Sex differences in property crime in a Danish adoption cohort

Re-Examining of Moffitt's Theory of Delinquency through Agent Based Modeling

Moffitt’s theory of delinquency suggests that at-risk youths can be divided into two groups, the adolescence- limited group and the life-course-persistent group, predetermined at a young age, and social interactions between these two groups become important during the adolescent years. We built an agent-based model based on the microscopic interactions Moffitt described: (i) a maturity gap that dictates (ii) the cost and reward of antisocial behavior, and (iii) agents imitating the antisocial behaviors of others more successful than themselves, to find indeed the two groups emerging in our simulations. Moreover, through an intervention simulation where we moved selected agents from one social network to another, we also found that the social network plays an important role in shaping the life course outcome.

Implications of antisocial parents

Antisocial behavior is a socially maladaptive and harmful trait to possess. This can be especially injurious for a child who is raised by a parent with this personality structure. The pathology of antisocial behavior implies traits such as deceitfulness, irresponsibility, unreliability, and an incapability to feel guilt, remorse, or even love. This is damaging to a child's emotional, cognitive, and social development. Parents with this personality makeup can leave a child traumatized, empty, and incapable of forming meaningful personal relationships. Both genetic and environmental factors influence the development of antisocial behavior. Moreover, the child with a genetic predisposition to antisocial behavior who is raised with a parental style that triggers the genetic liability is at high risk for developing the same personality structure. Antisocial individuals are impulsive, irritable, and often have no concerns over their purported responsibilities. As a parent, this can lead to erratic discipline, neglectful parenting, and can undermine effective care giving. This paper will focus on the implications of parents with antisocial behavior and the impact that this behavior has on attachment as well as on the development of antisocial traits in children.

The genetic and environmental etiology of antisocial behavior from childhood to emerging adulthood

Previous research suggests that both genetic and environmental influences are important for antisocial behavior across the life span, even though the prevalence and incidence of antisocial behavior varies considerably across ages. However, little is known of how genetic and environmental effects influence the development of antisocial behavior. A total of 2,600 male and female twins from the population-based Swedish Twin Registry were included in the present study. Antisocial behavior was measured on four occasions, when twins were 8-9, 13-14, 16-17, and 19-20 years old. Longitudinal analyses of the data were conducted using structural equation modeling. The stability of antisocial behavior over time was explained by a common latent persistent antisocial behavior factor. A common genetic influence accounted for 67% of the total variance in this latent factor, the shared environment explained 26%, and the remaining 7% was due to the non-shared environment. Significant age-specific shared environmental factors were found at ages 13-14 years, suggesting that common experiences (e.g., peers) are important for antisocial behavior at this age. Results from this study show that genetic as well as shared environmental influences are important in antisocial behavior that persists from childhood to emerging adulthood.

Gender, genetic risk, and criminal behavior

The threshold hypothesis asserts that the prevalence of offending is lower among females because females have a higher threshold for risk than males. As a result, females who do offend should exhibit greater concentrations of genetic and environmental risk than male offenders. In light of these statements, the current study examines the role of genetic factors in the etiology of female offending using data from the National Longitudinal Study of Adolescent Health. The results reveal that the genetic risk threshold is higher for females than for males. However, contrary to the threshold hypothesis, female offenders exhibit fewer genetic risks than male offenders.

The sociopathy of sociobiology

Mealey's evolutionary reasoning is logically flawed. Furthermore, the evidence presented in favor of a genetic contribution to the causation of sociopathy is overinterpreted. Given the potentially large societal impact of sociobiological speculation on the roots of criminality, more-than-usual caution in interpreting data is called for.

Prisoner's Dilemma, Chicken, and mixedstrategy evolutionary equilibria

Mealey's interesting interpretation of sociopathy is based on an inappropriate two-person game model. A multiperson, compound game version of Chicken would be more suitable, because a population engaging in random pairwise interactions with that structure would evolve to an equilibrium in which a fixed proportion of strategic choices was exploitative, antisocial, and risky, as required by Mealey's interpretation.

Genetic mediation of longitudinal associations between family environment and childhood behavior problems

Previous studies have reported significant associations between measures of the family environment and behavior problems in children. However, because children in these studies were genetically related to their parents, such links may not be caused solely by environmental influences. The goal of this study was to investigate genetic influence on associations between family environment and problem behavior using an adoption design. Participants in the study included 179 adopted and 176 nonadopted children, as well as their parents and teachers, in the Colorado Adoption Project (CAP; Plomin, DeFries, & Fulker, 1988). Mothers and fathers each completed the Family Environment Scale (FES) when their child was 1, 3, and 5 years of age; the child's problem behavior at age 7 was rated by both mothers and teachers using the Child Behavior Checklist (CBCL). Patterns of correlations for nonadopted versus adopted boys indicated that associations between aspects of the family's relationship (conflict, cohesion, expressiveness) and behavior problems in home and school were mediated genetically. For girls, however, these links appeared to be influenced by direct shared environmental effects.

