Effects of sexual dimorphism on facial attractiveness
Authors: S Yoshikawa
S Akamatsu
D M Burt
D Rowland
D I Perrett
I Penton-Voak
S P Henzi
K J Lee
D L Castles
Journal: Nature (1998)
Discipline: Multidisciplinary
Keywords: Testosterone; secondary sexual characteristics; immunological competence; oestrogen; female body
Affiliations: School of Psychology, University of St Andrews, Fife, UK. 

Abstract:  Testosterone-dependent secondary sexual characteristics in males may signal immunological competence and are sexually selected for in several species. In humans, oestrogen-dependent characteristics of the female body correlate with health and reproductive fitness and are found attractive. Enhancing the sexual dimorphism of human faces should raise attractiveness by enhancing sex-hormone-related cues to youth and fertility in females, and to dominance and immunocompetence in males. Here we report the results of asking subjects to choose the most attractive faces from continua that enhanced or diminished differences between the average shape of female and male faces. As predicted, subjects preferred feminized to average shapes of a female face. This preference applied across UK and Japanese populations but was stronger for within-population judgements, which indicates that attractiveness cues are learned. Subjects preferred feminized to average or masculinized shapes of a male face. Enhancing masculine facial characteristics increased both perceived dominance and negative attributions (for example, coldness or dishonesty) relevant to relationships and paternal investment. These results indicate a selection pressure that limits sexual dimorphism and encourages neoteny in humans. 

Retracted: No

PubPeer comments:
 I m intrigued by the references to u201cmasculinizationu201d and u201cfeminizationu201d of faces in research (see my previous comment on this site https: pubpeer.com publications B89ACED5EDD65AA2D1F9AC723E39F9). The terms are never defined explicitly, i.e. with reference to feature or proportion, but rather, implicitly, by reference to method: u201cSexual dimorphism in face shape can then be enhanced or diminished (Perrett et al, 1994; Rowland and Perrett (1995). The two latter reference don t provide answers to the questions of what, in objective terms, is meant by u201cmasculinizationu201d and u201cfeminizationu201d and how or if the method used has been validated. (I m not sure the second question can be answered without clarifying the first). Perrett et al (1994) do not manipulate faces along the u201cmasculineu201d u201cfeminineu201d dimension, so this reference was of no help. Rowland and Perrett (1995) apply a procedure which they claim to alter the masculine of feminine character of faces, but this is based on the premise that a. there are invariants between male and female faces and b. that these may be captured by manipulating a set of u201clandmarks in the 2D image, which are chosen  following previous conventions (notably Brennan(3)). The Brennan reference is to an article in the journal u201cLeonardou201d in which u201cThe author has researched and developed a theory of computation for caricature and has implemented this theory as an interactive computer graphics program.u201d Was the theory ever tested? Do all 2D photos of female faces (or female faces in general) contain certain invariants that don t overlap with those of male faces? Given the vast variety of facial structures, I would be at a loss to guess what these might be. Naturally, given a small set of photos, one might find such a selection of traits, but these are unlikely to generalize. Rowland and Perrett themselves caution us that u201cWe must be wary though that the chosen trait is  real (that is, physically apparent).Francis Galton9 created the notion of a prototypical photographic image by applying thetechniques of composite portraiture to various groups of faces. In one example, he tried tocreate a prototype from  criminal types, perhaps hoping to save the police a lot of time in their inquiries! To his surprise, the resulting composite image was not fundamentally different from composites created by  blending other segments of the community.u201d No citations are offered to substantiate the assumption that the manipulations of Perrett et al (1998) are  real or achieve the desired variation along either an objective dimension (which has not been described) or a subjective dimension (which would require testing and would most likely be inadequate to achieve any type of precision vis a vis a u201cmasculineu201d u201cfeminineu201d facial dimension. Given the above, u201cmasculinizationu201d and u201cfeminizationu201d of faces seem to be words without objective or subjective meaning, and I personally don t feel this popular method to be a good choice for research in this area. ,