Kevin Lewis

June 27, 2017

The Sibsize Revolution and Social Disparities in Children’s Family Contexts in the United States, 1940–2012
Tony Fahey
Demography, June 2017, Pages 813–834


This article points to a sharp decline in children’s sibling numbers (sibsize) that occurred in the United States since the 1970s and was large enough among children with lower socioeconomic status (SES) (particularly black children) to amount to a revolution in their family circumstances. It interprets sibsize decline as a source of social convergence in children’s family contexts that ran counter to trends toward social divergence caused by the rise of lone parenthood. The article is based on new estimates of differences in children’s sibsize and lone parenthood by race and maternal education generated from public-use samples from the Census of Population and Current Population Survey (CPS), focusing especially on the period 1940–2012. I discuss some methodological and substantive challenges for existing scholarship arising from the findings and point to questions for future research.

Offspring of parents who were separated and not speaking to one another have reduced resistance to the common cold as adults
Michael Murphy et al.
Proceedings of the National Academy of Sciences, 20 June 2017, Pages 6515–6520


Exposure to parental separation or divorce during childhood has been associated with an increased risk for physical morbidity during adulthood. Here we tested the hypothesis that this association is primarily attributable to separated parents who do not communicate with each other. We also examined whether early exposure to separated parents in conflict is associated with greater viral-induced inflammatory response in adulthood and in turn with increased susceptibility to viral-induced upper respiratory disease. After assessment of their parents’ relationship during their childhood, 201 healthy volunteers, age 18–55 y, were quarantined, experimentally exposed to a virus that causes a common cold, and monitored for 5 d for the development of a respiratory illness. Monitoring included daily assessments of viral-specific infection, objective markers of illness, and local production of proinflammatory cytokines. Adults whose parents lived apart and never spoke during their childhood were more than three times as likely to develop a cold when exposed to the upper respiratory virus than adults from intact families. Conversely, individuals whose parents were separated but communicated with each other showed no increase in risk compared with those from intact families. These differences persisted in analyses adjusted for potentially confounding variables (demographics, current socioeconomic status, body mass index, season, baseline immunity to the challenge virus, affectivity, and childhood socioeconomic status). Mediation analyses were consistent with the hypothesis that greater susceptibility to respiratory infectious illness among the offspring of noncommunicating parents was attributable to a greater local proinflammatory response to infection.

Gender Differences in the Benefits of an Influential Early Childhood Program
Jorge Luis García, James Heckman & Anna Ziff
NBER Working Paper, May 2017


This paper estimates gender differences in life-cycle impacts across multiple domains of an influential enriched early childhood program targeted toward disadvantaged children that was evaluated by the method of random assignment. We assess the impacts of the program on promoting or alleviating population differences in outcomes by gender. For many outcomes, boys benefit relatively more from high-quality center childcare programs compared to low-quality programs. For them, home care, even in disadvantaged environments, is more beneficial than lower-quality center childcare for many outcomes. This phenomenon is not found for girls. We investigate the sources of the gender differentials in impacts.

Teenage Motherhood and Sibling Outcomes
Jennifer Heissel
American Economic Review, May 2017, Pages 633-637


Using annual longitudinal data, I show that all children in families with teen childbearing are on a downward trajectory several years before pregnancy begins. Compared to students on similar trajectories from families without teenage childbearing, siblings of teen mothers have lower test scores, higher high school dropout, and higher juvenile justice system exposure following the birth. The change in test score outcomes occurs after the baby is born, indicating that the child's arrival affects performance, rather than some unobserved occurrence leading to both teen pregnancy and poor outcomes. The test scores for teen mothers drop in the year of pregnancy.

Father Absence and the Educational Gender Gap
Shelly Lundberg
University of California Working Paper, May 2017


The educational attainment of young women now exceeds that of young men in most of the developed world, and women account for about 60% of new four-year college graduates in the United States. Several studies have suggested that the increase in single-parent households may be contributing to the growing gender gap in education, as boys are more vulnerable to the negative effects of father absence and economic disadvantage than girls. Using data on recent cohorts of young men and women from the National Longitudinal Study of Adolescent to Adult Health (Add Health), I find evidence consistent with other studies that boys are relatively more likely to experience problems in school, including school suspensions, when their father is absent, but also that girls are relatively more likely to experience depression in adolescence, particularly in step-father families. By the time Add Health subjects are young adults, there is no evidence that father absence early in life is more strongly associated with lower rates of college graduation for men, compared to women, in either cross-sectional or family fixed-effect models.

