Joe Rodgers

• University of Oklahoma

Previous work using U.S. data has identified generational shifts, reflected in inter-cohort changes, in the incidence and prevalence of diseases in older ages. This study extends previous findings to England by examining similar results in memory complaints, heart conditions, stroke, diabetes, lung disease, and cancer using data from the English Lo...

To contribute to our understanding of cohort differences and the Flynn effect in the cognitive decline among older Americans, this study aims to compare rates of cognitive decline between two birth cohorts within a study of older Americans and to examine the importance of medical and demographic confounders. Analyses used data from the National Hea...

Objective: Using a large longitudinal sample of adults from the Midlife in the United States (MIDUS) study, the present study extended a recently developed hierarchical model to determine how best to longitudinally model cumulative stress, and to determine whether the rate of change in stress or the level of cumulative stress over time are stronger...

Objective This paper models cognitive aging, across mid and late life, and estimates birth cohort and sex differences in both initial-levels and aging trajectories over time in a sample with multiple cohorts and a wide span of ages. Methods The data used in this study came from the first nine waves of the English Longitudinal Study of Ageing (ELSA...

The Flynn effect refers to increases over time in measured (particularly fluid) intelligence of approximately 3 IQ points per decade. We define the Flynn effect at the family level, using longitudinal data and two new family-level cohort definitions. Multilevel growth curve analyses of the National Longitudinal Survey of Youth 1979 data showed that...

To contribute to our understanding of cohort differences and the Flynn Effect in cognitive declines, this study aims to: 1) describe and compare cognitive decline trends of two nationally representative American older cohorts; 2) investigate significant determinants of cognitive declines and the cohort differences. The analysis used data from the N...

The Flynn effect (Flynn, 1984; 1987) refers to increases in cognitive performance, for later-born cohorts. It has been documented globally, occurring for more than a century. In a meta-analysis, Pietschnig and Voracek (2015) noted that the effect may be even stronger in adults than in children, though little research has addressed this topic (or it...

Declines in cognitive functioning with increased age, on average and individually, is well documented and demonstrated to be related to genetics and a variety of life course risk factors, many of which are modifiable. Related to population cognitive aging is the phenomenon of the Flynn effect, the finding of increasing cognitive test scores across...

Researchers have reported that later-born cohorts often have higher scores on cognitive tests, potentially indicating that some of the differences normally attributed to cognitive aging may reflect developmental differences. The present study examined the hypotheses that social factors at birth and in early adolescence might partially explain birth...

Objective: Types and subtypes of peer victimization (PV) behaviors have long been identified among school-age children and adolescents. The present study aims to establish such typologies for older adolescents and young adults who are still in school given the fact that colleges and universities are increasingly concerned about such behaviors among...

This study evaluated changes over time in the quality of children’s home environment, using the Home Observation Measurement of the Environment (HOME). Longitudinal increases in HOME scores were predicted by both theory and past empirical results. Analysis of the National Longitudinal Survey of Youth Children data (N = 5715, aged 0–14) suggested th...

Epidemic Models of the Onset of Social Activities (EMOSA) describe behaviors that spread through social networks. Two social influence methods are represented, social contagion (one‐to‐one spread) and general diffusion (spread through cultural channels). Past models explain problem behaviors—smoking, drinking, sexuality, and delinquency. We provide...

In light of the "replication crisis," some advocate for stricter standards and greater transparency in research methods. These efforts push toward a data analysis approach called "confirmatory data analysis" (CDA; see Wagenmakers et al., 2012). However, some (e.g., Baumeister, 2016; Goldin-Meadow, 2016) suggest that emphasizing CDA may restrict cre...

Background Grip strength is a popular and valuable measure in studies of physical functional capabilities in old-age. The influence of historical trends and differential period-specific exposures can complicate the interpretation of biomarkers of aging and health and requires careful analysis and interpretation of ageing, birth cohort, and period e...

Many behavior genetics models follow the same general structure. We describe this general structure and analytically derive simple criteria for its identification. In particular, we find that variance components can be uniquely estimated whenever the relatedness matrices that define the components are linearly independent (i.e., not confounded). Th...

Studies have reported that the age‐adjusted incidence of cognitive impairment and dementia have decreased over the past two decades. Aging is the predominant risk factor for Alzheimer's disease and related dementias and for neurocognitive decline. However, aging alone cannot explain changes in the overall age‐adjusted incidence of dementia. The obj...

