Salivary cortisol and pathogen disgust predict men's preferences for feminine shape cues in women's faces

Dual Mating Strategies Observed in Male Clients of Female Sex Workers

Humans have a complex and dynamic mating system, and there is evidence that our modern sexual preferences stem from evolutionary pressures. In the current paper we explore male use of a dual mating strategy: simultaneously pursuing both a long-term relationship (pair-bonding) as well as short-term, extra-pair copulations (variety-seeking). The primary constraint on such sexual pursuits is partner preferences, which can limit male behavior and hence cloud inferences about male preferences. The aim of this study was to investigate heterosexual male mating preferences when largely unconstrained by female partner preferences. In service of this goal, female full-service sex workers (N = 6) were surveyed on the traits and behaviors of their male clients (N = 516) and iterative cluster analysis was used to identify male mating typologies. Two clusters emerged: clients seeking a pair-bonding experience and clients seeking a variety experience. Results also suggested that romantically committed men were more likely to seek a variety experience than a relationship experience. We conclude that men desire both pair-bonding and sexual variety, and that their preference for one might be predicted by fulfilment of the other. These findings have implications for relationships, providing insight into motivations for male infidelity.

Self-perceived Mate Value is Predicted by Biological and self-reported Indices of Health in Young Adults

Immunocompetence can influence an organism's reproductive fitness, and thus presumably their desirability as a mate (i.e., mate value). In humans, the link between immunocompetence and mate value has found circumstantial support by way of both expressed mate preferences for healthy partners, and via preferences for attractive phenotypes that are ostensibly linked to immune functioning. We examined whether a biological marker of immunocompetence, salivary immunoglobulin A (sIgA), along with self-reported frequency and severity of symptoms of poor health predicted individuals' reported mate value and mating behavior in a sample of 691 young adults. Our measures of immunocompetence (sIgA and symptoms of poor health) correlated significantly with one another, suggesting sIgA is a viable marker of general immune function in young adults. We then examined the independent contributions of these variables to mate value, controlling for age, sex, and body mass index (BMI). Results showed that sIgA (positively) and poor health (negatively) predicted mate value, but not lifetime number of sex partners or current romantic relationship status. These findings suggest that those with better health and immune function report being more desirable as mating partners but support past research showing null links to reported mating behavior. Together, these findings suggest that more comprehensive work on links between immunocompetence and mating is required.

Dependents as Signals of Mate Value: Long-term Mating Strategy Predicts Displays on Online Dating Profiles for Men

Sexual strategies theory indicates women prefer mates who show the ability and willingness to invest in a long-term mate due to asymmetries in obligate parental care of children. Consequently, women's potential mates must show they can provide investment - especially when women are seeking a long-term mate. Investment may be exhibited through financial and social status, and the ability to care for a mate and any resulting offspring. Men who care for children and pets (hereafter "dependents") are perceived as high-quality mates, given that dependents signal an ability to invest; however, no studies have examined how dependents are associated with short-term and long-term mating strategies. Here, online dating profiles were used to test the predictions that an interactive effect between sex and mating strategy will predict displays of dependents, with long-term mating strategy predicting for men but not women. Moreover, this pattern should hold for all dependent types and, due to relative asymmetries in required investment, differences will be strongest regarding displays of children and least in non-canine pets. As expected, men seeking long-term mates displayed dependents more than men seeking short-term mates, but both men and women seeking long-term mates displayed dependents similarly. This pattern was driven mostly by canines. These findings indicate that men adopting a long-term mating strategy display their investment capabilities more compared to those seeking short-term mates, which may be used to signal their mate value.

Infection threat shapes our social instincts

We social animals must balance the need to avoid infections with the need to interact with conspecifics. To that end we have evolved, alongside our physiological immune system, a suite of behaviors devised to deal with potentially contagious individuals. Focusing mostly on humans, the current review describes the design and biological innards of this behavioral immune system, laying out how infection threat shapes sociality and sociality shapes infection threat. The paper shows how the danger of contagion is detected and posted to the brain; how it affects individuals’ mate choice and sex life; why it strengthens ties within groups but severs those between them, leading to hostility toward anyone who looks, smells, or behaves unusually; and how it permeates the foundation of our moral and political views. This system was already in place when agriculture and animal domestication set off a massive increase in our population density, personal connections, and interaction with other species, amplifying enormously the spread of disease. Alas, pandemics such as COVID-19 not only are a disaster for public health, but, by rousing millions of behavioral immune systems, could prove a threat to harmonious cohabitation too.

