Associations between asymmetry and human attractiveness: Possible direct effects of asymmetry and signatures of publication bias

Abstract

Background: Fluctuating asymmetry (FA), reflecting developmental instability (DI), may honestly signal individual quality and relate to human attractiveness and measures of sexual behaviour. The evolutionary importance of these associations, however, critically depends on the role of DI in driving these correlations. A direct effect of FA reduces the role of DI.

Aim: To explore the direct effects of FA in determining human attractiveness, comparing the strength of associations whether the asymmetries could be observed during the attractiveness ratings or not.

Subjects and methods: Literature search and meta-analysis.

Results: This study found indications for such a direct role through stronger associations between FA and physical attractiveness when asymmetries are visible. Furthermore, a substantial publication bias emerged and correcting for it resulted in a reduction of 30–50% in effect sizes. When considering the few relatively large with sample size over 100 only, effect sizes were nearly zero.

Conclusion: The current literature likely overstates the evolutionary importance of asymmetry in determining human (physical) attractiveness. This study discusses the possible consequences for presumed associations between DI and human sexual behaviour and fitness.

Keywords::

• Fluctuating asymmetry
• developmental instability
• human
• sexual behaviour
• simulation
• repeatability
• attractiveness

Acknowledgements

Two anonymous reviewers provided valuable suggestions to improve this paper.

Declaration of interest: This study was supported by Research program G.0025.07 of the research Foundation-Flanders (FWO). The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.