Women's estradiol predicts preference for facial cues of men's testosterone

Hormonal Underpinnings of the Variation in Sexual Desire, Arousal and Activity Throughout the Menstrual Cycle - A Multifaceted Approach

Although prior evidence supports women's mating behaviors and preferences being related to ovarian hormonal levels, there is conflicting evidence about exactly which hormones predict sexual function best, which specific psychosexual facets are affected and how between-individual and within-individual differences relate to this question. In this study levels of estradiol and progesterone were measured (once daily for 15 days for each participant) for 97 women, who attended two testing sessions, in times of the cycle varying in conception probability (based on the luteinizing hormone (LH) test result). Women completed surveys on their sexual desire, arousal, sexual activity frequency and initiation. There was a significant difference between peri-ovulatory and luteal values for all sexual function variables. Between-subject progesterone negatively predicted sexual activity frequency only. Within-subject estradiol positively and progesterone negatively predicted sexual desire. The findings provide support for hormonal underpinnings of sexual desire and sexual activity frequency fluctuations during the menstrual cycle. The findings did not yield support for hormonal influences on sexual arousal and initiation of sexual encounters. The main findings are consistent with the excitatory and inhibitory effects of estradiol and progesterone, respectively, on measures of women's sexual motivation.

The role of hormones in attraction and visual attention to facial masculinity

The current study investigated the ovulatory shift hypothesis, which suggests that women prefer more masculine traits when estradiol is high, and progesterone is low (E/P ratio). The current study used an eye tracking paradigm to measure women's visual attention to facial masculinity across the menstrual cycle. Estradiol (E) and progesterone (P) were collected to determine if salivary biomarkers were associated with visual attention to masculine faces in a short- and long-term mating context. Women (N = 81) provided saliva samples at three time points throughout their menstrual cycle and were asked to rate and view men's faces that had been manipulated to appear feminine and masculine. Overall, masculine faces were viewed longer compared to feminine faces and this was moderated by mating context, where women viewed masculine faces longer for a long-term relationship. There was not any evidence suggesting that E/P ratio was associated with preferences for facial masculinity, but there was evidence to suggest that hormones were associated with visual attention to men in general. In line with sexual strategies theory, there was evidence to suggest that mating context and facial masculinity are important in mate choice; however, there was no evidence to suggest that women's mate choice was associated with shifts across the menstrual cycle.

Functional brain network topology across the menstrual cycle is estradiol dependent and correlates with individual well-being

The menstrual cycle (MC) is a sex hormone‐related phenomenon that repeats itself cyclically during the woman's reproductive life. In this explorative study, we hypothesized that coordinated variations of multiple sex hormones may affect the large‐scale organization of the brain functional network and that, in turn, such changes might have psychological correlates, even in the absence of overt clinical signs of anxiety and/or depression. To test our hypothesis, we investigated longitudinally, across the MC, the relationship between the sex hormones and both brain network and psychological changes. We enrolled 24 naturally cycling women and, at the early‐follicular, peri‐ovulatory, and mid‐luteal phases of the MC, we performed: (a) sex hormone dosage, (b) magnetoencephalography recording to study the brain network topology, and (c) psychological questionnaires to quantify anxiety, depression, self‐esteem, and well‐being. We showed that during the peri‐ovulatory phase, in the alpha band, the leaf fraction and the tree hierarchy of the brain network were reduced, while the betweenness centrality (BC) of the right posterior cingulate gyrus (rPCG) was increased. Furthermore, the increase in BC was predicted by estradiol levels. Moreover, during the luteal phase, the variation of estradiol correlated positively with the variations of both the topological change and environmental mastery dimension of the well‐being test, which, in turn, was related to the increase in the BC of rPCG. Our results highlight the effects of sex hormones on the large‐scale brain network organization as well as on their possible relationship with the psychological state across the MC. Moreover, the fact that physiological changes in the brain topology occur throughout the MC has widespread implications for neuroimaging studies.