Concern About Contracting COVID-19 Predicts Men's Preference for Female Facial Femininity, But Not Women's Preference for Male Facial Masculinity

Objectives

Humans have evolved a behavioral system that responds to perceptual cues suggesting the existence of a pathogenic threat in other individuals and the environment. While previous investigations have reported that individuals’ sexual preferences are influenced by a pathogen threat, the empirical support for face preference is mixed (i.e., the association of pathogenic threat and individuals’ preferences for masculine and/or feminine faces is equivocal). The COVID-19 pandemic provides the opportunity to investigate the association of pathogenic threat and men’s and women’s preferences for sexual dimorphism of faces in the opposite sex in a real-world pathogenic situation.

Methods

Data were collected during COVID-19 pandemic (March 2020) from men and women in the United States, and women in Iran, on preferences for masculinity in men’s faces using women participants, and femininity in women’s faces using men.

Results

Results showed that concern about an actual pathogenic threat (i.e., contracting COVID-19) predicts men’s preference for female facial femininity, but not women’s preference for male facial masculinity (for both U.S. and Iranian women).

Conclusion

By using an actual pathogenic threat, our results support previous findings that men’s preferences for female faces are shifted to less feminine faces under pathogenic threat. Moreover, our results provide support for the distinction between the behavioral immune system and pathogen disgust, at least for men’s preference for feminine female faces.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40750-020-00158-w.

Biological Bases of Beauty Revisited: The Effect of Symmetry, Averageness, and Sexual Dimorphism on Female Facial Attractiveness

The factors influencing human female facial attractiveness—symmetry, averageness, and sexual dimorphism—have been extensively studied. However, recent studies, using improved methodologies, have called into question their evolutionary utility and links with life history. The current studies use a range of approaches to quantify how important these factors actually are in perceiving attractiveness, through the use of novel statistical analyses and by addressing methodological weaknesses in the literature. Study One examines how manipulations of symmetry, averageness, femininity, and masculinity affect attractiveness using a two-alternative forced choice task, finding that increased masculinity and also femininity decrease attractiveness, compared to unmanipulated faces. Symmetry and averageness yielded a small and large effect, respectively. Study Two utilises a naturalistic ratings paradigm, finding similar effects of averageness and masculinity as Study One but no effects of symmetry and femininity on attractiveness. Study Three applies geometric face measurements of the factors and a random forest machine learning algorithm to predict perceived attractiveness, finding that shape averageness, dimorphism, and skin texture symmetry are useful features capable of relatively accurate predictions, while shape symmetry is uninformative. However, the factors do not explain as much variance in attractiveness as the literature suggests. The implications for future research on attractiveness are discussed.

Facial Adiposity, Attractiveness, and Health: A Review

The relationship between facial cues and perceptions of health and attractiveness in others plays an influential role in our social interactions and mating behaviors. Several facial cues have historically been investigated in this regard, with facial adiposity being the newest addition. Evidence is mounting that a robust link exists between facial adiposity and attractiveness, as well as perceived health. Facial adiposity has also been linked to various health outcomes such as cardiovascular disease, respiratory disease, blood pressure, immune function, diabetes, arthritis, oxidative stress, hormones, and mental health. Though recent advances in the analysis of facial morphology has led to significant strides in the description and quantification of facial cues, it is becoming increasingly clear that there is a great deal of nuance in the way that humans use and integrate facial cues to form coherent social or health judgments of others. This paper serves as a review of the current literature on the relationship between facial adiposity, attractiveness, and health. A key component in utilizing facial adiposity as a cue to health and attractiveness perceptions is that people need to be able to estimate body mass from facial cues. To estimate the strength of the relationship between perceived facial adiposity and body mass, a meta-analysis was conducted on studies that quantified the relationship between perceived facial adiposity and BMI/percentage body fat. Summary effect size estimates indicate that participants could reliably estimate BMI from facial cues alone (r = 0.71, n = 458).

