How Willing Are You to Accept Sexual Requests from Slightly Unattractive to Exceptionally Attractive Imagined Requestors?

In their classic study of differences in mating strategies, Clark and Hatfield (1989, Journal of Psychology and Human Sexuality, 2, 39–54) found that men and women demonstrated a striking difference in interest in casual sex. The current study examined the role of an imagined requestor’s physical attractiveness (slightly unattractive, moderately attractive, and exceptionally attractive) on men’s and women’s willingness to accept three different requests (go out, come to apartment, go to bed) as reflected in answers to a questionnaire. We tested two hypotheses with a sample of 427 men and 443 women from three countries. Hypothesis 1 states that men, relative to women, will demonstrate a greater willingness to accept the “come to apartment” and “go to bed” requests but not the “go out” request for all three levels of requestor attractiveness. This hypothesis reflects Clark and Hatfield’s main findings. Hypothesis 2 states that the physical attractiveness of a potential partner will have a greater effect on women’s than on men’s willingness to accept all three requests, and particularly for the explicit request for casual sex. The results partially supported Hypothesis 1 and fully supported Hypothesis 2. The discussion highlights limitations of the current research and presents directions for future research.     

Partner Status Influences Women’s Interest in the Opposite Sex

Previous research has demonstrated that hormones, relationship goals, and social context influence interest in the opposite sex. It has not been previously reported, however, whether having a current sexual partner also influences interest in members of the opposite sex. To test this, we obtained explicit and implicit measures of interest by measuring men’s and women’s subjective ratings and response times while they evaluated photos of opposite-sex faces. Fifty-nine men and 56 women rated 510 photos of opposite-sex faces for realism, masculinity, attractiveness, or affect. We found that these subjective ratings were not influenced by partner status in either men or women. However, women who did not report having a current sexual partner spent more time evaluating the photos than women who did have partners, demonstrating greater interest in the photos. Sexual partner status did not predict men’s response times. These findings may reveal that relationship commitment in women suppresses interest in alternative partners.

Who Cares About Marrying a Rich Man? Intelligence and Variation in Women’s Mate Preferences

Although robust sex differences are abundant in men and women’s mating psychology, there is a considerable degree of overlap between the two as well. In an effort to understand where and when this overlap exists, the current study provides an exploration of within-sex variation in women’s mate preferences. We hypothesized that women’s intelligence, given an environment where women can use that intelligence to attain educational and career opportunities, would be: (1) positively related to their willingness to engage in short-term sexual relationships, (2) negatively related to their desire for qualities in a partner that indicated wealth and status, and (3) negatively related to their endorsement of traditional gender roles in romantic relationships. These predictions were supported. Results suggest that intelligence may be one important individual difference influencing women’s mate preferences.     

Relative digit lengths predict men’s behavior and attractiveness during social interactions with women

Recent evidence suggests that the ratio of the lengths of the second and fourth fingers (2D:4D) may reflect degree of prenatal androgen exposure in humans. In the present study, we tested the hypotheses that 2D:4D would be associated with ratings of men’s attractiveness and with levels of behavioral displays during social interactions with potential mates. Our results confirm that male 2D:4D was significantly negatively correlated with women’s ratings of men’s physical attractiveness and levels of courtship-like behavior during a brief conversation. These findings provide novel evidence for the organizational effects of hormones on human male attractiveness and social behavior. This work was supported by a Hind’s Fund Research Grant from the Committee on Evolutionary Biology at the University of Chicago to J.R.R. and by NIH grants R01-MH62577 and K02-MH63097 to D.M. James Roney, Ph.D., is now an assistant professor of psychology at the University of California, Santa Barbara. His research interests are in human evolutionary psychology and behavioral endocrinology. Dario Maestripieri, Ph.D., is an associate professor of Human Development at the University of Chicago. He has broad research interests in behavior, development, and evolution.     

Physical attractiveness influences reproductive success of modern men

Theory suggests that reproductive success is positively associated with an individual’s genetic quality. However, the association between physical attractiveness and reproductive success (i.e., number of offspring) in modern humans remains less clear. Here we examined associations between men’s reproductive success and physical attractiveness from retrospective data obtained from married, divorced, and single samples of Slovakian men. As predicted, facially more attractive and taller men were more likely to engage in marriage. In turn, married men had higher reproductive success than single men. Even when men’s marital status was considered, facially more attractive men had higher reproductive success than their less attractive counterparts. This supports the importance of physical attractiveness in sexual selection in modern humans.     

