Joseph A. Schwartz

Psychopathic Personality Traits, Genetic Risk, and Gene-Environment Correlations:

There is a great deal of evidence indicating that psychopathy and psychopathic traits represent some of the strongest correlates to serious violent criminal behavior. As a result, there has been a recent surge of behavioral genetic studies examining the genetic and environmental factors that may be related to the development of psychopathy. The current study extends this line of research by analyzing a sample of kinship pairs from the National Longitudinal Study of Adolescent Health to estimate the extent to which genetic factors relate to measures of psychopathic personality traits created from the five factor model. Moreover, the authors also test for a series of gene—environment correlations between genetic risk for psychopathic personality traits and measures of parental negativity. The results of the analyses revealed that genetic factors explained between .37 and .44 of the variance in measures of psychopathy. Additional statistical models indicated the presence of gene—environment correlations between parental negativity and genetic risk for psychopathic personality traits.

MATHEMATICAL PROOF IS NOT MINUTIAE AND IRREDUCIBLE COMPLEXITY IS NOT A THEORY: A FINAL RESPONSE TO BURT AND SIMONS AND A CALL TO CRIMINOLOGISTS†

KEYWORDS: biosocial, assumptions, twinsIn their initial article, Burt and Simons (2014) laid out a range of specific criticismsof twin-based research. They argued that violations of the statistical assumptions thatunderpin this line of work result in upwardly biased estimates of heritability and down-wardlybiasedestimatesofenvironmentaleffects.AccordingtoBurtandSimons,thefind-ingsgeneratedfrombehavioralgeneticapproachesare“biologicallynonsensical”andare“misguided.” Indeed, Burt and Simons stated, without qualification, that an entire classof statistical models used to analyze twin data are “seriously flawed.” Because behavioralgenetic designs suffer from “fatal flaws,” they argued, twin-based research designs andtheir associated statistical methods should be put to an “end in criminology.”We examined their assertions carefully. We found that Burt and Simons (2014) cherry-picked the studies they cited in support of their position regarding the biasing impact ofthe equal environments assumption (EEA), something they openly admit in the onlinesupporting information of their rejoinder (Burt and Simons, 2015, this issue). Specifically,theystate,“wefocusedonarticlesthatshowedthattheEEAisnotavalidassumption”tosupport their claim that heritability estimates from behavioral genetic studies are chron-ically overestimated as a result of violations of this assumption. In fact, they relied pri-marily on a single source (Joseph, 1998, 2004, 2006, 2010) for their critique. Notably, wefound that they failed to cite the vast majority of the more than 60 studies that tested forviolations of the EEA—a body of work that is inconsistent with their claims.

Examining the effects of dopamine genes on verbal IQ within and between families

Although research findings have revealed that both genetic and environmental factors contribute to variation in IQ at the individual level, no studies have examined how genetic differences contribute to differences in IQ within and between families. The current study uses data drawn from the National Longitudinal Study of Adolescent Health (Add Health) to examine the potential role genetic factors play in shaping differences in IQ scores within and between families. The results revealed that while genetic variation between family members did not significantly predict differences in IQ scores, family-level dopaminergic risk scores did significantly predict differences in family-level IQ. The implications of the results are elaborated upon, and suggestions for future research are discussed.

Serious Fighting-Related Injuries Produce a Significant Reduction in Intelligence

PURPOSEnFighting-related injuries are common among adolescents within the United States, but how such injuries relate to subsequent cognitive functioning remains unclear. In particular, the long-term effect of fighting-related injuries suffered during important developmental periods, such as adolescence, on subsequent cognitive functioning has been overlooked by previous studies. The purpose of this study is to examine the association between sustaining serious fighting-related injuries and changes in verbal intelligence (IQ) over a 5- to 6-year time period.nnnMETHODSnLongitudinal multivariate statistical models were used to analyze data from the National Longitudinal Study of Adolescent Health collected between 1994 and 2002 and analyzed inxa02013.nnnRESULTSnEven a single fighting-related injury resulted in a significant reduction in IQ over time even after controlling for age, race, sex, and changes in socioeconomic status (SES) over the study period. Additionally, females experienced a significantly greater reduction in IQ from each fighting-related injury than males.nnnCONCLUSIONSnFighting-related injuries have a significant impact on subsequent cognitive functioning and intelligence. The implications for future policies and research are discussed in more detail.

