Contemporary sex differences in partner preferences are maintained by several psycho-biological mechanisms that evolved in conjunction, including not only sexual but also romantic attraction

The Role of Sexual and Romantic Attraction in Human Mate Preferences. Meike Scheller et al. The Journal of Sex Research, Feb 16 2023. https://doi.org/10.1080/00224499.2023.2176811

Abstract: Sex differences in mate preferences are ubiquitous, having been evidenced across generations and cultures. Their prevalence and persistence have compellingly placed them in the evolutionarily adaptive context of sexual selection. However, the psycho-biological mechanisms contributing to their generation and maintenance remain poorly understood. As such a mechanism, sexual attraction is assumed to guide interest, desire, and the affinity toward specific partner features. However, whether sexual attraction can indeed explain sex differences in partner preferences has not been explicitly tested. To better understand how sex and sexual attraction shape mate preferences in humans we assessed how partner preferences differed across the spectrum of sexual attraction in a sample of 479 individuals that identified as asexual, gray-sexual, demisexual or allosexual. We further tested whether romantic attraction predicted preference profiles better than sexual attraction. Our results show that sexual attraction accounts for highly replicable sex differences in mate preferences for high social status and financial prospects, conscientiousness, and intelligence; however, it does not account for the enhanced preference for physical attractiveness expressed by men, which persists even in individuals with low sexual attraction. Instead, sex differences in physical attractiveness preference are better explained by the degree of romantic attraction. Furthermore, effects of sexual attraction on sex differences in partner preferences were grounded in current rather than previous experiences of sexual attraction. Taken together, the results support the idea that contemporary sex differences in partner preferences are maintained by several psycho-biological mechanisms that evolved in conjunction, including not only sexual but also romantic attraction.

Discussion

While sex differences in human mate preferences have been observed across cultures and generations (Buss, Citation1989; Shackelford et al., Citation2005; Walter et al., Citation2020) the proximate factors contributing to its generation and maintenance remain less well understood (but see Alexander et al., Citation2011; Balthazart, Citation2011, Citation2016; Little, Jones et al., Citation2011; Scheller et al., Citation2021). Attraction, especially sexual attraction, is a psycho-biological mechanism that is thought to guide interest, desire or the affinity toward specific features of others and establishes an individual’s preference profile. In order to better understand how sex and sexual attraction interact, and whether other forms of attraction (i.e., romantic) may explain persistent patterns in mate preferences, we assessed how partner preferences differ across the spectrum of sexual attraction intensity.

In individuals that experience high sexual attraction we replicated well-documented sex differences in partner preferences that are linked to sexual reproduction. Here, heterosexual men rated physical attractiveness higher than women, while the latter placed higher importance on social status and financial prospects than men. This is in line with a large body of research showing sex differences in preferences for these traits (Bech-Sørensen & Pollet, Citation2016; Buss, Citation1989; Walter et al., Citation2020). The data-driven nature of the factor composition indicated two further partner characteristic factors that were described as conscientiousness (ambition, emotional stability/maturity, reliability, diligence, humor, and sociability) and intelligence/education (be educated, similar education, intelligence). Here, individuals that experienced high sexual attraction showed significant sex differences in preferences, with women rating conscientiousness as more important, while men gave higher importance ratings for intelligence and education. Indeed, previous studies have found conscientiousness, ambition and emotional stability to be more highly valued by women (Botwin et al., Citation1997; Buss & Schmitt, Citation2019; Furnham, Citation2009); however, the enhanced importance ratings of intelligence and education in allosexual men seem to contradict previous findings in hetero-allosexual samples in which women valued education more than men (Buss & Schmitt, Citation2019; Shackelford et al., Citation2005). Lippa (Citation2007), however, reported that heterosexual women rated intelligence lower than lesbian women and gay men, which may suggest that sexual intensity and orientation may indeed mediate intelligence importance ratings. As women show lower average sexual attraction levels than men and often show higher levels of non-exclusivity in their sexual orientation (e.g., bisexual preferences; Diamond, Citation2016), the effect of diversity in sexual intensity and orientation in women may not have been captured in previous studies, but impacted the absolute importance ratings. However, this would likely have affected all partner characteristics, and future research into the effects of sexual orientation and intensity on the importance of specific partner traits is needed to elucidate whether these effects replicate in a different sample.

Effects of Sexual and Romantic Attraction on Sex Differences in Partner Preferences

Notably, our results show that sexual and romantic attraction both help explain the maintenance of sex-specific mate preference differentiation. Self-reported preferences for all four partner traits were significantly or marginally significantly modulated by sex as well as either sexual or romantic attraction. Furthermore, the results support the notion that both forms of attraction can function independently (Diamond, Citation2003, Citation2004; Fisher et al., Citation2005, Citation2006) and do not affect partner preferences in the same way. While sex-specific differences in preferences for a high social status and good financial prospects (women > men), as well as intelligence and education (men > women) were reduced in individuals with low or no sexual attraction, the increased preferences for a conscientious partner in women was more strongly modulated by romantic than sexual attraction. Surprisingly, the only sex-specific difference that sexual attraction could not account for was the heightened preference for a physically attractive partner in men. Even individuals that reported to have never experienced sexual attraction before showed a sex difference in the preference for this partner trait that was of similar magnitude (β = −0.41) as that present in allosexual individuals (β = −0.39). Instead, sex-specific physical attractiveness preferences were more dependent on the degree of romantic attraction, highlighting the importance of physical attractiveness in romantic contexts. Note that, while the interaction of romantic attraction and sex was only marginally significant (p = .06), effect sizes suggested that the average explanatory power of romantic attraction was 25 times higher than that of sexual attraction.