An agent-based model of the female rivalry hypothesis for concealed ovulation in humans

After half a century of debate and few empirical tests, there remains no consensus concerning why ovulation in human females is considered concealed. The predominant male investment hypothesis states that females were better able to obtain material investment from male partners across those females' ovulatory cycles by concealing ovulation. We build on recent work on female competition to propose and investigate an alternative-the female rivalry hypothesis-that concealed ovulation benefited females by allowing them to avoid aggression from other females. Using an agent-based model of mating behaviour and paternal investment in a human ancestral environment, we did not find strong support for the male investment hypothesis, but found support for the female rivalry hypothesis. Our results suggest that concealed ovulation may have benefitted females in navigating their intrasexual social relationships. More generally, this work implies that explicitly considering female-female interactions may inspire additional insights into female behaviour and physiology.

Non-Pregnant and Pregnant Women's Femininity Preferences in Male Faces: Tests Based on Within- and Between-Sex Sexual Dimorphism Facial Manipulations

Past research on women's preferences for male facial masculinity in Western cultures has produced inconsistent results. Some inconsistency may be related to the use of different facial stimulus manipulations (e.g., between-sex sexual dimorphic facial manipulation or within-sex sexual dimorphic facial manipulation) that do not perfectly avoid non-facial cues, and pregnancy status may also influence women's face preferences. We therefore recruited pregnant and nonpregnant Chinese women and manipulated the sexual dimorphism of male facial stimuli to explore the influences of manipulation methods, non-facial cues, and pregnancy status on face preferences. Results showed that: (1) in contrast with a general masculinity preference observed in Western cultures, both pregnant and nonpregnant Chinese women preferred feminized and neutral male faces generally; (2) pregnant women's preference for feminized male faces was stable across manipulation methods, while nonpregnant women preferred feminized male faces except under between-sex sexual dimorphism manipulation; and (3) manipulation methods, rather than non-facial cues, influenced participants' face preferences. Specifically, women showed the strongest preferences for femininity when face stimuli were manipulated by within-sex sexual dimorphic facial manipulation, followed by unmanipulated faces and between-sex sexual dimorphic facial manipulation. This effect was stronger for nonpregnant women in the unmanipulated condition and for pregnant women in the between-sex sexual dimorphic facial manipulation. This research provides empirical evidence of women's preferences for sexual dimorphism in male faces in a non-Western culture, as well as the effects of facial manipulation methods, pregnancy status, and the interactions between these factors.

Mapping changes in women's visual functions during the menstrual cycle: narrative review

BACKGROUND

This article systematically updates the literature on changes in visual functions during the phases of the normal menstrual cycle in women.

OBJECTIVES

To update Guttridge's 1994 review of visual structures and functions associated with the menstrual cycle and broaden the search through psychophysical, neuroimaging and neurobehavioral measurements covering 1994-2020.

DESIGN AND SETTING

Narrative review conducted in a neurosciences and behavior laboratory in Brazil.

METHODS

The PubMed, Cochrane Clinical Answers and Google Scholar databases were searched. After screening and applying the eligibility criteria, 32 articles were examined. Through this analysis, the following information was extracted: (1) geographical distribution of the study; (2) sample size (according to age and phase of the menstrual cycle); (3) type of measurements according to psychophysical, neuroimaging and neurobehavioral instruments; (4) vision testing model; (5) visual subcategory evaluated; (6) categories of processed visual stimuli; and (7) main findings.

RESULTS

The menstrual phases give rise to significant changes in visual functions, including in relation to orientation and spatial attention, visual campimetry and visual sensitivity. These relate specifically to the follicular and luteal phases.

CONCLUSIONS

These findings theoretically expand the effects of menstrual cycles on visual functions found by Guttridge (1994). Despite some inconsistencies in the studies analyzed, it was found that visual processing during the follicular and luteal phases of the normal menstrual cycle of healthy women can explain physiological, cognitive, behavioral and social modulations.

Jealousy Incarnate: Quiet Ego, Competitive Desire, and the Fictional Intelligence of Long-Term Mating in a Romantic K-Drama

In this paper, we analyze a K-drama aired by the Korean TV network SBS in 2016, Jealousy Incarnate, as a case study of the application of the Tie-Up Theory to a romantic narrative as a form of simulation of human mating processes with social cognition valence. We find that this case provides us with an example of a mating process where the choice of the male partner by the female lead character does not privilege the one that should be preferable on the basis of the standard prediction of the experimental research on human mating. This discrepancy is a signal of a basic limitation of experimental research, that highlights the subjects’ preferences for abstract potential partners but is not able to fully account for the mechanisms that lead to the choice of a specific partner in a specific mating interaction. We argue that the narrative simulation viewpoint provides insights that are complementary to those of experimental research, and that a more comprehensive theoretical approach, such as the one offered by the Tie-Up Theory, may be helpful to account for both perspectives.

