UNIVERSITY OF VIENNA - DEPARTMENT OF ANTHROPOLOGY

DEPARTMENT OF ANTHROPOLOGY- HUMAN BEHAVIOR RESEARCH | face and body

Second to fourth digit ratio and face shape

Bernhard Fink ^A1, Karl Grammer ^A2, Philipp Mitteroecker ^A3, Philipp Gunz ^A3, Katrin Schaefer ^A3, Fred L. Bookstein ^A3, John T. Manning ^A4

^A1 Department for Sociobiology/Anthropology, Institute for Zoology & Anthropology, University of Götingen, Berliner Strasse 28, D-37073 Götingen, Germany
^A2 Ludwig-Boltzmann-Institute for Urban Ethology, Althanstrasse 14, A-1090 Vienna, Austria
^A3 Department for Anthropology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
^A4 Department of Psychology, University of Central Lancashire, Preston PR1 2HE, UK

Proceedings of the Royal Society B 272, 1995-2001.

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.

Visualization of the results from an earlier version of the project. On the left the shape regression on female 2D4D and right the corresponding shape regression on male 2D4D. The picture in the middle is the unisex average face.

UNIVERSITY OF VIENNA