Willingness to Act upon Beliefs about ‘Treatment as Prevention’ among Australian Gay and Bisexual Men

HIV ‘treatment as prevention’ (TasP) is highly effective in reducing HIV transmission in serodiscordant couples. There has been little examination of gay and bisexual men’s attitudes towards TasP, particularly regarding men’s willingness to act on beliefs about TasP. We conducted an online cross-sectional survey of Australian men in late 2012 to investigate knowledge and beliefs about new developments in HIV prevention. Amongst 839 men (mean age 39.5 years), men tended to disagree that TasP was sufficiently effective to justify reduced condom use, although HIV-positive men had more favourable attitudes. Only a minority of men were aware of any evidence for TasP; and one-quarter incorrectly believed that evidence for the effectiveness of TasP already existed for the homosexual population. One-fifth (20.5%) of men reported that they would be willing to have condomless anal intercourse with an opposite-status sexual partner when the HIV-positive partner was taking HIV treatments. Factors independently associated with such willingness were: HIV-positive serostatus, reporting any serodiscordant or serononconcordant condomless anal intercourse with a regular male partner in the previous six months, reporting any condomless anal intercourse with a casual male partner in the previous six months, and having greater beliefs in the effectiveness of TasP. This indicated that the men most willing to rely on TasP to prevent transmission were already engaging in higher risk practices. Biomedical HIV prevention represents a rapidly changing environment with new research as well as community and policy responses emerging at a fast pace. For men with serodiscordant sexual partners to successfully apply TasP to reducing transmission risk, more support and education is needed to enable better utilisation of TasP in specific relational and sexual contexts.     

Sexual selection and physical attractiveness

Sexual selection processes have received much attention in recent years, attention reflected in interest in human mate preferences. Among these mate preferences are preferences for physical attractiveness. Preferences in and of themselves, however, do not fully explain the nature of the relationships that individuals attain. A tacit negotiation process underlies relationship formation and maintenance. The notion that preferences for physical attractiveness evolved under parasite-driven “good genes” sexual selection leads to predictions about the nature of trade-offs that individuals make between mates’ physical attractiveness and investment potential. These predictions and relevant data are explored, with a primary emphasis on women’s preferences for men’s qualities. In addition, further implications of trade-offs are examined, most notably (a) the impact of environmental variations on the nature of mating and (b) some effects of trade-offs on infidelity and male attempts to control women. The ideas in this paper were substantially influenced by discussions with Kim Hill and Hilly Kaplan following a preliminary presentation of work contained herein at a UNM Human Evolutionary Ecology Program colloquium. Steven W. Gangestad is an associate professor of psychology at the University of New Mexico. His recent research includes work focused on sexual selection in humans and its implications for general relationship phenomena. His other recent research concerns the impact of developmental instability on functional asymmetries, interpersonal orientations, and individual differences in the control of emotional expression.     

High accumulations of calcium and phosphorus in women’s pubic symphysis

To elucidate compositional changes of the pubic symphysis (PS) by aging, elements of pubic symphyses (PSs) removed from 26 cadavers were determined by inductively coupled plasma atomic-emission spectrometry. It was found that the relative contents (RCs) of calcium and phosphorus in women’s PSs were about three-and five-fold amounts as compared with those in men’s PSs, respectively. In contrast, the RCs of sulfur, magnesium, sodium, and iron in women’s PSs were somewhat lower than those in men’s PSs. The accumulations of calcium (Ca) and phosphorus (P) in women’s PSs occurred mainly beyond the age of 70-yr-old, but did not occur in men’s PSs.     

Mate choice trade-offs and women’s preference for physically attractive men

Researchers studying human sexuality have repeatedly concluded that men place more emphasis on the physical attractiveness of potential mates than women do, particularly in long-term sexual relationships. Evolutionary theorists have suggested that this is the case because male mate value (the total value of the characteristics that an individual possesses in terms of the potential contribution to his or her mate’s reproductive success) is better predicted by social status and economic resources, whereas women’s mate value hinges on signals conveyed by their physical appearance. This pattern may imply that women trade off attractiveness for resources in mate choice. Here I test whether a trade-off between resources and attractiveness seems to be occurring in the mate choice decisions of women in the United States. In addition, the possibility that the risk of mate desertion drives women to choose less attractive men as long-term mates is tested. The results were that women rated physically attractive men as more likely to cheat or desert a long-term relationship, whereas men did not consider attractive women to be more likely to cheat. However, women showed no aversion to the idea of forming long-term relationships with attractive men. Evidence for a trade-off between resources and attractiveness was found for women, who traded off attractiveness, but not other traits, for resources. The potential meaning of these findings, as well as how they relate to broader issues in the study of sex differences in the evolution of human mate choice for physical traits, is discussed.     

