The Role of Sexual and Romantic Attraction in Human Mate Preferences.

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.

The Role of Vision in the Emergence of Mate Preferences.

Cross-cultural research has repeatedly demonstrated sex differences in the importance of partner characteristics when choosing a mate. Men typically report higher preferences for younger, more physically attractive women, while women typically place more importance on a partner's status and wealth. As the assessment of such partner characteristics often relies on visual cues, this raises the question whether visual experience is necessary for sex-specific mate preferences to develop. To shed more light onto the emergence of sex differences in mate choice, the current study assessed how preferences for attractiveness, resources, and personality factors differ between sighted and blind individuals using an online questionnaire. We further investigate the role of social factors and sensory cue selection in these sex differences. Our sample consisted of 94 sighted and blind participants with different ages of blindness onset: 19 blind/28 sighted males and 19 blind/28 sighted females. Results replicated well-documented findings in the sighted, with men placing more importance on physical attractiveness and women placing more importance on status and resources. However, while physical attractiveness was less important to blind men, blind women considered physical attractiveness as important as sighted women. The importance of a high status and likeable personality was not influenced by sightedness. Blind individuals considered auditory cues more important than visual cues, while sighted males showed the opposite pattern. Further, relationship status and indirect, social influences were related to preferences. Overall, our findings shed light on the availability of visual information for the emergence of sex differences in mate preference.

Heterogeneity in the Sexual Orientations of Men Who Have Sex with Fa'afafine in Samoa.

In Samoa, feminine natal males who possess male-typical genitalia are known locally as fa'afafine. Some Samoan men express sexual interest in fa'afafine, whereas others do not. To assess the sexual orientation of men who are sexually interested in fa'afafine, we collected sexual attraction ratings and viewing times of Samoan men's and women's faces. Study 1 (N = 130) focused on men who were insertive or versatile during anal sex with fa'afafine partners. These men were compared to each other, as well as to males (i.e., men and fa'afafine) who were exclusively sexually interested in either women or men. Study 2 (N = 180) compared men who had sex with fa'afafine and women; men who had sex with fa'afafine, women, and men; and men who had sex with fa'afafine and men. These men were compared to each other, as well as to males who were exclusively sexually interested in either women or men. These studies suggest that men who have sex with fa'afafine are a heterogeneous group. A small portion of the men who are sexually interested in fa'afafine shows a relatively bisexual pattern of sexual attraction ratings and viewing times, namely men who have sex with fa'afafine, men, and women. In contrast, a larger number of men who were sexually interested in fa'afafine responded in a manner similar to men who were exclusively sexually interested in either women or men. The present research suggests that additional insights into male sexual orientation can be garnered by focusing on how sexuality is expressed in non-Western cultural contexts.

No evidence that women using oral contraceptives have weaker preferences for masculine characteristics in men's faces.

Previous research has suggested that women using oral contraceptives show weaker preferences for masculine men than do women not using oral contraceptives. Such research would be consistent with the hypothesis that steroid hormones influence women's preferences for masculine men. Recent large-scale longitudinal studies, however, have found limited evidence linking steroid hormones to masculinity preferences. Given the relatively small samples used in previous studies investigating putative associations between masculinity preferences and oral contraceptive use, we compared the facial masculinity preferences of women using oral contraceptives and women not using oral contraceptives in a large online sample of 6482 heterosexual women. We found no evidence that women using oral contraceptives had weaker preferences for male facial masculinity than did women not using oral contraceptives. These findings add to a growing literature suggesting that links between reproductive hormones and preferences are more limited than previously proposed.

Mate retention Strategies, Self-Esteem, Mate Value and Facial Attractiveness Disparity in Brazil and in the UK.

