Biomedical subjects

Joseph Lee Rodgers

Publications and source records attributed to Joseph Lee Rodgers.

8 recordsLinked to original sources

PubMed2006

Testing descriptive hypotheses regarding sex differences in the development of conduct problems and delinquency.

Accurate descriptions of sex differences in the development of childhood conduct problems and adolescent delinquency will inform theories of their causes in fundamentally important ways. Using data on 4,572 offspring of a national sample of women, we tested descriptive hypotheses regarding sex differences. As predicted, the magnitude of sex differences varied with age, suggesting that multiple processes differentially influence levels of these behaviors in females and males across development. During childhood, boys scored lower on measures of cognitive ability and exhibited lower sociability and compliance and greater hyperactivity, oppositional behavior, and conduct problems. Most of these variables were associated with childhood conduct problems and adolescent delinquency equally in females and males, but maternal delinquency and early childhood sociability were correlated more strongly with childhood conduct problems in males and childhood compliance predicted adolescent delinquency more strongly in females. Both sexes exhibited both childhood-onset and adolescent-onset trajectories of delinquency. Although more males followed a childhood-onset trajectory, there were few sex differences in the early childhood risk correlates of either delinquency trajectory.

Adolescent↗

PubMed2006

Bio-social determinants of fertility.

This paper reviews several studies that investigated the potential role of genetic factors in determining fertility outcomes. Our review demonstrates convincingly that fertility contains genetic variance; that is, differences between humans in their genetic make-up affects their fertility outcomes and fertility-related behaviours. This finding is robust using both heritabilities and coefficients of genetic variation, and using both direct measures of fertility outcomes and also fertility precursors like fecundity, marriage, fertility expectations and attempts to get pregnant (proception). Moreover, genetic variance can change over short periods of time or across educational levels, specifically for females, and the relevance of genetic variance seems to increase during times of increasing reproductive choice.

Demography↗

PubMed2006

A multilevel approach to the relationship between birth order and intelligence.

Many studies show relationships between birth order and intelligence but use cross-sectional designs or manifest other threats to internal validity. Multilevel analyses with a control variable show that when these threats are removed, two major results emerge: (a) birth order has no significant influence on children's intelligence and (b) earlier reported birth order effects on intelligence are attributable to factors that vary between, not within, families. Analyses on 7- to 8 - and 13- to 14-year-old children from the National Longitudinal Survey of Youth support these conclusions. When hierarchical data structures, age variance of children, and within-family versus between-family variance sources are taken into account, previous research is seen in a new light.

Adolescent↗

PubMed2005

Reformulating and simplifying the DF analysis model.

DeFries-Fulker (DF) Analysis for unselected populations is reformulated as a no-intercept model with centered variables and only two independent variables. The reformulation serves three purposes. First, the original formulation implicitly estimated two different values for c2 and two values for h2. The new formulation resolves this ambiguity. Second, because the original formulation estimated h2 with the coefficient from a regression-interaction term, whether to center the interaction variables was unclear. The new formulation explicitly resolves this issue. Finally, the new formulation estimates fewer parameters, and therefore improves estimation efficiency and statistical power.

Fertility↗

PubMed2005

Did fertility go up after the Oklahoma City bombing? An analysis of births in metropolitan counties in Oklahoma, 1990-1999.

Political and sociocultural events (e.g., Brown v. Board of Education in 1954 and the German reunification in 1989) and natural disasters (e.g., Hurricane Hugo in 1989) can affect fertility. In our research, we addressed the question of whether the Oklahoma City bombing in April 1995, a man-made disaster, influenced fertility patterns in Oklahoma. We defined three theoretical orientations--replacement theory, community influence theory, and terror management theory--that motivate a general expectation of birth increases, with different predictions emerging from time and geographic considerations. We used two different empirical methodologies. First, we fitted dummy-variable regression models to monthly birth data from 1990 to 1999 in metropolitan counties. We used birth counts to frame the problem and general fertility rates to address the problem formally. These analyses were organized within two design structures: a control-group interrupted time-series design and a difference-in-differences design. In these analyses, Oklahoma County showed an interpretable, consistent, and significant increase in births. Second, we used graphical smoothing models to display these effects visually. In combination, these methods provide compelling support for a fertility response to the Oklahoma City bombing. Certain parts of each theory helped us organize and understand the pattern of results.

Adolescent↗

PubMed2002

Theory development should begin (but not end) with good empirical fits: a comment on Roberts and Pashler (2000).

S. Roberts and H. Pashler (2000) argued against using goodness of fit as evidence to support theories. The authors agree with their suggestions for how to go beyond good fits but disagree with their starting point. In this comment, the authors argue that good fits are part and parcel of theory development, that they are part and parcel of the processes suggested by S. Roberts and H. Pashler, and that they must be the starting point (though far from the ending point) in theoretical development. The authors discuss historical examples of scientific theory development, recent examples of psychological theory development, and development of a particular theory (social contagion theory; J. L. Rodgers & D. C. Rowe, 1993) that S. Roberts and H. Pashler criticized.

Decision Support Techniques↗

PubMedDate not supplied

Between nurture and nature: the shifting determinants of female fertility in Danish twin cohorts.

Behaviors related to fertility constitute primary candidates for investigating the relevance of evolutionary influences and biological dispositions on contemporary human behaviors. Using female Danish twin cohorts born 1870-1968, we document important transformations in the relative contributions of "nurture" and "nature" to within-cohort variations in early and complete fertility, and we point toward a systematic relation between the socioeconomic context of cohorts and the relevance of genetic and shared environmental factors. This transformation is most striking for early fertility where genetic factors strengthen over time and are consistent with up to 50 percent of the variation in early fertility in most recent cohorts. Understanding this emerging relevance of genetic factors is of central importance because early fertility constitutes an important determinant of complete fertility levels in low-fertility societies, and because teenage motherhood and early childbearing are often associated with negative life-cycle consequences. Moreover, our results emphasize the need for socially and contextually informed analyses of nature and nurture that allow both factors to influence human reproductive behavior over time.

Adult↗

PubMedDate not supplied

Did births decline in the United States after the enactment of no-fault divorce law?

Previous research has demonstrated that U.S. no-fault divorce laws implemented between 1953 and 1987 resulted in more divorces in some states than would have occurred otherwise. In other states, divorce patterns appeared to follow prevailing trends even after implementation of no-fault divorce legislation. A more distal question is whether implementation of no-fault divorce laws had an effect on birth rates. We analyzed state-level birth data from all 50 states to assess the birth response to the enactment of no-fault divorce law in each state. Results suggested that birth rates decreased significantly two to four years following the enactment of no-fault divorce law for the group of 34 states whose divorce rates responded to no-fault divorce legislation. As predicted, among the 16 states whose divorce rates did not respond to no-fault divorce legislation, the enactment of no-fault divorce law had a small and nonsignificant positive influence on birth rates. Generally, the group of 34 states had lower post no-fault birth rates than the group of 16 states.

Birth Rate↗