Relative Finger Lengths, Sex Differences, and Psychological Traits

Various finger length and personality and ability measures were obtained for a sample of Australian adolescent twins (306 boys and 397 girls). A new measure of relative finger length (the length of a given finger relative to the sum of all four fingers) was investigated, and shown to be superior to the traditional 2D:4D for discriminating between the sexes. It also had the advantage of permitting a more analytic approach: for example, the 2nd finger-length contributed much more than the 4th finger length to the sex difference in 2D:4D, and a smooth gradient of sex differences across the hand was evident. Sex differences on right hands were greater than those for left hands. Within-sex correlations were obtained between the various finger-length measures and a personality and an ability scale that showed relatively large sex differences (Eysenck’s Psychoticism scale and the spatial subscale from Jackson’s Multidimensional Aptitude Battery). The correlations were low, but on the whole consistent with the between-sex differences for the girls. For the boys, this was so for Psychoticism, but spatial ability was, if anything, correlated in the opposite direction.

[1]  M. McIntyre,et al.  Reproductive Biology and Endocrinology Open Access the Use of Digit Ratios as Markers for Perinatal Androgen Action , 2022 .

[2]  S. M. Breedlove,et al.  Masculinized Finger Length Patterns in Human Males and Females with Congenital Adrenal Hyperplasia , 2002, Hormones and Behavior.

[3]  Dennis McFadden,et al.  Masculinization Effects in the Auditory System , 2002, Archives of sexual behavior.

[4]  C. Carlson,et al.  Physiological evidence of hypermasculinization in boys with the inattentive type of attention-deficit/hyperactivity disorder (ADHD) , 2005, Clinical Neuroscience Research.

[5]  Robert Tibshirani,et al.  An Introduction to the Bootstrap , 1994 .

[6]  P. Ellison,et al.  Sex dimorphism in digital formulae of children. , 2006, American journal of physical anthropology.

[7]  C. Acerini,et al.  In-utero androgen exposure and 2nd to 4th digit length ratio-comparisons between healthy controls and females with classical congenital adrenal hyperplasia. , 2003, Human reproduction.

[8]  B. Vollenhoven,et al.  Anatomical evidence for in utero androgen exposure in women with polycystic ovary syndrome. , 2005, Fertility and sterility.

[9]  A. Okten,et al.  The ratio of second- and fourth-digit lengths and congenital adrenal hyperplasia due to 21-hydroxylase deficiency. , 2002, Early human development.

[10]  Margaret J. Wright,et al.  Brisbane Adolescent Twin Study: Outline of study methods and research projects , 2004 .

[11]  J T Manning,et al.  The ratio of 2nd to 4th digit length: a predictor of sperm numbers and concentrations of testosterone, luteinizing hormone and oestrogen. , 1998, Human reproduction.

[12]  H. Eysenck,et al.  Psychoticism as a dimension of personality , 1976 .

[13]  Susan D. Voyer,et al.  Magnitude of sex differences in spatial abilities: a meta-analysis and consideration of critical variables. , 1995, Psychological bulletin.

[14]  F. Baker.  ANTHROPOLOGICAL NOTES ON THE HUMAN HAND , 1888 .

[15]  J. Loehlin,et al.  A Reanalysis of Five Studies on Sexual Orientation and the Relative Length of the 2nd and 4th Fingers (the 2D:4D Ratio) , 2005, Archives of sexual behavior.

[16]  J. S. Hunt,et al.  The role of HLA-G in human pregnancy , 2006, Reproductive biology and endocrinology : RB&E.

[17]  M. Voracek,et al.  Lack of correlation between digit ratio (2D:4D) and Baron-Cohen's "Reading the Mind in the Eyes" test, empathy, systemising, and autism-spectrum quotients in a general population sample. , 2006 .

[18]  Rebecca C. Knickmeyer,et al.  2nd to 4th digit ratios, fetal testosterone and estradiol. , 2004, Early human development.

[19]  Jacob Cohen.  Statistical Power Analysis for the Behavioral Sciences , 1969, The SAGE Encyclopedia of Research Design.

[20]  Kevin J. MacKenzie,et al.  Finger length and distal finger extent patterns in humans. , 2002, American journal of physical anthropology.

[21]  Anne C. Petersen,et al.  Physical androgyny and cognitive functioning in adolescence. , 1976 .

[22]  K. Desdicioglu,et al.  Fetal development of the hand, digits and digit ratio (2D:4D). , 2006, Early human development.

[23]  W. Babler,et al.  Early prenatal attainment of adult metacarpal-phalangeal rankings and proportions. , 1975, American journal of physical anthropology.

[24]  Erin Shubel,et al.  Relative Lengths of Fingers and Toes in Human Males and Females , 2002, Hormones and Behavior.

[25]  Sarah E Medland,et al.  Population Differences in Finger-Length Ratios: Ethnicity or Latitude? , 2006, Archives of sexual behavior.

[26]  P. Hurd,et al.  Depression in men is associated with more feminine finger length ratios , 2005 .

[27]  J. Manning.  Digit Ratio: A Pointer to Fertility, Behavior, and Health , 2002 .

[28]  S. Gaulin,et al.  Sex hormones and finger length: What does 2D:4D indicate? , 2004 .

[29]  Hans J. Eysenck,et al.  Manual of the Eysenck personality questionnaire , 1975 .

[30]  Richard A. Lippa,et al.  Finger lengths, 2D:4D ratios, and their relation to gender-related personality traits and the Big Five , 2006, Biological Psychology.

[31]  G. Sanders,et al.  The Ratio of the 2nd to 4th Finger Length Predicts Spatialability in Men but Not Women , 2005, Cortex.

[32]  L. Burton,et al.  Gender Differences in Relations of Mental Rotation, Verbal Fluency, and SAT Scores to Finger Length Ratios as Hormonal Indexes , 2005, Developmental neuropsychology.