Manning John, Kilduff Liam, Cook Christian, Crewther Blair, Fink Bernhard
Department of Psychology, Northumbria University , Newcastle upon Tyne , UK.
Applied Sports Technology, Exercise and Medicine Research Centre, Swansea University , Swansea , UK.
Front Endocrinol (Lausanne). 2014 Jan 30;5:9. doi: 10.3389/fendo.2014.00009. eCollection 2014.
Digit ratio (2D:4D) denotes the relative length of the second and fourth digits. This ratio is considered to be a biomarker of the balance between fetal testosterone (T) and estrogen (E) in a narrow window of early ontogeny. Evidence for this assertion is derived from direct and indirect measures of prenatal hormonal exposure (in experimental animals, via amniotic fluid samples and in the study of sex-typical traits) in relation to 2D:4D. In contrast, the relationships between 2D:4D and levels of sex steroids in adults are less clear, as many correlational studies of 2D:4D and adult sex steroids have concluded that this association is statistically non-significant. Here, we suggest that in order to understand the link between 2D:4D and sex hormones, one must consider both fetal organizing and adult activating effects of T and E. In particular, we hypothesize that 2D:4D correlates with organizing effects on the endocrine system that moderate activating effects in adulthood. We argue that this is particularly evident in "challenging" conditions such as aggressive and sexual encounters, in which individuals show increased levels of T. We discuss this refinement of the 2D:4D paradigm in relation to the links between 2D:4D and sports performance, and aggression.
指长比（2D:4D）表示第二和第四指的相对长度。该比例被认为是早期个体发育狭窄窗口期胎儿睾酮（T）和雌激素（E）之间平衡的生物标志物。这一论断的证据来自于与2D:4D相关的产前激素暴露的直接和间接测量（在实验动物中，通过羊水样本以及在性典型特征研究中）。相比之下，2D:4D与成人性类固醇水平之间的关系尚不清楚，因为许多关于2D:4D与成人性类固醇的相关性研究得出结论，这种关联在统计学上不显著。在此，我们认为，为了理解2D:4D与性激素之间的联系，必须同时考虑T和E的胎儿组织化作用和成人激活作用。特别是，我们假设2D:4D与内分泌系统的组织化作用相关，这种作用会调节成年期的激活作用。我们认为，这在诸如攻击性和性接触等“具有挑战性”的情况下尤为明显，在这些情况下个体的T水平会升高。我们讨论了2D:4D范式的这种细化与2D:4D和运动表现以及攻击性之间的联系。
