scholarly journals Is 2D:4D the most sexually differentiated among finger-length ratios? Answers from a meta-analysis

2021 ◽  
Author(s):  
Martin Voracek
Keyword(s):  
Sex Differences ◽  
Meta Analysis ◽  
Digit Ratio ◽  
Human Hand ◽  
Finger Length ◽  
Right Hand ◽  
The Usa ◽  
Scanned Images ◽  
The Uk ◽  
The Right

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 This study inclusion criterion was satisfied by 18 independent samples (including two unpublished), representing 4198 individuals (1989 men and 2209 women), seven countries (Australia, Austria, China, Greece, Jamaica, the UK, and the USA), different age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.

EVIDENCE FOR ASSORTATIVE MATING ON DIGIT RATIO (2D:4D), A BIOMARKER FOR PRENATAL ANDROGEN EXPOSURE

2007 ◽  
Vol 39 (4) ◽  
pp. 599-612 ◽  
Author(s):  
MARTIN VORACEK ◽  
STEFAN G. DRESSLER ◽  
JOHN T. MANNING
Keyword(s):  
Assortative Mating ◽  
Age Differences ◽  
Research Programme ◽  
Digit Ratio ◽  
Left Hand ◽  
Right Hand ◽  
Androgen Exposure ◽  
The Right ◽  
Prenatal Androgen ◽  
Spousal Similarity

SummaryThe second-to-fourth digit ratio (2D:4D) presents an anatomical sex difference in humans. On average, men tend to have lower 2D:4D compared with women. There is fairly strong evidence for a role of the 2D:4D ratio as a biomarker for the organizational (permanent) effects of prenatal testosterone on the brain and behaviour. Recently, an accumulating research programme has shown 2D:4D to be related to a multitude of sex-dependent, hormonally influenced biosocial traits and phenotypes which reach into the domains of ability, behaviour, fertility, health, personality and sexuality. This study investigated the degree of assortative mating (spousal similarity) in a sample of 239 native Austrian couples of parental or grandparental age, all of them having reproduced. Results included: (i) significant spousal correlations of +0·19 and +0·18 for right-hand and left-hand 2D:4D, respectively, and +0·24 for average 2D:4D; (ii) no assortative mating effect on the right-minus-left difference in 2D:4D; (iii) indications consistent with a possible generational decrease of spousal similarity in 2D:4D; (iv) a prevalence of couples with a lower right-hand 2D:4D observed in the husband compared with his wife; and (v) relations of spousal 2D:4D patterns to spousal age differences, such that matings of men with more male-typical trait expressions (namely, a generally low right-hand 2D:4D or showing a lower right-minus-left 2D:4D difference than their wives) implicated larger male-minus-female age differences, i.e. younger wives. It is argued that assortative mating on 2D:4D operates indirectly and may be mediated through the assortment on other, more perceptible, physical traits and psychological phenotypes that entertain associations with 2D:4D and are relevant for courtship and mate choice.

Is ‘best interests’ the right standard in cases like that of Charlie Gard?

2019 ◽  
Vol 46 (1) ◽  
pp. 16-17 ◽  
Author(s):  
Robert D Truog
Keyword(s):  
Harm Principle ◽  
Best Interests ◽  
Clinical Decisions ◽  
Disabled Children ◽  
The Usa ◽  
The Uk ◽  
The Right ◽  
Legal Judgments ◽  
The Harm Principle

Savulescu and colleagues have provided interesting insights into how the UK public view the ‘best interests’ of children like Charlie Gard. But is best interests the right standard for evaluating these types of cases? In the USA, both clinical decisions and legal judgments tend to follow the ‘harm principle’, which holds that parental choices for their children should prevail unless their decisions subject the child to avoidable harm. The case of Charlie Gard, and others like it, show how the USA and the UK have strikingly different approaches for making decisions about the treatment of severely disabled children.

Digit Ratios (2D:4D and other) and Relative Thumb Length: A Test of Developmental Stability

2007 ◽  
Vol 105 (1) ◽  
pp. 143-152 ◽  
Author(s):  
Martin Voracek ◽  
Denise Offenmuller
Keyword(s):  
Young Adults ◽  
Sex Differences ◽  
Developmental Stability ◽  
Digit Ratio ◽  
Childhood And Adolescence ◽  
Finger Length ◽  
Digit Ratios ◽  
Fourth Digit ◽  
Prenatal Androgens ◽  
Length Measurements

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.

scholarly journals Depression Is Associated With the Absence of Sex Differences in the 2D:4D Ratio of the Right Hand

2019 ◽  
Vol 10 ◽  
Author(s):  
Simon Sanwald ◽  
Katharina Widenhorn-Müller ◽  
Jennifer Wernicke ◽  
Cornelia Sindermann ◽  
Markus Kiefer ◽  
...  
Keyword(s):  
Sex Differences ◽  
Right Hand ◽  
The Right

Sex Differences in Directional Asymmetry of Digit Length and its Effects on Sex Differences in Digit Ratio (2D:4D)