This study compared mate retention strategies (MRS) in Brazil and in the UK, testing whether culture moderates the association between MRS and self-evaluated variables (e.g. mate value). Our findings demonstrated that women's MRS varied cross-culturally, with Brazilian women reporting to perform MRS more often than British women. Men's MRS did not vary between cultures. Additionally, culture moderated the association between MRS frequency and facial attractiveness disparity (the difference in attractiveness between partners) and mate value. This study presents initial evidence on the influence of culture on the frequency of MRS and its role in the association between self-evaluation and strategies designed to retain a partner.

Viewing Time and Self-Report Measures of Sexual Attraction in Samoan Cisgender and Transgender Androphilic Males.

Across cultures, androphilic males (natal males who are predominantly sexually attracted to adult men, not women) tend to present in one of two forms: cisgender or transgender. Previous research has shown that, although their gender presentation and identities are distinct, the two forms are similar in many other ways. The present study examined whether cisgender and transgender androphilic males exhibit a similar pattern of self-reported sexual attraction and viewing time response to images of men and women, and one that is directly inverse to that of cisgender gynephilic males (natal males who are predominately sexually attracted to adult women, not men). Using measures of self-reported sexual attraction and viewing time, we compared the response patterns of Samoan cisgender males who self-identified as men, were predominantly attracted to men, and had sex only with men (N = 16) and Samoan transgender males who self-identified as fa'afafine, were predominantly attracted to men, and had sex only with men (N = 30). Samoan cisgender males who self-identified as men, were predominantly attracted to women, and had sex only with women (N = 31) served as a comparison group. Androphilic men and fa'afafine reported greater sexual attraction to men than women and viewed the images of men longer than those of women. Gynephilic men showed the inverse pattern. Viewing time discrepancies between participant's preferred gender and their non-preferred gender were greater for gynephilic men compared to the two androphilic groups. The implications of these preliminary findings for the use of viewing time measures of male sexual orientation across different cultural contexts are discussed.

Average ovarian hormone levels, rather than daily values and their fluctuations, are related to facial preferences among women.

Hormones are of crucial importance for human behavior. Cyclical changes of ovarian hormones throughout women's menstrual cycle are suggested to underlie fluctuation in masculinity preference for both faces and bodies. In this study we tested this hypothesis based on daily measurements of estradiol and progesterone throughout menstrual cycle, and multiple measurements of women's preference towards masculinity of faces and bodies of men. We expected that due to a large variation among daily hormonal levels we would not observe a direct effect of daily hormone levels, but rather that average levels of ovarian hormones throughout the cycle (a reliable marker of a probability of conception) would better predict women's preferences. We found a negative relationship between average progesterone levels and facial masculinity preference, but only among women who were in long-term relationships. There was no relationship between facial masculinity preference and either of the estradiol or progesterone daily levels. Similarly, only average levels of hormones were significantly related to facial symmetry preference. For women who were in relationships estradiol was positively related to symmetry preference, while for single women this relationship was opposite. For body masculinity preference there were no significant relationships with neither averaged nor daily hormonal levels. Taken together, our results further suggest that overall cycle levels of ovarian hormones (averaged for a cycle) are better predictors of facial masculinity and symmetry preference than daily levels assessed during preferences' tests. Importantly, including information about relationship status in the investigations of hormonal bases of preferences is crucial.

No Compelling Evidence that Preferences for Facial Masculinity Track Changes in Women's Hormonal Status.

Although widely cited as strong evidence that sexual selection has shaped human facial-attractiveness judgments, findings suggesting that women's preferences for masculine characteristics in men's faces are related to women's hormonal status are equivocal and controversial. Consequently, we conducted the largest-ever longitudinal study of the hormonal correlates of women's preferences for facial masculinity ( N = 584). Analyses showed no compelling evidence that preferences for facial masculinity were related to changes in women's salivary steroid hormone levels. Furthermore, both within-subjects and between-subjects comparisons showed no evidence that oral contraceptive use decreased masculinity preferences. However, women generally preferred masculinized over feminized versions of men's faces, particularly when assessing men's attractiveness for short-term, rather than long-term, relationships. Our results do not support the hypothesized link between women's preferences for facial masculinity and their hormonal status.