Genetic evidence that Darwin was right about criminality: nature, not nurture

Darwin maintained that man's behaviours, just as the ones of the lower animals, are not cultural products of learning, but constitute evolutionarily selected innate traits that can be transmitted through biological inheritance. Coherently, Darwin wrote that "some elimination of the worst dispositions is always in progress... Malefactors are executed...so that they cannot freely transmit their bad qualities". Darwin's evolutionary deterministic views about the innateness of human behaviours and the heritability of criminal tendencies proved genially farsighted. Indeed, the scientific evidence that they are genetically determined became indisputable just in this century, about 120 years after Darwin's death. This article, besides discussing human genetic variation and the genetic basis of pro-social traits, focuses on the recent and mounting evidence that points to genes for antisocial behaviours, genes for criminality, and genes for violence. All of them contribute to discredit further the scientifically untenable cultural dogma claiming that human behaviours reflect nurture, represented by social environments, not nature, in the form of biological factors. Genes for criminality and violence also concur to demolish the ideological dogma espoused by those who assert that criminality is a result of poverty and unemployment. The falsity of that politically biased dogma, as argued in this article, is also demonstrated by the fact that Brazil, despite significant reductions of poverty, socioeconomic disparities, and unemployment during the last five years, is facing a spiralling increase in criminal misdeeds, including homicides, which have reached an alarming rate that is nearly fivefold higher than the already worrying one of the USA.

Genetic and environmental bases of childhood antisocial behavior: a multi-informant twin study

Genetic and environmental influences on childhood antisocial and aggressive behavior (ASB) during childhood were examined in 9- to 10-year-old twins, using a multi-informant approach. The sample (605 families of twins or triplets) was socioeconomically and ethnically diverse, representative of the culturally diverse urban population in Southern California. Measures of ASB included symptom counts for conduct disorder, ratings of aggression, delinquency, and psychopathic traits obtained through child self-reports, teacher, and caregiver ratings. Multivariate analysis revealed a common ASB factor across informants that was strongly heritable (heritability was .96), highlighting the importance of a broad, general measure obtained from multiple sources as a plausible construct for future investigations of specific genetic mechanisms in ASB. The best fitting multivariate model required informant-specific genetic, environmental, and rater effects for variation in observed ASB measures. The results suggest that parents, children, and teachers have only a partly "shared view" and that the additional factors that influence the "rater-specific" view of the child's antisocial behavior vary for different informants. This is the first study to demonstrate strong heritable effects on ASB in ethnically and economically diverse samples.

Problem behavior and romantic relationships: assortative mating, behavior contagion, and desistance

Antisocial behavior and substance misuse are forms of problem behavior demonstrating considerable continuity over time. Accordingly, problem behavior influences interpersonal contexts across the life course, which may result in the replication of coercive interactions and a problem behavior lifestyle within romantic relationships. Furthermore, theories of self-selection, and associated research, suggest that individuals pick companions compatible with, and supportive of, their behavior, leading to high levels of similarity between romantic partners and the potential reinforcement of problem behavior over time. However, some research suggests that romantic relationships may play a positive role and facilitate desistance from problem behavior. The purpose of this paper is to explore how antisocial behavior and substance use both influence and are influenced by romantic relationships in late adolescence and early adulthood. We first review research regarding the extent of, and processes underlying, partner similarity in problem behavior. Next, we examine how romantic relationships may promote the desistance of problem behavior. Finally, we discuss possible moderators of the association between problem behavior and romantic relationships, as well as limitations, intergenerational implications, and recommended future directions of the reviewed research.

Genetic and Environmental Influences on Antisocial Behaviors: Evidence from Behavioral–Genetic Research

This article reviews behavioral-genetic research into human antisocial behavior. The focus is on studies of antisocial behavior that have been leading the way in investigating environmental and genetic influences on human behavior. The first generation of studies, which provided quantitative estimates attesting that genes and environments each influence about half of the population's variation in antisocial behaviors is interpreted. Then how behavioral-genetic methods are being applied to test developmental theory and to detect environmental causes of antisocial behavior is illustrated. Evidence for interactions between genes and the environment in the etiology of antisocial behavior is also examined. The article ends by envisioning future work on gene-environment interplay in the etiology of antisocial behavior.

Using sex differences in psychopathology to study causal mechanisms: unifying issues and research strategies

BACKGROUND

Although there is an extensive literature, both speculative and empirical, on postulated differences between males and females in their rates of particular types of disorder, very little is known about the mechanisms that underlie these sex differences. The study of mechanisms is important because it may provide clues on aetiological processes. The review seeks to outline what is known, what are the methodological hazards that must be dealt with, and the research strategies that may be employed.

