Information conveyed by facial attractiveness markers such as averageness, bilateral symmetry, and secondary sexual characteristics may play an important adaptive role in human sexual selection. Nonetheless, mate choice also relies on other non-physical characteristics such as, for instance, an individual's age. Women prefer and enter in relationships with older partners, whereas in men the inverse relation is observed. Surprisingly, the link between facial morphological markers of biological quality on the one hand and age disparity between partners on the other hand has been as yet subject of very little research. This study aims to fill this gap. We had used facial photographs and demographic data of heterosexual marriages. Facial cues of biological quality, such as averageness, bilateral symmetry, and sexual dimorphism, were digitally measured using geometric morphometric methods and then associated with spouses' age difference. It turned out that a greater age disparity between spouses correlates, in both partners, with higher scores in facial measures which indicate partners' biological quality. One exception is female facial masculinity - generally regarded as an unattractive marker of a low biological quality - which, too, is associated with higher spouse age disparity. In general, our results show that facial symmetry, averageness, and secondary sexual characteristics may play a role in age-dependent mate choice. We suggest that in marriages where the wife is considerably younger than the husband, wife's greater facial masculinity may increase her perceived age and with it, her perceived maturity.

Department of Heart Diseases Wroclaw Medical University Weigla 5 50 981 Wroclaw Poland

Department of Philosophy and History of Sciences Faculty of Sciences Charles University Prague Viničná 7 128 44 Praha 2 Czech Republic

Polish Academy of Sciences Anthropology Unit in Wroclaw Podwale 75 50 449 Wroclaw Poland

References provided by Crossref.org

Perceived attractiveness of Czech faces across 10 cultures: Associations with sexual shape dimorphism, averageness, fluctuating asymmetry, and eye color

Toward a New Approach to Cross-Cultural Distinctiveness and Typicality of Human Faces: The Cross-Group Typicality/ Distinctiveness Metric

The Bogazici face database: Standardized photographs of Turkish faces with supporting materials