Gender Differences and Relationship of 2D:4D-Ratio, Mental Toughness and Dark Triad Traits among Active Young Adults

SIMPLE SUMMARY: There is evidence that the exposure to more testosterone and less estrogen hormones before birth, that is, in utero, has a physiological impact on the relation between the index finger (2D) and the ring finger (4D). This relation is called the 2D:4D-ratio. A lower 2D:4D-ratio mirrors a longer ring finger (4D), relative to the index finger (2D); a higher 2D:4D-ratio mirrors a shorter ring finger (4D), relative to the index finger (2D). A higher exposure to testosterone and a lower exposure to estrogen hormones are associated with a lower 2D:4D-ratio. Further, a higher exposure to androgen hormones is associated with higher masculine traits. In the present study, we assessed 460 physically active young male and female adults. We showed that (1) males had lower 2D:4D ratios than females. Next, (2) active females and males had similar personality and mental toughness traits. (3) Females with more “dark” personality traits had a higher ability to perform consistently under stress and pressure; such females were mentally tougher. (4) Males with lower 2D:4D-ratios were mentally tougher. Overall, there is evidence that prenatal exposure to androgen hormones and personality traits in adulthood appear to be related, though, in a different fashion between male and female adults. ABSTRACT: There is consistent evidence that prenatal exposures to higher testosterone and lower estrogen concentrations during the first trimester of embryonal and fetal development are associated with a lower 2D:4D-ratio, which is to say: The index finger (2D) is shorter, compared to the ring finger (4D). Compared to non-active, athletes show lower 2D:4D ratios. However, athletes also report specific personality traits such as mental toughness, assertiveness, and competitive behavior. Here, we tested if 2D:4D-ratios were related to specific personality traits. We further investigated possible gender differences. A total of 460 active young adults (mean age: 24.81 years; 67% females) completed a series of self-rating questionnaires covering sociodemographic information and traits of the dark triad and mental toughness. Participants also provided a scan of their right palm hand to measure and calculate 2D:4D-ratios. t-tests, Pearson’s correlations, and multiple regression analysis were performed to analyze data. Compared to male participants, female participants had a higher 2D:4D-ratio. Female and male participants did not differ as regards dark triad traits and mental toughness traits. Irrespective of gender, and based on correlational computations, 2D:4D-ratios were unrelated to the dark triad (DT) and mental toughness (MT) scores. Higher DT scores were modestly associated with higher MT scores among females, but not among males. Lower 2D:4D-ratios were associated with higher constancy scores and the male gender. The constancy and male gender appeared to be associated with lower 2D:4D-ratios.