This suggests that physical attractiveness may serve more functions than providing good genes. In fact, the heightened preference that men express for physical attractiveness even extends outside of the mating context, affecting other social bonds such as friendships. Here, men place more importance than women on physical attractiveness in opposite-sex friends (Lewis et al., Citation2011). Perhaps this is due to the indirect benefit gained from being associated with physically attractive individuals. That is, partnering with a physically attractive woman may enhance the perception of someone’s own social status and mate value, thereby attaching higher chances of partnering with other attractive woman in the long term (C. Anderson et al., Citation2001; R. C. Anderson & Surbey, Citation2014; see supplement S3 for indirect appearance belief effects).

Sexual attraction is not a prerequisite for romantic attraction. In fact, many individuals with reduced sexual desire still experience romantic attraction and look to engage in romantic relationships with others (Antonsen et al., Citation2020). However, the specific preferences for such romantic, non-sexual relationships may differ. For instance, women with low sexual attraction placed more importance on intelligence and education, and less importance on physical attractiveness, status and financial prospects or conscientiousness than women with higher sexual attraction. At the same time, men with low sexual attraction placed less importance on all partner characteristics, except social status and financial prospects, which already received the lowest importance rankings amongst all character traits. Our results show that sex differences in preferences for conscientiousness and physical attractiveness are better explained by romantic attraction, while those in social status/resources and intelligence are better explained by sexual attraction. This pattern may be explained by the types of benefits accrued in different relationship contexts (Buss & Schmitt, Citation1993; Li, Citation2007; Regan et al., Citation2000). For example, although previous research has often noted potential good-gene benefits from short-term partnerships, a long-term romantic relationship with a conscientious and physically attractive partner would provide commitment, investment, and potentially good gene benefits to offspring. Indeed, as romantic attraction is a crucial factor facilitating pair-bonding and (parental) care in monogamous relationships we might also expect that physical attractiveness will be important if there are associated benefits to offspring. Our data may suggest that, if sexual attraction is associated with short term mating (Edlund et al., Citation2021; Li, Citation2007), perhaps the increased preferences for status/resources reflect more material direct benefits from such partnerships.

Furthermore, our data showed that, while sexual and romantic orientation (directionality) were mostly aligned in allosexual individuals, the correlation was markedly lower among those with lower sexual attraction ratings. This divergent sexual and romantic orientation again suggests that sexual attraction and romantic attraction operate independently not only via their intensity but also their orientation (Antonsen et al., Citation2020; Diamond, Citation2004; Tennov, Citation1998).

Limitations

Firstly, the AIS score was used as an indicator of progressively decreasing sexual attraction in the present study. However, it was primarily developed to differentiate those identifying as asexual from those who do not (Yule et al., Citation2015). As the AIS incorporates further measures that go beyond mere sexual attraction (such as sex-related disgust, sexual behavior avoidance, or sexual identity), it captures a wider experience of reduced sexual attraction and interest. In order to ensure that the main feature of interest i.e., reduced sexual attraction, was the modulating factor, we included a second, isolated measure of sexual attraction intensity, along with a measure of romantic attraction intensity. Here, participants were asked to indicate how strongly they felt sexually or romantically attracted to men and to women on a 7-point Likert scale. Comparing our findings from the first analysis using AIS scores and the second analysis using raw sexual attraction intensity scores, we found that results were similar across both analyses: both AIS scores and sexual attraction intensity show no interaction with sex in explaining preferences for physical attractiveness, while they both explain sex differences in the preferences for social status, conscientiousness, and intelligence (note that the inverse coefficients result from low sexual attraction being indicated by high AIS scores). This suggests that, while the AIS score offers a more fine-grained and experience-dependent measure of sexual attraction, desire and interest, sexual attraction alone is a large contributing factor to the expression of specific partner preferences.

Secondly, while sexual attraction is considered here as a psycho-biological mechanism that evolved to maintain partner preferences that adapted to evolutionary reproductive pressures, reduced sexual attraction does not automatically equate to a lowered desire to procreate. That is, individuals with reduced sexual attraction may not seek sexual encounters for pleasure but may still express the desire to have and raise children. If the desire is not reduced, this can suggest that partner preferences in people with reduced sexual attraction may not be targeted at a partner with whom genetic material or resources are exchanged to provide for offspring. Instead, the alteration in partner preferences might be driven by other factors, depending on the function of the partnership. Indeed, previous research suggests that the function of a partnership, such as in short-term or long-term mating, alters mate preferences (Bode & Kushnick, Citation2021; Jonason et al., Citation2013; Li, Citation2007). However, we observed, on average, a reduced desire to have and raise children across sexual orientation groups with low sexual attraction (demi-, gray- and asexuals), compared to individuals with high sexual attraction (see supplement S6). This suggests that reduced sexual desire and reduced desire to have and raise children with a partner may shape the expression of specific partner preferences.