Female Orgasm as a Mate-Choice Cue - Testing Hypothesis about Its Evolutionary Function

Abstract

The female orgasm has been the subject of intense debate within evolutionary psychology due to the lack of consensus in the literature regarding its adaptive function. Some of the hypotheses for its possible function consider it as a tool for mate-choice associated with reproductive strategies. Evolutionary theories suggest that women who adopt short-term strategies, may have more orgasms with partners who possess advantageous genetic characteristics for reproduction (sire-choice), while women who adopt long-term strategies would have more orgasms with partners who demonstrate greater emotional bond and parental care (pair-bond). Studies show that homosexual women have a higher frequency of orgasm compared to heterosexual women. If the mate-choice theory is correct, the partners of homosexual women may have advantageous characteristics associated with orgasm. The present thesis investigated the relationship between female orgasm and partner selection, seeking to understand whether the orgasm can be considered an adaptive tool for mate-choice. Based on evolutionary and adaptationist theories, the aim was to explore whether female orgasm can assist in sire-choice and pair-bond strategies. We proposed hypotheses that women with a focus on sire-choice would have more orgasms with partners perceived as healthier, physically attractive, masculine, and dominant, while those with an emphasis on pair-bond would tend to have more orgasms with partners who possess greater financial resources, kindness, empathy, femininity, and intelligence. The present study used three main instruments to collect data. The Marital Empathy Questionnaire (MEQ), which was employed to assess perceived empathy within the participants' relationships. The Female Sexual Function Index (FSFI), and the measurement variable for the orgasm was the score in the orgasm domain. The participants answered the block of characteristics of the sexual partner, which assessed seven traits: Kindness, Intelligence, Health, Physical Attractiveness, Financial Perspective, Femininity-Masculinity, and Dominance. Participants attributed scores from -3 to +3 for each trait, indicating the degree to which they perceived their partners as possessing these characteristics. The research involved the participation of 2785 women, of which 1346 completed all the questionnaires. The final analysis was conducted with 939 sexually active women in committed relationships. The average age of the participants was 28.3 years, and the majority were in a relationship with a male partner (90%). In terms of race/ethnicity, most participants identified as White (68.5%) or Mixed (22.8%). The majority of the sample (70.7%) had at least a university degree, and geographically, the largest proportion of participants was from the Southeast region of Brazil (54.6%). The data analysis used structural equation models (SEM), where the score in the orgasm domain of the FSFI predicted the characteristics of the sexual partner and the duration of the relationship. The same models were applied to participants in both homosexual and heterosexual relationships. Each model tested specific aspects of invariance among women in homosexual and heterosexual relationships. The results showed that women in both types of relationships did not differ statistically in terms of the mean and standard deviation of the orgasm domain and the strength of its relationship with partner characteristics. The analyses indicated that higher orgasm scores were associated with perceptions of greater kindness, intelligence, health, physical attractiveness, and empathy in partners. However, the effect sizes were low, suggesting that although the associations were statistically significant, the practical significance of these findings is limited. Studies on mate-choice and female orgasm have presented similar results, indicating that evidence for the adaptive function of female orgasm is fragile or non-existent. This situation has not undergone significant changes since 2005. Given the complexity of the female orgasm and its underlying structures, we consider two hypotheses regarding the function of female orgasm: (1) as a provider of additional information about the partner and a reinforcer for the maintenance of the relationship, and (2) as a possible ancestral function to allow reflexive or partner-induced ovulation. Reflexive ovulation would enable the assessment of partner quality, so that the ovule would not be released indiscriminately. Therefore, the fact that we find weak effects of orgasm on partner characteristics would be a remnant of the ancestral function that was lost with the emergence of spontaneous ovulation.