Department of Psychology, University of Swansea, Wales, UK.
Laterality. 2011 Mar;16(2):136-55. doi: 10.1080/13576500903410369. Epub 2010 Jan 20.
The length of the index finger relative to that of the ring finger, the 2D:4D ratio, has been taken to be a marker of the amount of testosterone (T) that was present in the foetal environment (Manning, Scutt, Wilson, & Lewis-Jones, 1998). It has also been suggested (Geschwind & Galaburda, 1987) that elevated levels of foetal T are associated with left-handedness and that adult levels of circulating T might relate to foetal levels (Jamison, Meier, & Campbell, 1993). We used multiple regression analyses to investigate whether there is any relationship between either left or right hand 2D:4D ratio and handedness. We also examined whether adult levels of salivary T (or cortisol, used as a control hormone) predict digit ratio and/or handedness. Although the 2D:4D ratio of neither the left nor the right hand was related to handedness, the difference between the digit ratios of the right and left hands, D(R-L), was a significant predictor of handedness and of the performance difference between the hands on a peg-moving task, supporting previous findings (Manning & Peters, 2009; Manning et al., 1998; Manning, Trivers, Thornhill, & Singh, 2000; Stoyanov, Marinov, & Pashalieva, 2009). Adult circulating T levels did not predict the digit ratio of the left or right hand; nor was there a significant relationship between concentrations of salivary T (or cortisol) and either hand preference or asymmetry in manual skill. We suggest that the association between D(R-L) and hand preference arises because D(R-L) is a correlate of sensitivity to T in the developing foetus.
食指相对于无名指的长度，即 2D:4D 比率，被认为是胎儿环境中睾丸激素 (T) 含量的标志物 (Manning、Scutt、Wilson 和 Lewis-Jones，1998)。也有人提出 (Geschwind 和 Galaburda，1987)，胎儿 T 水平升高与左撇子有关，而循环 T 水平与胎儿时期有关 (Jamison、Meier 和 Campbell，1993)。我们使用多元回归分析来研究左手或右手的 2D:4D 比率与利手之间是否存在任何关系。我们还检查了唾液 T 水平（或作为对照激素的皮质醇）是否可以预测手指比率和/或利手。尽管左手和右手的 2D:4D 比率都与利手无关，但右手和左手之间的手指比率差异（D(R-L)）是利手和在 peg-moving 任务中双手表现差异的显著预测指标，支持了之前的发现 (Manning 和 Peters，2009；Manning 等人，1998；Manning、Trivers、Thornhill 和 Singh，2000；Stoyanov、Marinov 和 Pashalieva，2009)。成人循环 T 水平不能预测左手或右手的手指比率；唾液 T（或皮质醇）浓度与手偏好或手部技能的不对称性之间也没有显著关系。我们认为，D(R-L)与手偏好之间的关联是因为 D(R-L)是胎儿对 T 敏感性的相关指标。