2008 ◽  
Vol 107 (2) ◽  
pp. 576-586 ◽  
Author(s):  
Martin Voracek ◽  
Denise Offenmüller ◽  
Stefan G. Dressler
Keyword(s):  
Sex Differences ◽  
Ring Finger ◽  
Digit Ratio ◽  
Directional Asymmetry ◽  
Leftward Bias ◽  
First Finding ◽  
The Right ◽  
Putative Marker ◽  
Prenatal Androgen ◽  
Digit Length

Patterns of directional asymmetry in the length of index and ring finger (2D and 4D) may be sexually differentiated. Martin, Puts, and Breedlove (2008) found leftward bias, i.e., both a longer 2D and 4D in the left than in the right hand, more frequently in men, whereas rightward bias occurred more frequently in women. Further, rightward vs leftward bias seemed a substantial source of variation in digit ratio (2D:4D), a putative marker for prenatal androgen levels. Given the generally small effects, unreplicable results, and inconsistent findings of 2D:4D research, these findings potentially are important as the type of directional digit asymmetry could moderate or obfuscate real associations between 2D:4D and target traits. Based on six samples totaling about 3,000 individuals, the present study replicated the first finding of Martin, Puts, and Breedlove (2008): leftward bias was more frequent among men and rightward bias more frequent among women. This sex effect was small. However, the present study did not replicate the second finding of Martin, et al. (2008): relative to participants' sex the contributions of leftward vs rightward asymmetry to individual variation in 2D:4D were smaller by orders of magnitude and not significant. Implications of these findings for 2D:4D research arc discussed.

scholarly journals Association of Digit Ratio With Depression and Hopelessness in Females

2021 ◽  
Vol 6 (3) ◽  
pp. 100-104
Author(s):  
Shabnam Aliabadi ◽  
Zahra Zendehboodi
Keyword(s):  
Severe Depression ◽  
Study Groups ◽  
Cross Sectional Study ◽  
Digit Ratio ◽  
Cross Sectional ◽  
Right Hand ◽  
Group 2 ◽  
Student’S T ◽  
The Right ◽  
Group 1

Introduction: Depression is regarded as the main cause of individual’s incapacity. One of the component of depression is hopelessness. This study was planned to examine if the digit ratio associates with depression and hopelessness status in the Iranian women. Methods: This cross-sectional study sample included 358 women aged between 20 to 32 years old. The palm side of both hands of individuals was photographed and then the length of index and ring fingers was measured by ImageJ. The Beck’s depression inventory II and Beck’s hopelessness scale (BHS) were used to measure the levels of depression and hopelessness respectively. ANOVA and Student’s t test was applied to compare the study groups in respect to the continuous data. Results: The results showed that the means of 2D:4D ratio of neither right nor left hands were significantly different between the depression study groups. The same insignificant results were derived with hopelessness status too. However, reanalyzing the data, while combination of depression and hopelessness was considered, showed a significantly lower digit ratio of the right hand in the women whit neither depression nor hopelessness (group 1) compared to the women with moderate/severe depression while holding a degree of hopelessness (group 2) (ratio mean for group 1: 0.978 ± 0.003 and for group 2: 0.992 ± 0.005; t = -2.417, P = 0.017). Conclusion: Our data suggested that the 2D:4D ratio of the right hand in the women associates with the severity of depression when accompanied by hopelessness.

Why Does Digit Ratio Research Fail to Give Any Implication Regarding the Organizational Effect of Prenatal Androgen?

2017 ◽  
Vol 38 (1) ◽  
pp. 36-45 ◽  
Author(s):  
Larry Au Yeung ◽  
Wai S. Tse
Keyword(s):  
Sample Size ◽  
Meta Analysis ◽  
Relevant Literature ◽  
Current Data ◽  
Digit Ratio ◽  
Prenatal Testosterone ◽  
Prenatal Hormones ◽  
Inadequate Sample Size ◽  
Current Sample ◽  
The Right

Abstract. The digit ratio is a putative biomarker for evaluating the organizational effects of prenatal testosterone. This evaluation was performed by relating postnatal traits to digit ratio. We examined the relationship among digit ratio, depression, and positive/negative affect. A total of 335 university students who completed a set of questionnaires had both of their hands scanned, and the digit ratios were measured using a computer program. All the studied variables were insignificantly related to the right-hand digit ratio. The variables remained insignificant even when the data for males and females were analyzed separately. Furthermore, a meta-analysis, including a previous study combined with current data, showed no association between digit ratio and depression, although the current sample size of 355 could detect r = 0.2 at α = 0.05, and β = 0.2. The lack of association between digit ratio and depression was common, and the present results corroborated those of previous studies, which showed no association between digit ratio and depression. This nil result would be least likely attributable to an inadequate sample size, considering that the current sample size of 335 allowed the detection of r = 0.2 at α = 0.05 and β = 0.2, nor idiosyncratic results, given that the meta-analysis with previous relevant studies also concluded the same results. We extensively reviewed the relevant literature and evaluated the use of digit ratio as a biomarker for prenatal testosterone exposure in seven different perspectives. Nearly all the analysis showed the problems of using digit ratio as a biomarker for evaluating the organizational effect of prenatal hormones.

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