The Decline in Adult Activities Among U.S. Adolescents, 1976-2016
Jean Twenge & Heejung Park
Child Development, forthcoming
The social and historical contexts may influence the speed of development. In seven large, nationally representative surveys of U.S. adolescents 1976-2016 (N = 8.44 million, ages 13-19), fewer adolescents in recent years engaged in adult activities such as having sex, dating, drinking alcohol, working for pay, going out without their parents, and driving, suggesting a slow life strategy. Adult activities were less common when median income, life expectancy, college enrollment, and age at first birth were higher and family size and pathogen prevalence were lower, consistent with life history theory. The trends are unlikely to be due to homework and extracurricular time, which stayed steady or declined, and may or may not be linked to increased Internet use.
It Runs in the Family: A Study of Political Candidacy Among Swedish Adoptees
Sven Oskarsson, Christopher Dawes & Karl-Oskar Lindgren
Political Behavior, forthcoming
What motivates citizens to run for office? Recent work has shown that early life parental socialization is strongly associated with a desire to run for office. However, parents not only shape their children's political environment, they also pass along their genes to those same children. A growing area of research has shown that individual differences in a wide range of political behaviors and attitudes are linked to genetic differences. As a result, genetic factors may confound the observed political similarities among parents and their children. This study analyzes Swedish register data containing information on all nominated and elected candidates in the ten parliamentary, county council, and municipal elections from 1982 to 2014 for a large sample of adoptees and their adoptive and biological parents. By studying the similarity in political ambition within both adoptive and biological families, our research design allows us to disentangle so-called "pre-birth" factors, such as genes and pre-natal environment, and "post-birth" factors like parental socialization. We find that the likelihood of standing as a political candidate is twice as high if one's parent has been a candidate. We also find that the effects of pre-birth and post-birth factors are approximately equal in size. In addition, we test a number of potential pre- and post-birth transmission mechanisms. First, disconfirming our expectations, the pre-birth effects do not seem to be mediated by cognitive ability or leadership skills. Second, consistent with a role modeling mechanism, we find evidence of a strong transmission in candidacy status between rearing mothers and their daughters.
Dramatic pretend play games uniquely improve emotional control in young children
Thalia Goldstein & Matthew Lerner
Developmental Science, forthcoming
Pretense is a naturally occurring, apparently universal activity for typically developing children. Yet its function and effects remain unclear. One theorized possibility is that pretense activities, such as dramatic pretend play games, are a possible causal path to improve children's emotional development. Social and emotional skills, particularly emotional control, are critically important for social development, as well as academic performance and later life success. However, the study of such approaches has been criticized for potential bias and lack of rigor, precluding the ability to make strong causal claims. We conducted a randomized, component control (dismantling) trial of dramatic pretend play games with a low-SES group of 4-year-old children (N = 97) to test whether such practice yields generalized improvements in multiple social and emotional outcomes. We found specific effects of dramatic play games only on emotional self-control. Results suggest that dramatic pretend play games involving physicalizing emotional states and traits, pretending to be animals and human characters, and engaging in pretend scenarios in a small group may improve children's emotional control. These findings have implications for the function of pretense and design of interventions to improve emotional control in typical and atypical populations. Further, they provide support for the unique role of dramatic pretend play games for young children, particularly those from low-income backgrounds.
Using monozygotic twin differences to examine the relationship between parental affection and personality: A life history account
Curtis Dunkel, Joseph Nedelec & Dimitri van der Linden Evolution and
Human Behavior, forthcoming
The relationship between maternal and paternal affection, reported in adulthood, and personality was examined using a genetically sensitive research design comparing differences between monozygotic twins. Using life history theory as a framework, it was predicted that differences in maternal and paternal affection would be predictive of differences in personality such that the twin reporting greater maternal and paternal affection would also report a personality profile reflective of a slow life history strategy. Specifically, it was predicted that the twin that reported greater maternal and paternal affection would also score high on the meta-traits of plasticity, stability, and the general factor of personality (GFP). The results supported the hypotheses, with most variance accounted for by the GFP. Additional results suggest that differences in paternal affection exhibit a stronger effect and that stability and plasticity may provide unique information about the association between differences in parental affection and differences in personality. Attachment and parental investment theories offer possible explanations for the findings, although alternative explanations are also proffered. It may also be beneficial for future research using a monozygotic twin difference approach to utilize biometric measures of life history strategy.
Genetic and environmental contributions to age at menarche: Interactive effects of father absence and LIN28B
Gabriel Schlomer & Hyun-Jin Cho
Evolution and Human Behavior, November 2017, Pages 761-769
Substantial research and theory over a number of years have linked father absence to earlier age at menarche (AAM). More recent work has centered on explaining the relative genetic and environmental contributions to this correlation. The purpose of the current study was to evaluate the combined effects of father absence and variation in the LIN28B gene on AAM. A sample of 300 women (age 18-25) successfully genotyped for two LIN28B single nucleotide polymorphisms (SNPs; rs364663 and rs314273) were used to test gene-environment interaction models. Results for both SNPs were consistent with the hypothesis that father absence would attenuate later AAM associated with LIN28B. Genetic index analysis of combined LIN28B SNPs showed that girls with at least one copy of the T/T genotype had later AAM if they were father present. Study strengths and the implications of GxE research for life history models are discussed.
Paternal grandmothers benefit the most from expressing affection to grandchildren: An extension of evolutionary and sociological research
Quinten Bernhold & Howard Giles
Journal of Social and Personal Relationships, forthcoming
This study explored how type of grandparent is related to grandparents' affectionate communication and grandchildren's relational closeness to grandparents. We predicted that grandchildren would be closest to and receive the most affection from maternal grandmothers, followed by maternal grandfathers, paternal grandmothers, and paternal grandfathers. We also hypothesized that type of grandparent would moderate the associations between affection and closeness. Using a convenience sample of grandchildren (n = 281), we found that grandchildren were closer to maternal grandparents rather than paternal grandparents. Grandchildren reported receiving more memories and humor from their paternal grandfathers rather than their maternal grandmothers. Type of grandparent moderated the associations between the love and esteem received from grandparents and closeness as well as the associations between the physical tokens of affection received from grandparents and closeness such that associations were amplified for paternal grandmothers. Findings are discussed in terms of their contributions to evolutionary and sociological research.
Sibling gender and wage differences
Neel Rao & Twisha Chatterjee
Applied Economics, forthcoming
Family influences on economic performance are investigated. In particular, sibship sex composition is related to hourly wages using data from the National Longitudinal Survey of Youth 1979. The wages of men are increasing in the proportion of siblings who are brothers, but the wages of women are insensitive to sibling gender. Nonwage outcomes are generally unaffected. Contrasts by age structure and demographic group are also presented. The analysis addresses econometric challenges like the endogeneity of fertility and selection into the workforce. In addition, mechanisms such as labour market interactions, human capital investment and role model effects are documented. A questionnaire on job search indicates a same-gender bias in the use of brothers and sisters in obtaining employment. Developmental and psychological assessments suggest that brothers may be associated with worse childhood home environments and more traditional family attitudes among women. The findings are policy relevant and contribute to an understanding of gender differences and earnings inequality.