Digit ratio (2D:4D) and sex-role orientation: Further evidence and meta-analysis

Three new studies (N = 132, 623, 1112) did not yield hypothesized associations between digit ratio (2D:4D), an assumed negative correlate of prenatal testosterone, and psychometrically measured sex-role orientation (positive association with femininity, negative ones with masculinity and masculinity-femininity difference scores) among heterosexuals of either sex. Meta-analysis of the pertinent literature (N = 6311, 28 studies from 10 countries, 46% unpublished) showed only men’s (but not women’s) left-hand (but not right-hand) 2D:4D reliably related as expected (positively) to femininity. This effect was tiny (0.14% attributable variance) and possibly non-robust (crucially dependent on one large study included). Hence, the cumulative evidence does not support systematic, robust, noteworthy within-sex correlations between 2D:4D and the masculinity/femininity personality dimensions.     

Testosterone and domain-specific risk: Digit ratios (2D:4D and rel2) as predictors of recreational, financial, and social risk-taking behaviors

Prenatal testosterone has important effects on brain organization and future behavior. The second-to-fourth digit length ratio (2D:4D), a proxy of prenatal testosterone exposure, has been linked to a wide variety of sexually differentiated dispositions and behaviors. We examine the relationship between digit length ratios (2D:4D and rel2, the length of the second finger relative to the sum of the lengths of all four fingers) and risk-taking behaviors across five domains: financial, social, recreational, ethical, and health. In a sub-sample of male Caucasians (ethnically homogeneous), lower rel2 was predictive of greater financial, social, and recreational risk-taking, whereas lower 2D:4D was predictive of greater risk-taking in two domains (social and recreational). In the full male sub-sample (ethnically heterogeneous), the only significant correlation was a negative association between 2D:4D and financial risk. A composite measure of risk-taking across all five domains revealed that both rel2 and 2D:4D were negatively correlated with overall risk-taking in both male sub-samples. No significant correlations were found in the female sub-samples. Finally, men were more risk-seeking than women across all five contexts.     

Masculinised brain and romantic jealousy: Examining the association between digit ratio (2D:4D) and between- and within-sex differences

We examined the relationship between second-to-fourth digit ratio (2D:4D), a correlate of prenatal testosterone exposure, and distress at sexual versus emotional infidelity in hypothetical scenarios of relationship threat. As predicted, a significant negative association was found between 2D:4D and greater distress at sexual infidelity for the whole sample (N = 179, females = 101). While this novel finding supports the view of romantic jealousy as a sexually-dimorphic adaptation, we explore reasons for the relatively weak association and discuss how underlying differences in brain structure could have influenced sex-specific behavioural capacities in romantic jealousy. We suggest a useful direction for future research will be to develop novel methods that facilitate the investigation of implicit emotional, rather than explicit cognitive, processes in response to pair-bond threat.     

Power,testosterone, and risk‐taking

Power has been found to increase risk‐taking (Anderson & Galinsky, 2006 ) but this effect appears to be moderated by individual differences in power motivation (Maner, Gailliot, Butz, & Peruche, 2007 ). Among individuals high in power motivation, the experience of power leads to more conservative decisions. As testosterone is associated with the pursuit of power and status (Dabbs & Dabbs, 2000 ), we reasoned that high‐testosterone individuals primed with power might be similarly risk‐avoidant. Conversely, we hypothesized that high‐testosterone individuals primed with low power, would see risk‐taking as a vehicle for pursuing potential gains to their status and resources. We report findings from two experiments that are consistent with these predictions. In Experiment 1, higher testosterone males (as indicated by second–fourth digit ratio) showed greater risk‐taking when primed with low power. Experiment 2 replicated this effect and also showed that when primed with high power, higher testosterone males took fewer risks. Copyright © 2009 John Wiley & Sons, Ltd.     