Age-related changes of bone mineral density in human calcaneus, talus, and scaphoid bone

To examine whether the bone mineral density (BMD) decreases uniformly with aging in any spongy bones, the authors investigated age-related changes of BMD in the calcaneus, talus, and scaphoid bone. After the ordinary dissection by medical students was finished, calcanei, tali, and scaphoid bones were resected from the subjects, and BMDs were measured by dual-energy X-ray absorptiometry. Their BMDs seemed to decrease gradually with aging in the calcanei, tali, and scaphoid bones. It was found that there were statistically significant relationships between age and BMD in the men’s and women’s scaphoid bones, women’s tali, and women’s calcanei, but not in the men’s tali and calcanei. It should be noted that there were significant relationships between age and BMD in both men’s and women’s scaphoid bones. In regard to relationship in BMD between the bones of the upper and lower limbs in individuals, it was found that the relationship between the calcaneus and talus was higher than that between the calcaneus and scaphoid bone. This suggests that there is a higher relationship in BMD between the two tarsal bones compared with that between the tarsal and carpal bones.     

Kinship,Family, and Gender Effects in the Ultimatum Game

Kinship and reciprocity are two main predictors of altruism. The ultimatum game has been used to study altruism in many small-scale societies. We used the ultimatum game to examine effects of individuals’ family and kin relations on altruistic behavior in a kin-based horticultural community in rural Dominica. Results show sex-specific effects of kin on ultimatum game play. Average coefficient of relatedness to the village was negatively associated with women’s ultimatum game proposals and had little effect on men’s proposals. Number of brothers in the village was positively associated with men’s ultimatum game proposals and negatively associated with women’s proposals. Similarly, presence of father in the village was associated with higher proposals by men and lower proposals by women. We interpret the effect of brothers on men’s proposals as a consequence of local competition among brothers. We speculate that daughter-biased parental care in this community creates a sense of entitlement among women with brothers, which may explain the inverse relation between number of brothers and women’s ultimatum game proposals. The pattern of results may be consistent with how matrifocality affects cultural models of fairness differently along gender and family lines.     

Mate Choice Copying in Humans

There is substantial evidence that in human mate choice, females directly select males based on male display of both physical and behavioral traits. In non-humans, there is additionally a growing literature on indirect mate choice, such as choice through observing and subsequently copying the mating preferences of conspecifics (mate choice copying). Given that humans are a social species with a high degree of sharing information, long-term pair bonds, and high parental care, it is likely that human females could avoid substantial costs associated with directly searching for information about potential males by mate choice copying. The present study was a test of whether women perceived men to be more attractive when men were presented with a female date or consort than when they were presented alone, and whether the physical attractiveness of the female consort affected women’s copying decisions. The results suggested that women’s mate choice decision rule is to copy only if a man’s female consort is physically attractive. Further analyses implied that copying may be a conditional female mating tactic aimed at solving the problem of informational constraints on assessing male suitability for long-term sexual relationships, and that lack of mate choice experience, measured as reported lifetime number of sex partners, is also an important determinant of copying.     

Judging the Difference between Attractiveness and Health: Does Exposure to Model Images Influence the Judgments Made by Men and Women?

Recent research has shown facial adiposity (apparent weight in the face) to be a significant predictor of both attractiveness and health, thus making it an important determinant of mate selection. Studies looking at the relationship between attractiveness and health have shown that individuals differentiate between the two by preferring a lower weight for attractiveness than for health in female faces. However, these studies have either been correlational studies, or have investigated weight perceived from only the face. These differences have been discussed with regard to sociocultural factors such as pressure from parents, peers and also media, which has been seen to have the highest influence. While exposure to media images has been shown to influence women’s own-body image, no study has yet directly tested the influence of these factors on people’s preferred weight in other women’s bodies. Here we examine how a short exposure to images of models influences men’s and women’s judgments of the most healthy looking and attractive BMI in Malaysian Chinese women’s bodies by comparing differences in preferences (for attractiveness and health) between groups exposed to images of models of varying attractiveness and body weight. Results indicated that participants preferred a lower weight for attractiveness than for health. Further, women’s but not men’s preferred BMI for attractiveness, but not health, was influenced by the type of media images to which they were exposed, suggesting that short term exposure to model images affect women’s perceptions of attractiveness but not health.     

Fertility in the cycle predicts women's interest in sexual opportunism

Research over the past decade has documented clear, robust changes in women's sexual preferences and interests across the ovarian cycle. When fertile, women are particularly attracted to a number of masculine male features (e.g., masculine faces, voices, scents and bodies) and other traits, and especially when they evaluate men's “sexiness” rather than their attractiveness as long-term partners. The current research extended this line of research by examining changes in women's self-reported sexual interests across the cycle. We asked 68 normally ovulating women in committed romantic relationships to fill out questionnaires about their sexual preferences and interests (at that time, not in general) twice across their cycles: once when fertile and once during the luteal phase. Relative to during the luteal phase, fertile women expressed (a) greater emphasis on the physical attractiveness of a partner; (b) greater arousal at the sight or thought of attractive male bodily features; (c) greater willingness to engage in and interest in sex with attractive men, even ones who they do not know well (interest in sexual opportunism). These findings importantly extend our understanding of women's fertile-phase sexuality.     