Evolution, the Menstrual Cycle, and Theoretical Overreach

A considerable amount of recent psychological research has attributed a variety of menstrual-cycle-related changes in social behavior to evolutionarily adaptive functions. Although these studies often draw interesting and unusual conclusions about female emotion and behavior within evolutionary theory, their significant limitations have not yet been addressed. In this article, we outline several methodological and conceptual issues related to the menstrual cycle that constitute threats to the internal validity and theoretical integrity of these studies. We recommend specific guidelines to address these issues and emphasize the need to apply more comprehensive and sophisticated theoretical structures when considering menstrual-cycle-related changes in emotion and behavior.

Mothers are sensitive to men's beards as a potential cue of paternal investment

Mating strategy theories assert that women's preferences for androgen dependent traits in men are stronger when the costs of reduced paternal investment are lowest. Past research has shown that preferences for facial masculinity are stronger among nulliparous and non-pregnant women than pregnant or parous women. In two studies, we examine patterns in women's preferences for men's facial hair - likely the most visually conspicuous and sexually dimorphic of men's secondary sexual traits - when evaluating men's masculinity, dominance, age, fathering, and attractiveness. Two studies were conducted among heterosexual pregnant women, mothers, non-contractive and contraceptive users. Study 1 used a between-subjects sample (N = 2103) and found that mothers had significantly higher preferences for beards when judging fathering than all other women. Pregnant women and mothers also judged beards as more masculine and older, but less attractive, than non-contractive and contraceptive users. Parous women judged beards higher for age, masculinity and fathering, but lower for attractiveness, than nulliparous women. Irrespective of reproductive status, beards were judged as looking more dominant than clean-shaven faces. Study 2 used a within-subjects design (N = 53) among women surveyed during pregnancy and three months post-partum. Judgments of parenting skills were higher for bearded stimuli during pregnancy among women having their first baby, whereas among parous women parenting skills judgments for bearded stimuli were higher post-partum. Our results suggest that mothers are sensitive to beardedness as a masculine secondary sexual characteristic that may denote parental investment, providing evidence that women's mate preferences could reflect sexual selection for direct benefits.

Ovulatory Shifts in Sexual Desire But Not Mate Preferences: An LH-Test-Confirmed, Longitudinal Study

The presented data are part of a longitudinal within-subject study designed to examine ovulatory shifts in human sexuality in a diverse German sample using validated questionnaires. The final sample consists of 78 individuals (76 female, 2 agender) who declared to be mainly or exclusively attracted to males. Questionnaires were completed anonymously online at three cycle phases. Following the gold standard, the fertile window was calculated through the reverse cycle day method and confirmed via urinary tests detecting luteinizing hormone. The questionnaire included the Sexual Desire Inventory, Dresdner Body Image Inventory, the Revised Sociosexual Orientation Inventory, and an adjective list to measure mate preferences. One hundred eighty-four questionnaires were included in the data analysis using linear mixed models. Findings support previous research reporting heightened sexual desire and an improved body image during the fertile window. No shifts were found for mate preference or sociosexual orientation, thus adding to a growing body of literature contesting parts of the ovulatory shift hypothesis.

Does testosterone predict women's preference for facial masculinity?

The influence of sex hormones on women’s mate preferences has been an intensively discussed topic for more than a decade. Yet the extent to which levels of sex hormones, and testosterone in particular, influence women’s mate preferences is unclear. Thus, the current study used multilevel modelling to investigate putative relationships between salivary testosterone and facial masculinity preferences in a sample of 68 women, while controlling for their age, partnership status, and sociosexuality. We found no significant associations between masculinity preferences and either individual differences or within-woman changes in testosterone. We did find however, that sociosexuality was positively correlated with masculinity preferences. Although it has previously been suggested that testosterone is related to women’s facial masculinity preference, our data do not support this proposal.

