth effects, increased competition between siblings, or higher survival of smaller infants in matrilocal households.     

The effect of low birth weight on height,weight and behavioral outcomes in the medium-run

A number of studies have documented negative long term effects of low birth weight. Yet, not much is known about the dynamics of the process leading to adverse health and educational outcomes in the long run. While previous studies focusing mainly on LBW effects on physical growth and cognitive outcomes have found effects of the same size at both school age and young adulthood, others have found a diminishing negative effect over time. The purpose of this paper was to bring new evidence to this issue by analyzing the medium run effects of low birth weight on child behavioral outcomes as well as physical growth at ages 6 months, 3½, 7½ and 11 years using data from the Danish Longitudinal Survey of Children. Observing the same children at different points in time enabled us to chart the evolution of anthropometric and behavioral deficits among children born with low birth weight and helped understanding the nature and timing of interventions.     

Mechanisms of Resilience in Children of Mothers Who Self-Report with Depressive Symptoms in the First Postnatal Year

Background

Symptoms of maternal postnatal depression are associated with an increased risk of adverse effects on child development. However, some children exposed to postnatal depression have outcomes similar to unexposed children, and can be referred to as resilient. This study aimed to determine the mechanisms of resilience in children exposed to depressive symptoms postnatally.

Method

Data are from a prospective cohort study, the Avon Longitudinal Study of Parents and Children. Self-report questionnaire data were collected during pregnancy and the child’s first 2 years regarding maternal views of parenting and her perception of the child. The Edinburgh Postnatal Depression Scale (EPDS) was completed postnatally at 8 months and the Strengths and Difficulties Questionnaire (SDQ) at age 11 years. Exposed children who scored above the median score of non-exposed children were defined as resilient. Structural equation modeling was used to investigate the development of resilience.

Results

From the core ALSPAC cohort, 1,009 children (6.9%) were exposed to maternal depression at 8 months postnatally. The SDQ total difficulties scores at 11 years of age indicated that 325 (32.2%) were resilient, 684 were non-resilient. Maternal positive feelings about parenting and child non-verbal communication at 15 months increased the likelihood of later resilience.

Conclusions

In this study, resilience was associated with two factors: the child’s nonverbal communication at 15 months and by maternal positive feelings about parenting. Early intervention to support mother-child interaction and foster child development in women identified with postnatal depressive symptoms may benefit later child resilience.     

Do intestinal nematodes affect productivity in adulthood?

Intestinal nematode infections have been associated with many physical and mental developmental insults. These include anaemia, wasting, stunting, cognitive impairment and lowered educational achievement, all of which have in turn been shown to interfere with productivity and wage-earning capacity in adults. Although there is no direct evidence for an effect of intestinal nematodes on productivity, circumstantial evidence suggests such an effect. Here, Helen Guyatt reviews the indirect evidence for an effect of intestinal nematodes on productivity in adults through current infection and associated morbidity, and on early ill-health in children, which might affect productivity later in life.     

The Use of Multiple Outcomes Analysis in Neurotoxicity: An Example from the New Zealand Study of Offspring of Mothers Exposed to Methyl Mercury

Neurotoxicity has become an important area in the study of the risk to children of noncarcinogens. Many of the tests used to evaluate neurotoxic effects in neurotoxic studies are psychometric tests to assess cognitive, motor, and perceptual performance in individuals in order to determine the presence of psychological problems, impaired educational achievement, or neurological abnormalities. The underlying assumption of these procedures are that a test performance deficit is indicative of a neurological disability, and that such disability derives from the prenatal exposure to an offending substance. The usual analytic paradigm for discerning environmental impacts is to analyze the scores of a particular subtest in a battery taken separately as the dependent variable with regression analysis, which adjusts for cultural background, educational level, and socioeconomic status. The impact of this analysis is to determine the correlation of each of the psychometric test results to exposure. We show a statistical method to simultaneously analyze the multiple outcomes of many tests using General Estimating Equations (GEE) to determine if a correlation exists between the global measure of all these tests and exposure adjusted for covariates of interest and the correlation among the dependent psychometric variables. We show the application of this method to the results of children whose mothers were exposed to mercury during pregnancy.     

Covariates of child mortality in Mali: does the health-seeking behaviour of the mother matter?

This paper uses data from the 1995/96 Mali DHS survey to examine the importance of a wide range of socioeconomic, behavioural and biodemographic factors in the determination of child mortality in Mali, with a special focus on maternal education and behaviour. The central hypothesis of the study is that advances in maternal education would contribute little to child survival in settings such as Mali's urban and rural communities where progress in educational attainment is not matched with improvements in other aspects of socioeconomic development such as economic growth, job creation, financial security and public health and medical resources. Units of analysis are children born in the past 5 years to DHS respondents (women aged 15-45) who were married at the time of the survey. The Cox proportional hazards regression technique has been used to estimate the net effects of variables included as covariates. The findings indicate that the health-seeking behaviour of the mother matters more than maternal education in explaining the observed differences in infant and child mortality in Mali's urban and rural areas.