Fathers’ Alcohol and Cannabis Use Disorder and Early Onset of Drug Use by Their Children
Kimberly Henry
Journal of Studies on Alcohol and Drugs, May 2017, Pages 458–462

Method: Prospective, longitudinal, and intergenerational data on 274 father–child dyads were used. Logistic regression models were estimated to assess the association between fathers’ lifetime incidence of an alcohol and cannabis use disorder and children’s onset of use of these same substances at or before age 15.

Results: The children of fathers who met the criteria for a lifetime cannabis use disorder were more likely to initiate use of alcohol (odds ratio = 6.71, 95% CI [1.92, 23.52]) and cannabis (odds ratio = 8.13, 95% CI [2.07, 31.95]) by age 15, when background covariates and presence of a lifetime alcohol use disorder were controlled for. No unique effect of fathers’ alcohol use disorder on children’s onset of alcohol and cannabis use was observed.

Conclusions: Fathers’ lifetime cannabis use disorder had a unique and robust association with children’s uptake of alcohol and cannabis by age 15. Future research is needed to identify the mediating mechanisms that link fathers’ disorder with children’s early onset.

Household chaos as a context for intergenerational transmission of executive functioning
Alexis Brieant et al.
Journal of Adolescence, July 2017, Pages 40–48


Executive functioning (EF) may be transmitted across generations such that strengths or deficiencies in parent EF are similarly manifested in the child. The present study examined the contributions of parent EF and impulsivity on adolescent EF, and investigated whether household chaos is an environmental moderator that alters these transmission processes. American adolescents (N = 167, 47% female, 13–14 years old at Time 1) completed behavioral measures of EF and reported household chaos at Time 1 and one year later at Time 2. Parents completed behavioral measures of EF and self-reported impulsivity at Time 1. Results indicated that lower parent EF at Time 1 predicted lower adolescent EF at Time 2 (controlling for adolescent EF and IQ at Time 1), but only in the context of high household chaos. Findings suggest that household chaos may be a risk factor that compounds influences of poor parent EF and compromises adolescent EF development.

Intelligence, income, and education as potential influences on a child’s home environment: A (maternal) sibling-comparison design
Alexandria Ree Hadd & Joseph Lee Rodgers
Developmental Psychology, July 2017, Pages 1286-1299


The quality of the home environment, as a predictor, is related to health, education, and emotion outcomes. However, factors influencing the quality of the home environment, as an outcome, have been understudied — particularly how children construct their own environments. Further, most previous research on family processes and outcomes has implemented between-family designs, which limit claims of causality. The present study uses kinship data from the National Longitudinal Survey of Youth to construct a maternal sibling-comparison design to investigate how maternal and child traits predict the quality of home environment. Using a standard between-family analysis, we first replicate previous research showing a relationship between maternal intelligence and the quality of the home environment. Then, we reevaluate the link between maternal intelligence and the home environment using differences between maternal sisters on several characteristics to explain differences between home environments for their children. Following, we evaluate whether child intelligence differences are related to home environment differences in the presence of maternal characteristics. Results are compared with those from the between-family analysis. Past causal interpretations are challenged by our findings, and the role of child intelligence in the construction of the home environment emerges as a critical contributor that increases in importance with development.