METHODS

We note the need for representative general samples, and for adequate measurement and significance testing if valid conclusions are to be drawn. We put forward three levels of causes that have to be considered: a genetically determined distal basic starting point; the varied consequences of being male or female; and the proximal risk or protective factors that are more directly implicated in the causal mechanisms that predispose to psychopathology. In delineating these, we argue that three key sets of evidential criteria have to be met: a) that the risk factors differ between males and females; b) that they provide for risk or protection within each sex; and c) that when introduced into a causal model, they eliminate or reduce the sex differences in the disorders being studied.

RESULTS

A male excess mainly applies to early onset disorders that involve some kind of neurodevelopmental impairment. A female excess mainly applies to adolescent-onset emotional disorders. No variables have yet met all the necessary criteria but some good leads are available. The possible research strategies that may be employed are reviewed.

CONCLUSIONS

The systematic investigation of sex differences constitutes an invaluable tool for the study of the causal processes concerned with psychopathology.

Using MZ differences in the search for nonshared environmental effects

Behavioural genetic research has shown that environmental influences relevant to the development of individual differences are largely nonshared in origin. That is, environmental influences do not make children in the same family similar to one another, however, little is known about which specific aspects of the environment are responsible. Identical (MZ) twins provide a uniquely powerful tool to search for specific nonshared environmental influences independent of nonshared genetics because such twins do not differ genetically. The sample consisted of 93 MZ twin pairs aged 10-18 years from the Nonshared Environment and Adolescent Development (NEAD) project. Reports of parental negativity and adolescent adjustment were obtained from parents, ratings of videotaped observations, and the adolescents themselves. Relative differences of mothers' and fathers' negativity within MZ pairs correlated significantly with MZ differences in antisocial behaviour. The correlations were moderate for within-reporter associations, but were negligible for associations between reporters. Possible interpretations for these source-specific findings are discussed.

Fatherless rearing leads to sociopathy

Endorsing Mealey's analysis, it is pointed out that increasing rates of crime and violence are due to increasing proportions of children being reared in circumstances radically different from the extendedfamily environment to which we are evolntionarily adapted, that is, they are reared without fathers.

Sociopathy and sociobiology: Biological units and behavioral units

Behavioral biologists have long sought to link behavioral units (e.g., aggression, depression, sociopathy) with biological units (e.g., genes, neurotransmitters, hormones, neuroanatomical loci). These units, originally contrived for descriptive purposes, often lead to misunderstandings when they are reified for purposes of causal analysis. This genetic and biochemical explanation for sociopathy reflects such problems.

Is sociopathy a type or not? Will the “real” sociopathy please stand up?

The validity of the classification of “primary sociopaths” as a qualitatively distinct group in the general population is questioned. Cenetic variation in the experience and expression of emotions may play a role in the development of antisocial behavior. However, research clearly documents that socialization environments powerfully modify the expression of genetic biases in a manner that increases or decreases the risk for “sociopathy.”

Sociobiology, sociopathy, and social policy

Evolutionary analysis suggests that policies based on deterrence may cope effectively with primary sociopathy if the threat of punishment fits the crime in the cost/benefit calculus of the sociopath, not that of the public. On the other hand, policies designed to offset serious disadvantage in social competition may help inhibit the development of secondary sociopathy, rather than deter its expression.

Implications of an evolutionary biopsychosocial model

Mealey's work has several interesting implications: It refutes the charge that sociobiology paints a cynical portrait of human nature and adopts a one-sided reductionism; it exemplifies a general theoretical scheme for constructing evolutionary biopsychosocial models of human behavior; and it has the practical effect of promoting and informing early intervention in children at risk for psychopathic disorder.

The role of attachment in the development and prevention of sociopathy

Mealey's sociobiological model of sociopathy could profit from attachment theory, in particular, the theory and research on the basis of the Adult Attachment Interview (Main & Goldwyn 1985–1993). Findings of an adult attachment study in a forensic psychiatric setting are summarized. Three attachment-oriented strategies for families, schools, and forensic settings are proposed to help reduce or prevent secondary sociopathy and criminal recidivism.

The role of emotion in sociopathy: Contradictions and unanswered questions

Emotion is critical in Mealey's conceptual arguments. However, several of her assertions about the role of emotion in sociopathy are problematic. Questions are raised regarding the link between lack of anxiety and low levels of secondary emotions such as love and sympathy, the argument that sociopaths are low in anxiety but high in neuroticism, and the designation of anxiety as a secondary emotion.

Psychopathy and violence: Arousal, temperament, birth complications, maternal rejection, and prefrontal dysfunction

The key questions arising from Mealey's analysis are: Do environmental factors such as early maternal rejection also contribute to the emotional deficits observed in psychopaths? Are there psychophysiological protective factors for antisocial behavior that have clinical implications? Does a disinhibited temperament and low arousal predispose to primary psychopathy? Would primary or secondary psychopaths be most characterized by prefrontal dysfunction?