Watching the Hourglass

Eye-tracking techniques were used to measure men’s attention to back-posed and front-posed images of women varying in waist-to-hip ratio (WHR). Irrespective of body pose, men rated images with a 0.7 WHR as most attractive. For back-posed images, initial visual fixations (occurring within 200 milliseconds of commencement of the eye-tracking session) most frequently involved the midriff. Numbers of fixations and dwell times throughout each of the five-second viewing sessions were greatest for the midriff and buttocks. By contrast, visual attention to front-posed images (first fixations, numbers of fixations, and dwell times) mainly involved the breasts, with attention shifting more to the midriff of images with a higher WHR. This report is the first to compare men’s eye-tracking responses to back-posed and front-posed images of the female body. Results show the importance of the female midriff and of WHR upon men’s attractiveness judgments, especially when viewing back-posed images.     

Human mate choice and the wedding ring effect

Individuals are often restricted to indirect cues when assessing the mate value of a potential partner. Females of some species have been shown to copy each other’s choice; in other words, the probability of a female choosing a particular male increases if he has already been chosen by other females. Recently it has been suggested that mate-choice copying could be an important aspect of human mate choice as well. We tested one of the hypotheses, the so-called wedding ring effect—that women would prefer men who are already engaged or married—in a series of live interactions between men and women. The results show that women do not find men signaling engagement, or being perceived as having a partner, more attractive or higher in socioeconomic status. Furthermore, signs of engagement did not influence the women’s reported willingness to engage in short-term or long-term relationships with the men. Thus, this study casts doubt on some simplified theories of human mate-choice copying, and alternative, more complex scenarios are outlined and discussed. Tobias Uller works on broad issues in evolutionary biology, such as life-history evolution and evolutionary genetics. Christoffer Johansson recently received his Ph.D. with a dissertation on biomechanics of swimming birds. Their collaborative work on humans is focused on mate choice.     

Sex differences in political leadership in an egalitarian society

We test the contribution of sex differences in physical formidability, education, and cooperation to the acquisition of political leadership in a small-scale society. Among forager-farmers from the Bolivian Amazon, we find that men are more likely to exercise different forms of political leadership, including verbal influence during community meetings, coordination of community projects, and dispute resolution. We show that these differences in leadership are not due to gender per se but are associated with men's greater number of cooperation partners, greater access to schooling, and greater body size and physical strength. Men's advantage in cooperation partner number is tied to their participation in larger groups and to the opportunity costs of women's intrahousehold labor. We argue these results highlight the mutual influence of sexual selection and the sexual division of labor in shaping how women and men acquire leadership.     

Estrogenic and progestogenic effects of hormonal contraceptives in relation to sexual behavior: insights into extended sexuality

Women's mating adaptations may vary between fertile and luteal phases, given different costs and benefits of sexual activity during each phase. Women's non-conceptive (“extended”) sexuality might function in the context of pair-bonding. The current studies examined associations between women's loyalty and faithfulness to their relationships and frequency of sexual intercourse in women using hormonal contraception. As predicted, in study 1 estimated levels (adjusted for potency) of both synthetic estrogen and progestin delivered to women moderated the association between women's loyalty/faithfulness to their partner and frequency of intercourse: as estradiol levels diminished, and progestin levels increased, women's loyalty/faithfulness became more positively associated with frequency of intercourse. Study 2 replicated these findings in a sample of women studied over a 12 week period. Results further support claims for a possible function of extended sexuality, and speak to hormonal mechanisms affecting it. They also have important methodological and applied implications.     

Age-related changes of element contents in the human meniscus

The relative contents (RCs) of elements in the human menisci from 23 subjects in the age range between 65 and 93 yr were analyzed by inductively coupled plasma atomic emission spectrometry. The RCs of sulfur, calcium, and phosphorus in menisci increased progressively until the 80s, being the highest in the 80s, and thereafter decreased. The RCs of magnesium in menisci increased progressively until the 90s. Regarding the medial and lateral menisci, higher RCs of magnesium and iron, and a lower RC of phosphorus were found in lateral menisci in comparison with those in medial menisci. There were sexual differences in the RCs of calcium and phosphorus of medial and lateral menisci. The RCs of calcium and phosphorus were about 50% higher in women’s menisci than in men’s. Histological examinations showed that structureless mucoid masses were observed in the menisci, with very high RCs of calcium and phosphorus being detected.