Digit ratio (2D:4D), sex differences, allometry, and finger length of 12-30-year olds: Evidence from the British Broadcasting Corporation (BBC) internet study

2010 ◽  
Vol 22 (5) ◽  
pp. 604-608 ◽  
Author(s):  
John T. Manning
2007 ◽  
Vol 105 (1) ◽  
pp. 143-152 ◽  
Author(s):  
Martin Voracek ◽  
Denise Offenmuller

Sex and side differences in relative thumb length of children and adolescents have been reported by prior researchers. These findings mirror those reported for the second-to-fourth digit ratio (2D:4D), a likely biomarker for the organizational (permanent) effects of prenatal androgens on the human brain and body. The present study investigated relative thumb length, in particular, its associations with all possible digit ratios (2D:3D, 2D:4D, 2D:5D, 3D:4D, 3D:5D, and 4D:5D), in a sample of young adults (60 men and 64 women). Relative thumb length was less precisely measurable than direct or image-based finger-length measurements, as used in digit ratio research. There were no significant sex or side differences in relative thumb length. Contrary to expectation, thumb size was not positively correlated with any digit ratios. Relative thumb length appears to be developmentally unstable (decreases during childhood and adolescence). Additional findings, such as the magnitude ranking of sex differences in digit ratios and the comparability of direct versus image-based finger-length measurements, are also discussed.


2010 ◽  
Vol 69 (1) ◽  
pp. 31-37 ◽  
Author(s):  
Martin Voracek ◽  
Kerstin Schicker

Relationships of second-to-fourth digit ratio (2D:4D) versus absolute finger length, two putative markers for prenatal vs. pubertal-adolescent testosterone exposure, with specific behavioral responses to interpersonal conflict, as assessed with the Conflict Dynamics Profile (CDP; Davis, Capobianco, & Kraus, 2004), were examined in an adult community sample of 132 men and women. Paralleling related findings for specific types of aggression (namely, reactive and indirect, i.e., social/relational aggression), results showed analogous sex differences for conflict-related behaviors. Specifically, women scored significantly higher than men on the CDP Hot Buttons component, assessing upset in response to workplace-related conflict elicited by problematic behavior of workmates. Among women (but not men), higher Hot Button scores corresponded significantly to higher prenatal testosterone (indexed by lower 2D:4D). Extending previous evidence for associations between 2D:4D and aggression, this suggests possible contributions of prenatal sex-hormonal masculinization to within-sex individual variation in specific types of conflict-related behavior.


2021 ◽  
Author(s):  
Martin Voracek

The second-to-fourth digit ratio (2D:4D) is a sexually differentiated trait of human hand anatomy which presently is frequently used in anthropological, biomedical, and psychological studies as a putative (retrospective and indirect) marker for prenatal androgen levels. Apart from the traditionally studied 2D:4D ratio, five further finger-length ratios can be constructed for the human hand (2D:3D, 2D:5D, 3D:4D, 3D:5D, 4D:5D). These have been probed by only a minority of digit ratio studies. It is not firmly established whether all of these finger-length ratios actually exhibit sex differences and whether 2D:4D indeed is the most sexually differentiated among them. To clarify these questions, a meta-analysis on studies reporting data from mixed-sex samples on all six finger-length ratios of the right and left hands in healthy normals was conducted. This study inclusion criterion was satisfied by 18 independent samples (including two unpublished), representing 4198 individuals (1989 men and 2209 women), seven countries (Australia, Austria, China, Greece, Jamaica, the UK, and the USA), different age bands (child, young adult, and adult samples), and different finger-length measurement methods (from printouts of flatbed-scanned images or photocopies of the hands or direct measurements). The meta-analytical results showed that men invariably had lower finger-length ratios than women. Although these sex differences were significant for all six finger-length ratios, effects were not strong, but rather ranged from small (d=-0.21, for right-hand 4D:5D) to medium (d= 0.44, for right-hand 2D:4D). 2D:5D was equally sexually differentiated as 2D:4D. Sex differences for finger-length ratios calculated from nonadjacent fingers (2D:4D, 2D:5D, 3D:5D) generally were somewhat more pronounced than for those calculated from adjacent fingers (2D:3D, 3D:4D, 4D:5D). Discussed are practical consequences of these findings for digit ratio research.


Bird Study ◽  
2019 ◽  
Vol 66 (4) ◽  
pp. 503-509 ◽  
Author(s):  
Piotr P. Kazimirski ◽  
Mikołaj Kaczmarski ◽  
Magdalena M. Zagalska-Neubauer ◽  
Katarzyna M. Żołnierowicz ◽  
Marcin Tobółka

2005 ◽  
Vol 272 (1571) ◽  
pp. 1473-1479 ◽  
Author(s):  
Matthew H McIntyre ◽  
Peter T Ellison ◽  
Daniel E Lieberman ◽  
Ellen Demerath ◽  
Bradford Towne

Relative finger lengths, especially the second-to-fourth finger length ratio, have been proposed as useful markers for prenatal testosterone action. This claim partly depends on an association of relative finger lengths in adults with related sex differences in children and infants. This paper reports the results of a study using serial radiographs to test for both sex differences in the fingers of infants and children and for a relationship between sex differences in the children and infant finger and adult finger length ratios. This is the first study using long-term serial data to evaluate the validity of finger length ratios as markers. We found not only that sex differences in finger length ratios arise prior to puberty, but that sex differences in the fingers of children are highly correlated with adult finger length ratios. Our results strongly encourage the further use of finger length ratios as markers of perinatal testosterone action.


2021 ◽  
pp. 1-9
Author(s):  
J.T. Manning ◽  
B. Fink ◽  
L. Mason ◽  
R. Trivers

Abstract Income inequality is associated positively with disease prevalence and mortality. Digit ratio (2D:4D) – a negative proxy for prenatal testosterone and a positive correlate of prenatal oestrogen – is related to several diseases. This study examined the association of income inequality (operationalized as relative parental income) and children’s 2D:4D. Participants self-measured finger lengths (2D=index finger, and 4D=ring finger) in a large online survey conducted in July 2005 (the BBC Internet Study) and reported their parents’ income. Children of parents of above-average income had low 2D:4D (high prenatal testosterone, low prenatal oestrogen) while the children of parents of below-average income had high 2D:4D (low prenatal testosterone, high prenatal oestrogen). The effects were significant in the total sample, present among Whites (the largest group in the sample), in the two largest national samples (UK and USA) and were greater for males than females. The findings suggest a Trivers-Willard effect, such that high-income women may prenatally masculinize their sons at the expense of the fitness of their daughters. Women with low income may prenatally feminize their daughters at the fitness expense of their sons. The effect could, in part, explain associations between low income, high 2D:4D (low prenatal testosterone) and some major causes of mortality such as cardiovascular disease.


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