Final Paper Version of my Dissertation

In behavior genetics, like many fields, researchers must decide whether their models adequately explain their data – whether their models “fit” at some satisfactory level. Well-fitting models are compelling, whereas poorly-fitting models are not (Rodgers & Rowe, 2002). Oftentimes, researchers evaluate model fit by employing “universal” rules of thu...

The Flynn Effect (FE; Flynn, 1984, Flynn, 1987) is the decades-long increase in measured mean IQ of approximately 1/3 point per year, observed in industrialized nations over the course of at least a century. An obvious and practical implication of the FE is that the FE can cause test norm obsolescence. If norms from 1970 were used today, the averag...

Colleges and universities are increasingly concerned about respect for diversity and tolerance of individual differences on their campuses. Nevertheless, no comprehensive measure of peer victimization has been developed and validated for use with college student populations. The Peer Victimization in College Survey (PVIC) is the first such measure....

The univariate bootstrap is a relatively recently developed version of the bootstrap (Lee and Rodgers in Psychol Methods 3(1): 91, 1998). DeFries–Fulker (DF) analysis is a regression model used to estimate parameters in behavioral genetic models (DeFries and Fulker in Behav Genet 15(5): 467–473, 1985). It is appealing for its simplicity; however, i...

Wayne Velicer is remembered for a mind where mathematical concepts and calculations intrigued him, behavioral science beckoned him, and people fascinated him. Born in Green Bay, Wisconsin on March 4, 1944, he was raised on a farm, although early influences extended far beyond that beginning. His Mathematics BS and Psychology minor at Wisconsin Stat...

Longitudinal studies have documented improvements in parents’ life satisfaction due to childbearing, followed by postpartum adaptation back to baseline. However, the details underlying this process remain largely unexplored. Based on past literature, set-point theory, and results from an exploratory sample, we investigated empirically how first chi...

Longitudinal studies have documented improvements in parents’ life satisfaction due to childbearing, followed by postpartum adaptation back to baseline. However, the details underlying this process remain largely unexplored. Based on past literature, set-point theory, and results from an exploratory sample, we investigated empirically how first chi...

In light of the “replication crisis,” some (e.g., Nelson, Simmons, & Simonsohn, 2018) advocate for greater policing and transparency in research methods. Others (Baumeister, 2016; Finkel, Eastwick, & Reis, 2017; Goldin-meadow, 2016; Levenson, 2017) argue against rigid requirements that may inadvertently restrict discovery. We embrace both positions...

Degrees of freedom is a critical core concept within the field of statistics. Virtually every introductory statistics class treats the topic, though textbooks and the statistical literature show mostly superficial treatment, weak pedagogy, and substantial confusion. Fisher first defined degrees of freedom in 1915, and Walker provided technical trea...

In 1918, Fisher suggested that his research team had consistently found inflated cousin correlations. He also commented that because a cousin sample with minimal selection bias was not available the cause of the inflation could not be addressed, leaving this inflation as a challenge still to be solved. In the National Longitudinal Survey of Youth (...

The consistent relationship between socioeconomic status (SES) and health has been widely covered in the media and scientific journals, which typically argue that physical-health inequalities are caused by material disadvantage directly or indirectly (e.g., chronic environmental-stress, health care resources, etc.). Such explanations do not explain...

Psychology advances knowledge by testing statistical hypotheses using empirical observations and data. The expectation is that most statistically significant findings can be replicated in new data and in new laboratories, but in practice many findings have replicated less often than expected, leading to claims of a replication crisis. We review rec...

Psychological science is in the midst of what has been referred to as a “replication crisis.” The realization that many individual findings do not replicate in new studies has led to questioning the scientific method and the integrity of psychological science. We review the history of the replication crisis, and its positive and negative effects. M...

We examine some key errors that influence the validity of scientific inquiry in the social and behavioral sciences, emphasizing the need for researchers to be attuned to the varied sources of error. We discuss error beyond simple inferential processes inherent in null hypotheses testing, for example. and broaden the scope of influences in the model...

This paper introduces an extension of cluster mean centering (also called group mean centering) for multilevel models, which we call “double decomposition (DD).” This centering method separates between-level variance, as in cluster mean centering, but also decomposes within-level variance of the same variable. This process retains the benefits of c...

Halpern et al. (2000) published a study based on early Add Health data with the provocative title “Smart Teens Don’t Have Sex (or Kiss Much Either).” Several following papers reported the same result, a positive correlation between the intelligence of adolescent girls and age at first intercourse (AFI). However, the causal mechanism has not been ca...

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 implement...

Halpern et al. (2000) published a study based on early Add Health data with the provocative title “Smart Teens Don’t Have Sex (or Kiss Much Either).” Several following papers reported the same result, a positive correlation between the intelligence of adolescent girls and age at first intercourse (AFI). However, the causal mechanism has not been ca...