Head Injuries and Changes in Delinquency from Adolescence to Emerging Adulthood: The Importance of Self-control as a Mediating Influence

Objectives: The current study examines whether head injuries suffered earlier in the life course are associated with subsequent changes in self-control and delinquency. Methods: Latent growth curve models and path analysis are used to analyze the developmental trajectories of self-control and delinquency as well as the potential associations between head injury, self-control, and delinquency among a sample of youth offenders from the pathways to desistance study. Results: The results revealed significant associations between head injuries and short-term changes in self-control and subsequent increases in aggressive delinquency. Indirect pathway models revealed that lower levels of self-control significantly mediated the association between head injuries and starting levels in aggressive delinquency. The association between head injuries and changes in aggressive delinquency was also significantly mediated by self-control, but the association was negative, indicating that youth who previously suffered head injuries desisted from aggressive delinquency at a slightly faster rate than their noninjured peers. Additional analyses revealed that, despite accelerated rates of decline, injured youth engaged in significantly higher levels of aggressive delinquency throughout the entire observation period. Conclusion: Head injuries represent one environmental factor that may influence delinquent behaviors through their influence on biological and developmental processes.

Exploring whether genetic differences between siblings explain sibling differences in criminal justice outcomes

Research has revealed that despite many similarities, siblings raised within the same household have also been found to be markedly different from one another. Behavioral differences between siblings have been primarily attributed to differential exposure to a wide variety of environmental influences. The potential role that between-sibling genetic differences play in the development of behavioral differences has been overlooked in the extant literature. The current study examines the association between differences in three dopaminergic polymorphisms (DAT1, DRD2, and DRD4) and differences in arrest, incarceration, and multiple arrests between siblings. Between-sibling difference scores were estimated for each examined polymorphism and each criminal justice outcome measure (along with all controls). Ordinary least squares (OLS) regression models were estimated to examine the potential association between genetic differences between siblings and differences in experiences within the criminal justice system. Models were estimated for the full sample and then for the same-sex male and female subsamples separately. The results provide preliminary evidence that between-sibling differences in some of the examined dopaminergic polymorphisms are associated with differences in contact with the criminal justice system. Findings are discussed in more detail and suggestions for future research are also provided.

Genetic Risks and ADHD Symptomatology: Exploring the Effects of Parental Antisocial Behaviors in an Adoption-Based Study

A great deal of research has examined the etiology of attention-deficit/hyperactivity disorder (ADHD) and ADHD symptomatologies. Genetic factors are consistently shown to explain a significant proportion of variance in measures of ADHD. The current study adds to this body of research by examining whether genetic liabilities for criminality and alcoholism have effects on the development of ADHD symptomatologies. Analyses based on a sample of adoptees drawn from the National Longitudinal Study of Adolescent Health (Add Health) revealed that ADHD symptomatologies were elevated among adoptees who had biological mothers and fathers who had been arrested or who were alcoholics. These results suggest that part of the covariation between ADHD and antisocial behaviors may be the result of genetic factors that have general effects across a range of maladaptive outcomes.

Evolutionary Behavioral Genetics of Violent Crime

The goal of this chapter is to provide an overview of the existing literature pertaining to evolutionary behavioral genetics and violent criminal behaviors. In doing so, we provide an introduction to the methodologies that are used to estimate the heritability of violent crime, and we review studies that have estimated the heritability of violent crime. We then offer some background information related to molecular genetics and also examine research that has attempted to isolate the specific genetic polymorphisms that might relate to violent criminal involvement. Finally, we explore the potential role of gene–environment interactions as they relate to the development of violent criminal tendencies and discuss the various explanatory perspectives that are used to explain gene–environment interactions as they relate to crime and violence.

Social Bias and the Development of Self-Control Results From a Longitudinal Study of Children and Adolescents

Gottfredson and Hirschi’s general theory of crime has sparked a tremendous amount of research examining the link between levels of self-control and involvement in delinquent and criminal acts. Recently, studies testing this theory have begun to investigate the factors that are related to the development of self-control. The current study expands on this body of research by examining whether social bias, as measured by the ability to identify facial expressions, contributes to variation in self-control in a sample of children. Analysis of data drawn from the National Survey of Children revealed some evidence that children who had difficulty correctly identifying facial expressions depicting fear and happiness had lower levels of self-control, whereas errors in identifying faces expressing anger were related to higher levels of self-control. The authors discuss the need for Gottfredson and Hirschi’s theory on the development of self-control to be expanded.