The association between the 2D:4D ratio and psychopathic characteristics.

Prior research has identified relations between prenatal testosterone exposure and various antisocial and criminal behaviors. However, less is known about the association between prenatal testosterone exposure and personality traits, such as psychopathy. This study used self-report and biometric data from a sample of undergraduates (n = 491) at a large southwestern university to examine the association between prenatal testosterone exposure (measured by the 2D:4D ratio) and three dimensions of psychopathy (i.e., callousness, egocentricity, and antisocial behavior). Analyses were stratified by sex to explore sex-specific biological underpinnings of psychopathy in young adulthood. Results showed that males scored significantly higher in psychopathic traits and reported significantly lower 2D:4D ratios, compared to females. Additionally, 2D:4D ratios were negatively associated with egocentricity in males, but not females. These findings contribute to a growing literature on the organizational effects that prenatal testosterone exposure may have on the development of different dimensions of psychopathy.

Testosterone, cortisol, and criminal behavior in men and women.

Only two studies to date have considered the joint effects of testosterone and cortisol on direct measures of criminal behavior. The current study extends this earlier work by incorporating the direct and interactive effects of baseline hormone measures and hormone change scores in response to social stress. The current study also extends prior work by considering distinct measures of different criminal behavior types and sex differences. Analyses based on a large sample of undergraduates indicated that testosterone had a positive and statistically significant association with impulsive and violent criminal behavior. The interaction of testosterone with cortisol had a negative association with income generating crime. Simple slopes analyses of this interaction indicated testosterone had a positive association with income generating crime when cortisol was low (-1 SD). Associations between hormones and criminal behavior were not moderated by sex.

Examining the Relationship Between Victimization, Psychopathy, and the Acceptance of Rape Myths.

Rape myths are attitudes that implicitly and explicitly blame victims for their own sexual victimization. Greater adherence to rape myths is linked to several negative outcomes, including the neutralization of gender-based violence and the perpetration of sexual violence. Few studies have considered how previous life experiences and individual-level traits influence the development and greater adherence to rape myths. The current study examines how traits associated with the three-factor model of psychopathy (i.e., egocentric, callous, and antisocial dimensions) and adherence to traditional gender roles mediate the relationship between prior childhood/adolescent victimization and the acceptance of rape myths in a sample of college men and women (N = 789). Path modeling indicates that experiences of psychological victimization (before age 16) increased egocentric psychopathic traits, which then increased the acceptance of rape myths in men. In women, however, sexual victimization (before age 16) increased the acceptance of traditional gender roles, which then influenced the acceptance of rape myths. Additionally, the egocentric facet of psychopathy exerted indirect effects on the acceptance of rape myths through traditional views on gender roles in both men and women. These findings highlight the need to continue to examine egocentric personality traits in relation to the development of rape myths in adolescent and young adult populations. Directions for collegiate programming are discussed.

An exploratory analysis of testosterone, cortisol, and aggressive behavior type in men and women.

Increasing evidence indicates that the interaction between testosterone and cortisol is associated with variation in aggressive behavior. However, results are mixed. The current study further explored the association between testosterone, cortisol, and both reactive and proactive aggression in a large sample of university students. Models considered direct and interactive effects between baseline measures of testosterone and cortisol as well as change in hormones in response to a social stressor. In women, baseline cortisol had a negative direct association with reactive aggression and was further associated with reactive aggression in interaction with baseline testosterone (positive interaction). Hormones were unrelated to reactive aggression in men. Baseline cortisol had a negative direct association with proactive aggression in women. In contrast, the association between change in cortisol and proactive aggression was positive. Cortisol was not associated with proactive aggression in men. In addition, testosterone was not related to proactive aggression either directly or in interaction with cortisol in either men or women. Collectively, these results show that the association between hormones and aggression varies across aggressive behavior type and across sex.

Further Evaluation of the Associations Between Psychopathic Traits and Symptoms of PTSD and Depression in a Nonclinical Sample.

Examining psychopathic traits at the factor or facet level has revealed that various aspects of psychopathy may be differentially related, even in opposing directions, to important outcomes (e.g., intelligence, emotion regulation). Empirical work on relations between psychopathy and internalizing disorders, such as posttraumatic stress disorder (PTSD) and depression, has provided evidence for a positive association with antisocial traits. However, findings for the affective domain have been more equivocal. The current study (N = 732) sought to replicate past findings of the positive association of antisocial psychopathic traits with higher levels of PTSD and depressive symptoms, and to further explore associations between affective traits of psychopathy and these disorders using two measures of psychopathy. Results confirmed prior findings of a positive correlation between antisocial features and self-reported PTSD/Depression symptom severity, but they did not provide evidence for any association with affective traits. Future research using longitudinal designs is needed to begin establishing temporal ordering of the psychopathy-internalizing relationship.

Low Resting Heart Rate and Stalking Perpetration.

There is consistent evidence to suggest that individuals with low resting heart rate are more likely to engage in a variety of antisocial behaviors. The present study examines whether this finding can be extended to stalking perpetration. Drawing from fearlessness theory and stimulation-seeking theory, as well as conceptual work of Meloy and Fisher, we find that individuals with low resting heart rates had significantly greater odds of engaging in stalking behavior, net of controls for sex, age, race, self-control, parental affection, delinquent peers, attitudes/beliefs toward crime, and aggression. When disaggregated by sex, the heart rate-stalking relationship was found to be significant for males, but not for females. The implications of these findings are discussed from a biosocial perspective.

Skin conductance, heart rate and aggressive behavior type.

The current study tested the association between physiology and aggressive behavior type in a large sample of University students (N = 509). Measures of aggression were gathered with the Reactive and Proactive Aggression Questionnaire. Analyses used raw aggressive behavior type scores and residualized measures of aggressive behavior type, which account for the overlap between reactive and proactive aggression. Measures of physiology included skin conductance and heart rate, both at rest and in response to a minor social stressor. Analyses assessed the association between aggressive behavior type and measures of physiology in the full sample and in sex specific sub-samples. Results indicated that resting skin conductance was positively associated with proactive aggression in the full sample and among females. Skin conductance in response to stress had a positive association with reactive aggression both in the full sample and among males. Skin conductance responsivity was negatively associated with proactive aggression among males. Findings further strengthen previous work suggesting that the etiologies of reactive and proactive aggression are distinct and may vary across sex.