The National Longitudinal Survey of Youth datasets (NLSY79; NLSY-Children/Young Adults; NLSY97) have extensive family pedigree information contained within them. These data sources are based on probability sampling, a longitudinal design, and a cross-generational and within-family data structure, with hundreds of phenotypes relevant to behavior gen...

The Bayesian-frequentist debate typically portrays these statistical perspectives as opposing views. However, both Bayesian and frequentist statisticians have expanded their epistemological basis away from a singular focus on the null hypothesis, to a broader perspective involving the development and comparison of competing statistical/mathematical...

This essay, written by the guest editor, is an introduction to a special issue of the Journal of Intelligence devoted to methodological issues associated with the Flynn Effect. The essay evaluates past Flynn Effect research in terms of exploratory versus confirmatory efforts. Future research is also cast within this same framework. Finally, the fou...

Better understanding risk factors for the development of adolescent emotional and behavioral problems can help with intervention and prevention efforts. Previous studies have found that an early menarcheal age predicts several adolescent problems, including depressive symptoms, delinquency, and early age at first intercourse. Few studies, neverthel...

Many data structures, particularly time series data, are naturally seasonal, cyclical, or otherwise circular. Past graphical methods for time series have focused on linear plots. In this article, we move graphical analysis onto the circle. We focus on 2 particular methods, one old and one new. Rose diagrams are circular histograms and can be produc...

A powerful longitudinal data source, the National Longitudinal Survey of Youth Children data, allows measurement of behavior problems (BP) within a developmental perspective linking them to menarcheal timing (MT). In a preliminary analysis, we evaluate the bivariate relationships between BP measured at different developmental periods and the timing...

I reinterpret a forty-year-old finding by Belmont and Marolla (1973), who believed their Dutch IQ patterns were caused by within-family processes related to birth order. However, their inferred relation was almost certainly caused by differences between families — in parental IQ, maternal education, and/or dozens of other processes. I show that the...

Much research has been directed at the validity of fit indices in Path Analysis and Structural Equation Modeling (e.g., Browne, MacCallum, Kim, Andersen, & Glaser, 2002; Heene, Hilbert, Draxler, Ziegler, & Bühner, 2011; Hu & Bentler, 1999; Marsh, Hau, & Wen, 2004). Recent developments (e.g., Preacher, 2006; Roberts & Pashler, 2000, 2002) have encou...

Frequently a researcher is interested in a theoretical distribution or characteristics of that distribution, such as its mean, standard deviation, or 2.5 and 97.5 percentiles. One hundred or even 50 years ago, we were restricted practically by computing limitations to theoretical distributions that are described by an explicit equation, such as the...

A quasi-experimental comparison of cousins differentially exposed to levels of neighborhood disadvantage (ND) was used with extensive measured covariates to test the hypothesis that neighborhood risk has independent effects on youth conduct problems (CPs). Multilevel analyses were based on mother-rated ND and both mother-reported CPs across 4-13 ye...

We propose, develop, and evaluate the black ink-red ink (BIRI) method of testing. This approach uses two different methods within the same test administration setting, one that matches recognition learning and the other that matches recall learning. Students purposively define their own tradeoff between the two approaches. Evaluation of the method...

The attack on the World Trade Center (WTC) on September 11, 2001, was an act of terrorism that had many potential influences on the city and state, including influences on families. We analyzed divorce data from 1991 to 2005 for all 62 New York counties to assess divorce response to the attack on the WTC. The results suggested that there were lower...

Nonmaternal care of infant children is increasingly common, but there is disagreement as to whether it is harmful for children. Using data from 9,185 children (5 years and older) who participated in the Children of the National Longitudinal Survey of Youth, the current study compared 2 groups: those for whom nonmaternal care was initiated in the fi...

The authors review key features in the development of a successful PhD program delivered at a distance, including students, cohorts, teaching, curriculum, administrative structure, and current and future challenges.

Some of Robinson & Levin's critique of Rodgers (2010) is cogent, helpful, and insightful - although limiting. Recent methodology has advanced through the development of structural equation modeling, multi-level modeling, missing data methods, hierarchical linear modeling, categorical data analysis, as well as the development of many dedicated and s...

Although the Flynn Effect has been studied widely across cultural, geographic, and intellectual domains, and many explanatory theories have been proposed, little past research attention has been paid to subgroup differences. Rodgers and Wänström (2007) identified an aggregate-level Flynn Effect (FE) at each age between 5 and 13 in the Children of t...