Costs of reproduction are reflected in women's faces: Post-menopausal women with fewer children are perceived as more attractive, healthier and younger than women with more children.

OBJECTIVES: The costs associated with reproduction (i.e., gestation, lactation, childcare) have long-term negative consequences by elevating risk of disease and reducing lifespan. We tested the hypotheses that high parity, and thus high reproductive costs bear by women, is perceived by other people when they evaluate facial appearance of health, attractiveness and age of mothers. MATERIALS AND METHODS: Using computer software we created average facial images based on real photographs of post-menopausal women with varying number of children; 3 parity categories were created (1-2, 4-5, and 7-9 children). Study participants (N = 571) were asked to choose the face they perceived as more attractive, younger and healthier via two-alternative forced choice questions asked in three randomized blocks. RESULTS: Women who had given birth to fewer children were judged both by men and women as more attractive, younger and healthier than women with more children. In each category the lowest scores were received by women from highest parity category (7-9 children). DISCUSSION: Mechanisms behind the observed variation in facial appearance are not known but higher levels of oxidative stress among women with high parity may explain their faster aging and lower attractiveness in older age. These results suggest that costs of reproduction might affect women's physical appearance.

Perceived differences in social status between speaker and listener affect the speaker's vocal characteristics.

Non-verbal behaviours, including voice characteristics during speech, are an important way to communicate social status. Research suggests that individuals can obtain high social status through dominance (using force and intimidation) or through prestige (by being knowledgeable and skilful). However, little is known regarding differences in the vocal behaviour of men and women in response to dominant and prestigious individuals. Here, we tested within-subject differences in vocal parameters of interviewees during simulated job interviews with dominant, prestigious, and neutral employers (targets), while responding to questions which were classified as introductory, personal, and interpersonal. We found that vocal modulations were apparent between responses to the neutral and high-status targets, with participants, especially those who perceived themselves as low in dominance, increasing fundamental frequency (F0) in response to the dominant and prestigious targets relative to the neutral target. Self-perceived prestige, however, was less related to contextual vocal modulations than self-perceived dominance. Finally, we found that differences in the context of the interview questions participants were asked to respond to (introductory, personal, interpersonal), also affected their vocal parameters, being more prominent in responses to personal and interpersonal questions. Overall, our results suggest that people adjust their vocal parameters according to the perceived social status of the listener as well as their own self-perceived social status.

An evolutionary approach to accuracy in social perception.

An evolutionary approach highlights that accuracy should be expected over error because selection pressures will have shaped social perception to be functional. Behaviour is extremely complex and so it is unlikely that observers will be perfectly accurate, but an evolutionary view strongly predicts that people will behave as rational observers and in many cases social perception should favour adaptive responses.

Evolutionary explanations for financial and prosocial biases: Beyond mating motivation.

Mating motivation likely plays a role in bias to attractive individuals, but there are other complementary theories drawn from the evolutionary literature related to competition, friendship, and leadership selection that also make relevant predictions concerning biases towards attractive individuals. The relative balance of these factors will be context dependent and so help explain why the pattern of bias is sometimes variable.

Are there vocal cues to human developmental stability? Relationships between facial fluctuating asymmetry and voice attractiveness.