Adversity-driven changes in hypothalamic-pituitary-adrenal axis functioning during adolescence. The trails study

The hypothalamic-pituitary-adrenal (HPA) axis has been proposed to be a key mechanism underlying the link between adversity and mental health, but longitudinal studies on adversity and HPA-axis functioning are scarce. Here, we studied adversity-driven changes in HPA-axis functioning during adolescence (N=141). HPA-axis functioning (basal cortisol, cortisol awakening response, anticipation of, reaction to and recovery after a stress task) was measured twice, at age 16 and 19. Adversity (i.e., social defeat and loss/illness) since age 16 was measured extensively with the Life Stress Interview at age 19. Adolescents who reported being exposed to social defeat showed increases in basal cortisol (ɳ²=0.029) and decreases in reaction to the stress task (ɳ²=0.030) from age 16-19, compared to their peers in the loss/illness and no stress group. The current study provides unique longitudinal data on the role of adversity in HPA-axis functioning. Evidence is provided that adversity can affect the body's neuroendocrine response to stress, dependent on the nature of both the HPA-measures and adverse events under study.

Human mating strategies: from past causes to present consequences

In both humans and nonhuman animals, mating strategies represent a set of evolutionary adaptations aimed at promoting individual fitness by means of reproduction with the best possible partners. Given this critical role, mating strategies influence numerous aspects of human life. In particular, between-sex divergence in the intensity of intrasexual competition could account for robust cross-cultural sex differences in psychology and behavior (e.g., personality, psychiatric disorders, social behavior, violence). Several other factors (including individual differences, relationship type and environment) affect-in an evolutionarily consistent manner-variation in mating strategy that individuals pursue (as one example, awareness of one's own attractiveness impinges on mating standards). Here we provide an overview of relevant theoretical frameworks and empirical evidence on variation in mating strategies. Given its multifaceted nature and intense research interest over several decades, this is a challenging task, and we highlight areas where further investigation is warranted in order to achieve a clearer picture and resolve apparent inconsistencies. However, we suggest that addressing outstanding questions using a variety of different methodological approaches, a deeper understanding of the cognitive representations involved in mating strategies is within reach. WIREs Cogn Sci 2018, 9:e1456. doi: 10.1002/wcs.1456 This article is categorized under: Cognitive Biology > Evolutionary Roots of Cognition Neuroscience > Behavior Neuroscience > Cognition.

Imprinting and flexibility in human face cognition

Faces are an important cue to multiple physiological and psychological traits. Human preferences for exaggerated sex typicality (masculinity or femininity) in faces depend on multiple factors and show high inter-subject variability. To gain a deeper understanding of the mechanisms underlying facial femininity preferences in men, we tested the interactive effect of family structure (birth order, sibling sex-ratio and number of siblings) and parenthood status on these preferences. Based on a group of 1304 heterosexual men, we have found that preference for feminine faces was not only influenced by sibling age and sex, but also that fatherhood modulated this preference. Men with sisters had a weaker preference for femininity than men with brothers, highlighting a possible effect of a negative imprinting-like mechanism. What is more, fatherhood increased strongly the preference for facial femininity. Finally, for fathers with younger sisters only, the more the age difference increased between them, the more femininity preference increased. Overall our findings bring new insight into how early-acquired experience at the individual level may determine face preference in adulthood, and what is more, how these preferences are flexible and potentially dependent on parenthood status in adult men.

Self-affirming trait kindness regulates disgust toward one's physical appearance

In two studies, self-affirming the behavioral trait of kindness was examined as a method of regulating state disgust toward one's physical appearance. In Study 1, 56 participants (37 women, 19 men, Mage=33.16 years) completed either a questionnaire designed to self-affirm kindness or a control equivalent and rated their disgust, anger, sadness, and happiness toward their appearance and behavior. In Study 2, 116 individuals (83 women, 33 men, Mage=24.90 years) participated in the same experiment over the internet in an ecologically valid context. When controlling for trait self-disgust, the self-affirmed in Study 1 reported significantly less disgust toward their appearance (ηp(2)=.12, p=.011). This effect was replicated in Study 2, but driven by lower state disgust levels in those higher in trait self-disgust (f(2)=.10, p=.001). Affirming valued traits, like kindness, may be a useful tool for regulating disgust toward body image.