Digit ratio (2D:4D) and Cattell's personality traits

The ratio between second and fourth finger (2D:4D) is sexually dimorphic; it is lower in men than in women. Studies using broad personality domains yielded correlations of 2D:4D with neuroticism, extraversion or agreeableness, but the obtained results have been inconsistent. We correlated 2D:4D of 184 women and 101 men with their scores in Cattell's 16 Personality Factor (16PF) Questionnaire. We found women with a higher (more ‘feminine’) right hand 2D:4D to score lower in emotional stability and social boldness and higher in privateness. Mediator analysis showed emotional stability to be probably primarily correlated with 2D:4D and to act as a mediator between 2D:4D and social boldness. Privateness appears to be mediated by an even more complex path. We discuss the usefulness of primary‐level personality questionnaires and mediator analyses in the investigation of psycho‐morphological associations. Copyright © 2007 John Wiley & Sons, Ltd.     

心理学视野下的面孔宽长比研究

面孔宽长比（fWHR）是指面孔宽度与长度（或高度）之间的比值。它是一种反映男性青春期睾酮分泌水平高低的面部结构,并被视为男性气质的评价指标。多项研究表明,fWHR与攻击、支配、冒险、欺骗、追求个体成就等男性气质行为相关。本文对该领域研究成果进行了详细述评,并指出未来研究可在性别差异、影响机制、跨文化研究等方面加以探讨。     

Hormones and competitive aggression in women

This study used diaries of competitive interactions to explore the relationship between hormones and competitive aggression in women. Thirty women completed approximately 10 diary entries each. In each entry, the women described a recent competitive interaction they had engaged in and noted whether it was expressed aggressively or through other tactics. Each woman received a score for the fraction of her competitive interactions that were expressed using physical aggression, verbal aggression, nothing overt, and so on. Hormones (total testosterone, free testosterone, androstenedione, estradiol, and cortisol) were measured in serum early in the follicular phase. Results indicate that women with low levels of androstenedione and total testosterone were less likely to express their competitive feelings overtly, while women with high levels of androstenedione were more likely than other women to express their competitive feelings through verbal aggression. Estradiol was unrelated to competitive tactics, but women with high estradiol levels reported fewer competitive interactions over athletics than did other women. Aggr. Behav. 29:107–115, 2003. © 2003 Wiley‐Liss, Inc.     

Androgen dynamics in the context of children's peer relations: an examination of the links between testosterone and peer victimization

Testosterone levels have been shown to decrease in the face of social defeat in several mammalian species. Among humans, the loss of social status has been studied primarily in the context of athletic competition, with winners having higher testosterone levels than losers. This study examined testosterone levels in relation to peer victimization (bullying) in a sample of 151 boys and girls aged 12–13. Statistically controlling for age and pubertal status, results indicated that on average verbally bullied girls produced less testosterone and verbally bullied boys produced more testosterone than their nonbullied counterparts. Similar trends were evident comparing social and physical bullying with testosterone. Sex differences are discussed in terms of empirically validated differences in coping styles, as girls tend to internalize, whereas boys tend to externalize, their abuse. Aggr. Behav. 35:103–113, 2009. © 2008 Wiley‐Liss, Inc.     

Fetal Testosterone,Socio‐Emotional Engagement and Language Development

The present study investigated the relations among fetal testosterone, child socio‐emotional engagement and language development in a sample of 467 children (235 boys) from the Western Australian Pregnancy Cohort (Raine) Study. Bioavailable testosterone concentration measured in umbilical cord blood taken at birth was found to be significantly negatively correlated with socio‐emotional engagement and vocabulary development for boys but not for girls. Socio‐emotional engagement mediated the effect of boys' fetal testosterone levels on their vocabulary development. However, the size of the effects was small, and fetal testosterone and socio‐emotional engagement were no longer significant predictors of boys' vocabulary scores after accounting for the effects of other predictors including maternal age and education, parity, and parent–child book reading. It is concluded that further research into these associations is warranted in both typical and atypical development and that this research would profit from including a broader focus on the role that proximal processes such as socio‐emotional engagement, joint attention and imitation have in mediating the developmental effects of prenatal factors such as fetal testosterone exposure. Copyright © 2012 John Wiley & Sons, Ltd.