Fluctuating asymmetry (FA), deviation from perfect bilateral symmetry, is thought to reflect an organism's relative inability to maintain stable morphological development in the face of environmental and genetic stressors. Previous research has documented negative relationships between FA and attractiveness judgments in humans, but scant research has explored relationships between the human voice and this putative marker of genetic quality in either sex. Only one study (and in women only) has explored relationships between vocal attractiveness and asymmetry of the face, a feature-rich trait space central in prior work on human genetic quality and mate choice. We therefore examined this relationship in three studies comprising 231 men and 240 women from two Western samples as well as Hadza hunter-gatherers of Tanzania. Voice recordings were collected and rated for attractiveness, and FA was computed from two-dimensional facial images as well as, for a subset of men, three-dimensional facial scans. Through meta-analysis of our results and those of prior studies, we found a negative association between FA and vocal attractiveness that was highly robust and statistically significant whether we included effect sizes from previously published work, or only those from the present research, and regardless of the inclusion of any individual sample or method of assessing FA (e.g., facial or limb FA). Weighted mean correlations between FA and vocal attractiveness across studies were -.23 for men and -.29 for women. This research thus offers strong support for the hypothesis that voices provide cues to genetic quality in humans.

Effect of Partnership Status on Preferences for Facial Self-Resemblance.

Self-resemblance has been found to have a context-dependent effect when expressing preferences for faces. Whereas dissimilarity preference during mate choice in animals is often explained as an evolutionary adaptation to increase heterozygosity of offspring, self-resemblance can be also favored in humans, reflecting, e.g., preference for kinship cues. We performed two studies, using transformations of facial photographs to manipulate levels of resemblance with the rater, to examine the influence of self-resemblance in single vs. coupled individuals. Raters assessed facial attractiveness of other-sex and same-sex photographs according to both short-term and long-term relationship contexts. We found a preference for dissimilarity of other-sex and same-sex faces in single individuals, but no effect of self-resemblance in coupled raters. No effect of sex of participant or short-term vs. long-term attractiveness rating was observed. The results support the evolutionary interpretation that dissimilarity of other-sex faces is preferred by uncoupled individuals as an adaptive mechanism to avoid inbreeding. In contrast, lower dissimilarity preference of other-sex faces in coupled individuals may reflect suppressed attention to attractiveness cues in potential alternative partners as a relationship maintenance mechanism, and its substitution by attention to cues of kinship and psychological similarity connected with greater likelihood of prosocial behavior acquisition from such persons.

Sex Differences in the Perceived Dominance and Prestige of Women With and Without Cosmetics.

Women wearing cosmetics have been associated with a higher earning potential and higher status jobs. However, recent literature suggests that status can be accrued through two distinct routes: dominance and prestige. In two experiments, we applied a standardized amount of cosmetics to female faces using computer software. We then asked participants to rate faces with and without cosmetics for various traits including attractiveness, dominance, and prestige. Men and women both rated the faces with cosmetics added as higher in attractiveness. However, only women rated faces with cosmetics as higher in dominance, while only men rated them as higher in prestige. In a follow-up study, we investigated whether these enhanced perceptions of dominance from women were caused by jealousy. We found that women experience more jealousy toward women with cosmetics, and view these women as more attractive to men and more promiscuous. Our findings suggest that cosmetics may function as an extended phenotype and can alter other's perceptions differently depending on the perceiver's sex.

Vocal fundamental and formant frequencies affect perceptions of speaker cooperativeness.

In recent years, the perception of social traits in faces and voices has received much attention. Facial and vocal masculinity are linked to perceptions of trustworthiness; however, while feminine faces are generally considered to be trustworthy, vocal trustworthiness is associated with masculinized vocal features. Vocal traits such as pitch and formants have previously been associated with perceived social traits such as trustworthiness and dominance, but the link between these measurements and perceptions of cooperativeness have yet to be examined. In Experiment 1, cooperativeness ratings of male and female voices were examined against four vocal measurements: fundamental frequency (F0), pitch variation (F0-SD), formant dispersion (Df), and formant position (Pf). Feminine pitch traits (F0 and F0-SD) and masculine formant traits (Df and Pf) were associated with higher cooperativeness ratings. In Experiment 2, manipulated voices with feminized F0 were found to be more cooperative than voices with masculinized F0(,) among both male and female speakers, confirming our results from Experiment 1. Feminine pitch qualities may indicate an individual who is friendly and non-threatening, while masculine formant qualities may reflect an individual that is socially dominant or prestigious, and the perception of these associated traits may influence the perceived cooperativeness of the speakers.