Men's, but not women's, sociosexual orientation predicts couples' perceptions of sexually dimorphic cues in own-sex faces

Previous research suggests that people's perceptions of own-sex individuals can change according to within-individual variation in their romantic partners' sexual strategies. For example, men are more likely to perceive other men's faces as looking particularly dominant during the fertile phase of their partner's menstrual cycle, when women tend to be more open to uncommitted sexual relationships. By contrast, little is known about how relatively stable between-individuals differences in partners' openness to uncommitted sexual relationships (i.e., their sociosexual orientation) predict perceptions of own-sex individuals. The revised Sociosexual Orientation Inventory (SOI-R) assesses individuals' openness to uncommitted sexual relationships and shows high test-retest reliability over long periods of time. Consequently, we tested whether the SOI-R scores of men and women in heterosexual romantic couples predicted their perceptions of own-sex faces displaying exaggerated sex-typical cues. Men's, but not women's, SOI-R was positively correlated with the extent to which both the man and woman within a couple ascribed high dominance and attractiveness to own-sex faces with exaggerated sex-typical cues. In other words, individuals in couples where the man reported being particularly open to uncommitted sexual relationships were more likely to ascribe dominance and attractiveness to own-sex individuals displaying a putative cue of good phenotypic condition. These findings suggest that both men's and women's perceptions of potential competitors for mates are sensitive to the male partner's sexual strategy. Such individual differences in perceptions may benefit men's ability to compete for extra-pair and/or replacement mates and benefit women's mate guarding behaviors.

Early follicular testosterone level predicts preference for masculinity in male faces - but not for women taking hormonal contraception

It has been shown that women's preference for masculinity in male faces changes across the menstrual cycle. Preference for masculinity is stronger when conception probability is high than when it is low. These findings have been linked to cyclic fluctuations of hormone levels. The purpose of the present study is to further investigate the link between gonadal steroids (i.e. testosterone, estradiol, and progesterone) and masculinity preference in women, while holding the cycle phase constant. Sixty-two female participants were tested in their early follicular cycle phase, when conception probability is low. Participants were shown face pairs and where asked to choose the more attractive face. Face pairs consisted of a masculinized and feminized version of the same face. For naturally cycling women we found a positive relationship between saliva testosterone levels and masculinity preference, but there was no link between any hormones and masculinity preference for women taking hormonal contraception. We conclude that in naturally cycling women early follicular testosterone levels are associated with masculinity preference. However, these hormonal links were not found for women with artificially modified hormonal levels, that is, for women taking hormonal contraception.

Men's preferences for women's femininity in dynamic cross-modal stimuli

Men generally prefer feminine women's faces and voices over masculine women's faces and voices, and these cross-modal preferences are positively correlated. Men's preferences for female facial and vocal femininity have typically been investigated independently by presenting soundless still images separately from audio-only vocal recordings. For the first time ever, we presented men with short video clips in which dynamic faces and voices were simultaneously manipulated in femininity/masculinity. Men preferred feminine men's faces over masculine men's faces, and preferred masculine men's voices over feminine men's voices. We found that men preferred feminine women's faces and voices over masculine women's faces and voices. Men's attractiveness ratings of both feminine and masculine faces were increased by the addition of vocal femininity. Also, men's attractiveness ratings of feminine and masculine voices were increased by the addition of facial femininity present in the video. Men's preferences for vocal and facial femininity were significantly and positively correlated when stimuli were female, but not when they were male. Our findings complement other evidence for cross-modal femininity preferences among male raters, and show that preferences observed in studies using still images and/or independently presented vocal stimuli are also observed when dynamic faces and voices are displayed simultaneously in video format.