title: Second to fourth digit ratio and face shape.
abstract: The average human male face differs from the average female face in size and shape of the jaws, cheek-bones, lips, eyes and nose. It is possible that this dimorphism is determined by sex steroids such as testosterone (T) and oestrogen (E), and several studies on the perception of such characteristics have been based on this assumption, but those studies focussed mainly on the relationship of male faces with circulating hormone levels; the corresponding biology of the female face remains mainly speculative. This paper is concerned with the relative importance of prenatal T and E levels (assessed via the 2D : 4D finger length ratio, a proxy for the ratio of T/E) and sex in the determination of facial form as characterized by 64 landmark points on facial photographs of 106 Austrians of college age. We found that (i) prenatal sex steroid ratios (in terms of 2D : 4D) and actual chromosomal sex dimorphism operate differently on faces, (ii) 2D : 4D affects male and female face shape by similar patterns, but (iii) is three times more intense in men than in women. There was no evidence that these effects were confounded by allometry or facial asymmetry. Our results suggest that studies on the perception of facial characteristics need to consider differential effects of prenatal hormone exposure and actual chromosomal gender in order to understand how characteristics have come to be rated 'masculine' or 'feminine' and the consequences of these perceptions in terms of mate preferences.
authors.affiliation: Department for Sociobiology/Anthropology, Institute for Zoology & Anthropology, University of Göttingen, Berliner Strasse 28, D-37073 Götingen, Germany. bernhard.fink@ieee.org
authors.forename: Bernhard
authors.initials: B
authors.lastname: Fink
authors.forename: Karl
authors.initials: K
authors.lastname: Grammer
authors.forename: Philipp
authors.initials: P
authors.lastname: Mitteroecker
authors.forename: Philipp
authors.initials: P
authors.lastname: Gunz
authors.forename: Katrin
authors.initials: K
authors.lastname: Schaefer
authors.forename: Fred L
authors.initials: FL
authors.lastname: Bookstein
authors.forename: John T
authors.initials: JT
authors.lastname: Manning
mesh_terms: D000328:Adult; D001317:Austria; D001837:Body Weights and Measures; D005145:Face / Q000033:anatomy & histology*; D005260:Female; D005385:Fingers / Q000033:anatomy & histology*; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D010364:Pattern Recognition, Visual / Q000502:physiology*; D012727:Sex Characteristics
chemical_list: D012739:Gonadal Steroid Hormones