The varying value of a friendly face: Experimentally induced stress is associated with higher preferences for friendship with people possessing feminine versus masculine face traits.

Social support can provide a buffer to the negative consequences of stress. Previous research suggests that stress can promote affiliative and cooperative behaviours in those who are stressed. Here we examined how stress might influence who we choose to affiliate with. We measured preferences for friendships with friendly appearing feminized faces versus less friendly appearing masculinized faces after individuals undertook a stressful laboratory task. Stressed individuals had increased preferences for friendships with people with feminine faces. These data demonstrate that individuals prefer more friendly appearing feminine faced people as friends when stressed than when not stressed. This preference is likely adaptive in directing individuals towards others who are most likely to provide social support when it is needed and so reflect strategic friendship preferences.

Face adaptation in an isolated population of African hunter-gatherers: Exposure influences perception of other-ethnicity faces more than own-ethnicity faces.

Previous experiments have demonstrated that exposure to faces can change the perception of normality in new faces, such that faces similar to those at exposure appear more normal. Here we examined how experience influences adaptation effects in African Hadza hunter-gatherers, who have limited experience with White faces. We exposed participants to sets of either Hadza or White European faces that were manipulated to possess either wide-spaced or narrow-spaced eyes. We collected normality judgments both pre-exposure and post-exposure by showing pairs of images, one with wide-spaced and one with narrow-spaced eyes. Examining the difference between the pre-exposure and post-exposure judgments revealed that participants selected an increased number of images that were congruent with the faces to which they had been exposed. The change in normality judgments was strongest for White faces, suggesting that representations of White ethnicity faces are more malleable and less robust to adaptation, potentially because of the decreased experience that individuals had with them. A second experiment using the same test stimuli with a sample of White participants revealed equivalent adaptation effects for both Hadza and White faces. These data highlight the role of experience on the high-level visual adaptation of faces.

Facial coloration tracks changes in women's estradiol.

Red facial coloration is an important social cue in many primate species, including humans. In such species, the vasodilatory effects of estradiol may cause red facial coloration to change systematically during females' ovarian cycle. Although increased red facial coloration during estrus has been observed in female mandrills (Mandrillus sphinx) and rhesus macaques (Macaca mulatta), evidence linking primate facial color changes directly to changes in measured estradiol is lacking. Addressing this issue, we used a longitudinal design to demonstrate that red facial coloration tracks within-subject changes in women's estradiol, but not within-subject changes in women's progesterone or estradiol-to-progesterone ratio. Moreover, the relationship between estradiol and facial redness was observed in two independent samples of women (N = 50 and N = 65). Our results suggest that changes in facial coloration may provide cues of women's fertility and present the first evidence for a direct link between estradiol and female facial redness in a primate species.

Viewing time measures of sexual orientation in Samoan cisgender men who engage in sexual interactions with fa'afafine.

Androphilia refers to attraction to adult males, whereas gynephilia refers to attraction to adult females. The current study employed self-report and viewing time (response time latency) measures of sexual attraction to determine the sexual orientation of Samoan cisgender men (i.e., males whose gender presentation and identity is concordant with their biological sex) who engage in sexual interactions with transgender male androphiles (known locally as fa'afafine) compared to: (1) Samoan cisgender men who only engage in sexual interactions with women, and (2) fa'afafine. As expected, both measures indicated that cisgender men who only engaged in sexual interactions with women exhibited a gynephilic pattern of sexual attraction, whereas fa'afafine exhibited an androphilic one. In contrast, both measures indicated that cisgender men who engaged in sexual interactions with fa'afafine demonstrated a bisexual pattern of sexual attraction. Most of the cisgender men who exhibited bisexual viewing times did not engage in sexual activity with both men and women indicating that the manner in which bisexual patterns of sexual attraction manifest behaviorally vary from one culture to the next.