Influence of sex, sexual orientation, and hormonal cycles on attraction preferences of facial masculinity, femininity, and sex typicality

The present thesis investigated the influences of a person's sex, sexual orientation, and hormonal cycles on attraction preferences for facial masculinity and femininity and sex typicality. It explores whether there are evolutionary adaptive mechanisms involved in attraction preferences across sex and sexual orientation and whether these adaptive mechanisms are influenced by fertility (for women) and testosterone (for men). Chapter 1 gives a general overview of the literature and introduces the research questions. Chapter 2 focuses on whether similarities, or opposites, attract in terms of masculinity-femininity, or whether there is a preference for a match in sex-typicality across sex and sexual orientation. Study 1 uses 3D computer generated images to re-investigate these questions. Study 2 uses real-life computer manipulated images to re-investigate these questions and to counteract the limitations of Study 1. Findings from Study 1 and Study 2 suggest potential evidence for opposite attract, e.g., masculine men prefer feminine female faces, but this evidence was limited. Chapter 3 focuses on whether there is an evolutionary adaptive shift in women’s attraction preferences across fertility levels or whether this shift is dependent on sexual orientation. Findings suggest no compelling evidence for the influence of fertility or sexual orientation on women’s attraction preferences for target sex typicality. Chapter 4 focuses on whether there is an evolutionary adaptive shift in men’s attraction preferences across testosterone levels or whether this shift is dependent on sexual orientation. Findings suggest no compelling evidence for the influence of testosterone or sexual orientation on men’s attraction preferences for target sex typicality. Overall, there is no compelling evidence for evolutionary adaptive shifts in attraction preferences for facial sex-typicality in targets across sex, nor for shifts being dependent of sexual orientation, and no evidence that these mechanisms are influenced by hormonal changes.