Criminality and the 2D:4D ratio: testing the prenatal androgen hypothesis

The androgen receptor gene and criminal offending: Evidence derived from international data

Beginning early in fetal development, the androgen receptor (AR) gene helps regulate bodily exposure to testosterone. Most studies of individuals have found an inverse correlation between the number of CAG repeats on this gene and serious forms of physical aggression. This two-phased study was primarily undertaken to determine if a link between AR CAGn and physical aggression also exists at an ecological level of analysis. To make this assessment, we first conducted a bivariate analysis of the average number of AR CAG repeats for a large number of countries and the rates of crime victimization in those same countries. Except for motor vehicle theft, as the national average number of CAG repeats increased, crime victimization rates decreased. This inverse relationship was especially strong for violent offenses. In the second phase of this study, we sought to determine if per capita gross domestic product, pathogen prevalence, and average intelligence might be mediating some of the AR CAG repeats-criminality relationship. Mediation analysis analysis indicated that, once gross domestic product and pathogenic prevalence were controlled, average intelligence was able to eliminate most of the links between CAG repeats and crime victimization rates, especially in the case of violent offenses. These findings suggest that the AR gene is not influencing criminality primarily by altering testosterone brain exposure (as we suspected). Instead, it may affect criminality mainly by affecting cognitive ability. In fact, once average national intelligence is included in the mediation analysis model, direct relationships between CAG repeats and measures of homicide, assault, and robbery were no longer statistically significant. Findings from this two-phased study point toward the AR gene as having multiple effects on brain functioning, particularly regarding intellectual development as hypothesized by Manning [62]. Replication is obviously needed.

Association of 2D:4D finger length ratio of People Working in different professions with personality traits

Background

The ratio of the index finger (2nd finger) to the ring finger (4th finger) (2D:4D) can give information about harmony between personality and career of individuals. The developing technology makes it difficult to choose a profession.

Aim

This study aims to contribute to the career choice of individuals by analyzing the relationship between the 2D:4D finger digit ratio and personality traits of individuals working in different professions (Educator, Worker, Housewife, Civil servant, Healthcare professional/EWHCH).

Method

The participants were three hundred twenty-five individuals living in the province of Malatya. The SPSS 26.0 software was utilized in the data analysis. The p value of 0.05 was accepted as significance level in comparison tests.

Results

A statistically significant difference was determined between the participants, who had the 2D shorter than the 4D in right hand, in terms of professional groups (p < 0.05). In healthcare workers, a low level (r = 0.305) positive correlation was found between right hand 2D4D and both control (r = 0.264) and curiosity and left hand 2D:4D, and a low level (r = 0.255) negative correlation was found between Conscientiousness and right hand 2D:4D in housewives. There was a statistically significant difference between the groups (educator, worker, housewife, civil servant, healthcare professional) in terms of total score of the Five-Factor Personality Inventory (FFPI) and scores of extroversion, agreeableness, conscientiousness, neuroticism, and openness to experience subscales (p < 0.05). A weak positive statistically significant correlation was detected between the healthcare professionals' score of Career Adapt-abilities Scale (CAAS) control subscale and the right-hand 2D:4D ratio. Conclusions: It is suggested to investigate the 2D:4D ratio over different professional groups. The present study is important since it gives information about personality and associates such information with the 2D:4D ratio.

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.

A Context Dependent Interpretation of Inconsistencies in 2D:4D Findings: The Moderating Role of Status Relevance

Whereas direct relationships between 2D:4D and dominance related attitudes or behavior often turn out to be weak, some literature suggests that the relation between 2D:4D and dominance is context-specific. That is, especially in status-challenging situations 2D:4D may be related to dominant behavior and its correlates. Based on this perspective, we interpret inconsistencies in the literature on the relation between 2D:4D and risk taking, aggression and dominance related outcomes and investigate in our empirical study how attitudes in low 2D:4D men may change as a function of the status relevance of the context. We provide evidence for the idea that status relevance of the particular situation at hand influences the attitude towards performance-enhancing means for low 2D:4D men, but not for high 2D:4D men. We argue that 2D:4D may be related to any behavior that is functional to attain status in a specific context. Implications for (economic) decision making are discussed.

CAN BODY PROPORTIONS SERVE AS A PREDICTOR OF RISK-TAKING BEHAVIOURS IN WOMEN AND MEN?

The second to fourth digit ratio (2D:4D) is claimed to be a biomarker of prenatal sex steroids. This study compared 2D:4D and waist-hip ratio (WHR) in men and women with nose deformity caused by injuries suggesting risky behaviour with those of unaffected controls. This kind of facial trauma was accepted as an indicator of risk-taking behaviour. The study involved 100 patients (50 women aged 30.74±8.09 years and 50 men aged 30.98±10.86 years) who underwent rhinoplasty due to nose trauma in a hospital in Łódź, Poland, in 2015. For comparison purposes, a control sample of 70 women (aged 23.03±3.36 years) and 70 men (aged 22.87±3.46 years) was recruited. In both groups the following measurements were taken: body height, waist and hip circumferences, II and IV digit lengths and body weight. The results showed that women and men who had suffered nose injury had significantly higher values of WHR than controls. The 2D:4D in women with post-traumatic nose deformity was significantly different than the ratio in control women (p<0.0001) and presented the male pattern. It is concluded that in women risky behaviours seem to be associated with prenatal sex hormone influence, while differences in WHR suggest that this tendency is also related to postnatal hormonal factors. Risky behaviours in men should be linked to postnatal hormonal changes rather than to increased prenatal androgen exposure.

Congenital Adrenal Hyperplasia, Polycystic Ovary Syndrome and criminal behavior: A Swedish population based study

Both prenatal and circulating testosterone and other androgens have been suggested to influence the individual's propensity to commit crime, but empirical evidence is limited and inconsistent. Congenital Adrenal Hyperplasia (CAH) and Polycystic Ovary Syndrome (PCOS) are both hyperandrogenic conditions but with an important difference; whereas subjects with CAH are exposed to high concentrations of androgens in utero, women with PCOS are subjected to high androgens in adulthood. Comparing these groups can therefore yield important insights of androgenic effects on behavior. In the current study, information on medical diagnoses and convicted crimes were gathered from Swedish population-based registers. The associations between diagnoses of CAH or PCOS and any crime, violent crime or sex crime were estimated with conditional logistic regression. Results showed that CAH in women and men did not predict criminality, whereas an increased risk for any crime and violent crime was found in PCOS women. Our findings indicate that female hyperandrogenism in adulthood, but not prenatal hyperandrogenism, is associated with risk for criminal behavior. Further research into hyperandrogenic conditions holds opportunities to deepen our understanding of the etiology of crime and psychopathology.