In spite of long-held beliefs that traits related to reproductive success tend to become fixed by evolution with little or no genetic variation, there is now considerable evidence that the natural variation of fertility within populations is genetically influenced and that a portion of that influence is related to the motivational precursors to fer...

We examine how the motivational sequence that leads to childbearing predicts fertility outcomes across reproductive careers. Using a motivational traits-desires-intentions theoretical framework, we test a structural equation model using prospective male and female data from the National Longitudinal Survey of Youth. Specifically, we take motivation...

A quiet methodological revolution, a modeling revolution, has occurred over the past several decades, almost without discussion. In contrast, the 20th century ended with contentious argument over the utility of null hypothesis significance testing (NHST). The NHST controversy may have been at least partially irrelevant, because in certain ways the...

It is necessary to determine if causal influences on developing antisocial behavior change with age to guide both research and theory on its origins. The extent to which the same genetic factors influence antisocial behavior across 4-17 years of age was estimated using 2,482 sibling pairs of varying genetic relatedness. Assessments of antisocial be...

Children raised without a biological father in the household have earlier average ages of first sexual intercourse than children raised in father-present households. Competing theoretical perspectives have attributed this either to effects of father absence on socialization and physical maturation or to nonrandom selection of children predisposed f...

Resampling is a statistical approach that relies on empirical analysis, based on the observed data, instead of asymptotic and parametric theory. The goal of resampling is to make an inferential decision, which is the same goal as that of a parametric statistical test such as the conventional t or ANOVA. The difference is in how the goal is achieved...

Recent studies suggest that the association between maternal age at childbearing (MAC) and children's disruptive behaviors is the result of family factors that are confounded with both variables, rather than a casual effect of environmental factors specifically related to MAC. These studies, however, relied on restricted samples and did not use the...

Theoretical models concerning how neighborhood contexts adversely influence juvenile antisocial behavior frequently focus on urban neighborhoods; however, previous studies comparing urban and rural areas on the prevalence of youth antisocial behavior have yielded mixed results. The current study uses longitudinal data on the offspring of a national...

Inattentive-hyperactive and oppositional behavior have been hypothesized to be developmental precursors to conduct problems. We tested these hypotheses using a longitudinal sample of 6,466 offspring of women selected from nationally representative US households. Conduct problems across 8-13 years were robustly predicted by conduct problems at 4-7 y...

The study presents a quasi-experimental analysis of data on 9,194 offspring (ages 4-11 years old) of women from a nationally representative U.S. sample of households to test the causal hypotheses about the association between family income and childhood conduct problems (CPs). Comparison of unrelated individuals in the sample indicated a robust inv...

Using National Longitudinal Survey of Youth (NLSY) fertility variables, we introduce and illustrate a new genetically-informative design. First, we develop a kinship linking algorithm, using the NLSY79 and the NLSY-Children data to link mothers to daughters and aunts to nieces. Then we construct mother–daughter correlations to compare to aunt–niece...

Recent studies suggest that most of what parents know about their adolescent offspring's whereabouts and companions is the result of youth disclosure, rather than information gained through active parental monitoring. This raises the possibility that parental knowledge is spuriously correlated with youth delinquency solely because the most delinque...

Predictive associations between parenting and temperament during the first year of life and child conduct problems were assessed longitudinally in 1,863 offspring of a representative sample of women. Maternal ratings of infant fussiness, activity level, predictability, and positive affect each independently predicted maternal ratings of conduct pro...

Purcell (Twin Res 5:554-571, 2002) proposed a bivariate biometric model for testing and quantifying the interaction between latent genetic influences and measured environments in the presence of gene-environment correlation. Purcell's model extends the Cholesky model to include gene-environment interaction. We examine a number of closely related al...

The authors study education and cognitive ability as predictors of female age at first birth (AFB), using monozygotic and dizygotic female twin pairs from the Middle-Aged Danish Twin survey. Using mediated regression, they replicate findings linking education (and not cognitive ability) to AFB. But in a behavior genetic model, both relationships ar...

Previous studies have documented that smoking during pregnancy (SDP) is associated with offspring externalizing problems, even when measured covariates were used to control for possible confounds. However, the association may be because of nonmeasured environmental and genetic factors that increase risk for offspring externalizing problems. The cur...

IntroductionDefinitions: Why Is This Chapter Difficult to Frame?Theoretical FrameworkMethodology Used in This ReviewBehavior Genetic Research on Adolescence: The Social/Behavioral EcologyBehavior Genetic Research on Adolescence: The Biological/Hormonal EcologySummary Statements and Conclusion