Advantageous developmental outcomes of advancing paternal age
Magdalena Janecka et al.
Translational Psychiatry, June 2017


Advanced paternal age (APA) at conception has been associated with negative outcomes in offspring, raising concerns about increasing age at fatherhood. Evidence from evolutionary and psychological research, however, suggests possible link between APA and a phenotypic advantage. We defined such advantage as educational success, which is positively associated with future socioeconomic status. We hypothesised that high IQ, strong focus on the subject of interest and little concern about ‘fitting in’ will be associated with such success. Although these traits are continuously distributed in the population, they cluster together in so-called ‘geeks’. We used these measures to compute a ‘geek index’ (GI), and showed it to be strongly predictive of future academic attainment, beyond the independent contribution of the individual traits. GI was associated with paternal age in male offspring only, and mediated the positive effects of APA on education outcomes, in a similar sexually dimorphic manner. The association between paternal age and GI was partly mediated by genetic factors not correlated with age at fatherhood, suggesting contribution of de novo factors to the ‘geeky’ phenotype. Our study sheds new light on the multifaceted nature of the APA effects and explores the intricate links between APA, autism and talent.

Numbers Assigned in the Vietnam-Era Selective Service Lotteries Influence the Military Service Decisions of Children Born to Draft-Eligible Men: A Research Note
Tim Johnson et al.
Armed Forces & Society, forthcoming


Previous research has reported correlations between the military service records of parents and their children. Those studies, however, have not determined whether a parent’s military service causally influences an offspring’s participation in the armed forces. To investigate the possibility of a causal relationship, we examined whether lottery numbers issued to draft-eligible men during the U.S. Vietnam-era Selective Service Lotteries influenced the military participation of those men’s children. Our study found higher rates of military participation among children born to fathers whose randomly assigned numbers were called for induction. Furthermore, we perform statistical analyses indicating that the influence of lottery numbers on the subsequent generation’s military participation operated through the military service of draft-eligible men as opposed to mechanisms unrelated to service such as “draft dodging.” These findings provide evidence of a causal link between the military service of parents and their children.

Jealousy and Attachment: Adaptations to Threat Posed by the Birth of a Sibling
Sybil Hart
Evolutionary Behavioral Sciences, forthcoming


This paper theorizes on the constructs of jealousy and infant-caregiver attachment by proposing a synthesis that bridges parent-offspring conflict theory (POCT; Trivers, 1974) with the evolutionary-ethological theory of attachment (Bowlby, 1969). Following Bowlby, we recognize attachment as an adaptation to threat to infant survival in ancestral settings. However, departing from his focus on environmental danger as the source of threat, we draw on Trivers’ understanding of siblings as competitors for parents’ scarce and finite resources, and propose that attachment was compelled by threat posed by the birth of a sibling. In support of this synthesis, we present evidence that illuminates infants’ need for exclusivity in the infant-maternal relationship, and elaborate on the origin of that need as a function of the benefits of exclusivity to infant survival. We also present evidence that infants’ defense against usurpation, jealousy protest, resembles attachment behavior, specifically separation protest, in terms of the specificity of the context in which it is presented, its direction and affective tone, the timing of its onset, and pattern of individual differences. The fact that both jealousy protest and separation protest occur at approximately 9 months of age, which is the juncture when a sibling’s birth is possible, suggests that both forms of protest were compelled by inevitable consequences of a sibling’s birth, namely, sibling competition for parental resources and mother-initiated separation. We argue that as a recurrent and universal event that presaged threat of both usurpation and separation, the birth of a sibling represents the ultimate foundation of attachment.

Establishment of Legal Paternity for Children of Unmarried American Women: Trade-Offs in Male Commitment to Paternal Investment
Kermyt Anderson
Human Nature, June 2017, Pages 168–200


The establishment of a legal father for children of unmarried parents reflects both high paternity confidence and male willingness to commit to paternal investment. Whether an unmarried man voluntarily acknowledges paternity after a child is born has important consequences for both the mother and child. This paper brings to bear a life history perspective on paternity establishment, noting that men face trade-offs between mating and parental effort and that women will adjust their investment in children based on expected male investment. I predict that paternity establishment will be more likely when the mother has high socioeconomic status, when maternal health is good, and when the child is male, low parity, or a singleton (versus multiple) birth. I further predict that establishment of paternity will be associated with increased maternal investment in offspring, resulting in healthier babies with higher birthweights who are more likely to be breastfed. These predictions are tested using data on 5.4 million births in the United States from 2009 through 2013. Overall the results are consistent with the hypothesis that the trade-offs men face between reproductive and parental investment influence whether men voluntarily acknowledge paternity when a child is born.

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