Oral Contraceptives Impair Complex Emotion Recognition in Healthy Women

Despite the widespread use of oral contraceptives (OCs), remarkably little is known about the effects of OCs on emotion, cognition, and behavior. However, coincidental findings suggest that OCs impair the ability to recognize others’ emotional expressions, which may have serious consequences in interpersonal contexts. To further investigate the effects of OCs on emotion recognition, we tested whether women who were using OCs (n = 42) would be less accurate in the recognition of complex emotional expressions than women who were not using OCs (n = 53). In addition, we explored whether these differences in emotion recognition would depend on women’s menstrual cycle phase. We found that women with OC use were indeed less accurate in the recognition of complex expressions than women without OC use, in particular during the processing of expressions that were difficult to recognize. These differences in emotion recognition did not depend on women’s menstrual cycle phase. Our findings, thus, suggest that OCs impair women’s emotion recognition, which should be taken into account when informing women about the side-effects of OC use.

Ovulation, Sex Hormones, and Women's Mating Psychology

The dual mating strategy hypothesis proposes that women's preferences for uncommitted sexual relationships with men displaying putative fitness cues increase during the high-fertility phase of the menstrual cycle. Results consistent with this hypothesis are widely cited as evidence that sexual selection has shaped human mating psychology. However, the methods used in most of these studies have recently been extensively criticized. Here we discuss (i) new empirical studies that address these methodological problems and largely report null results and (ii) an alternative model of hormonal regulation of women's mating psychology that can better accommodate these new data.

The role of mating context and fecundability in women's preferences for men's facial masculinity and beardedness

The ovulatory shift hypothesis proposes that women's preferences for masculine physical and behavioral traits are greater at the peri-ovulatory period than at other points of the menstrual cycle. However, many previous studies used self-reported menstrual cycle data to estimate fecundability rather than confirming the peri-ovulatory phase hormonally. Here we report two studies and three analyses revisiting the ovulatory shift hypothesis with respect to both facial masculinity and beardedness. In Study 1, a large sample of female participants (N = 2,161) self-reported their cycle phase and provided ratings for faces varying in beardedness (clean-shaven, light stubble, heavy stubble, full beards) and masculinity (-50%, -25%, natural, +25% and +50%) in a between-subjects design. In Study 2, 68 women provided the same ratings data, in a within-subjects design in which fertility was confirmed via luteinising hormone (LH) tests and analysed categorically. In Study 2, we also measured salivary estradiol (E) and progesterone (P) at the low and high fertility phases of the menstrual cycle among 36 of these women and tested whether shifts in E, P or E:P ratios predicted face preferences. Preferences for facial masculinity and beardedness did not vary as predicted with fecundability in Study 1, or with respect to fertility as confirmed via LH in Study 2. However, consistent with the ovulatory shift hypothesis, increasing E (associated with cyclical increases in fecundability) predicted increases in preferences for relatively more masculine faces; while high P (associated with cyclical decreases in fecundability) predicted increases in preferences for relatively more feminine faces. We also found an interaction between E and preferences for facial masculinity and beardedness, such that stubble was more attractive on un-manipulated than more masculine faces among women with high E. We consider discrepancies between our findings and those of other recent studies and suggest that closer scrutiny of the stimuli used to measure masculinity preferences across studies may help account for the many conflicting findings that have recently appeared regarding cycle phase preference shifts for facial masculinity.

Intrinsic links among sex, emotion, and reproduction

Species survival is dependent on successful reproduction. This begins with a desire to mate, followed by selection of a partner, copulation and in monogamous mammals including humans, requires emotions and behaviours necessary to maintain partner bonds for the benefit of rearing young. Hormones are integral to all of these stages and not only mediate physiological and endocrine processes involved in reproduction, but also act as neuromodulators within limbic brain centres to facilitate the expression of innate emotions and behaviours required for reproduction. A significant body of work is unravelling the roles of several key hormones in the modulation of mood states and sexual behaviours; however, a full understanding of the integration of these intrinsic links among sexual and emotional brain circuits still eludes us. This review summarises the evidence to date and postulates future directions to identify potential psycho-neuroendocrine frameworks linking sexual and emotional brain processes with reproduction.

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.

Human colour in mate choice and competition

The colour of our skin and clothing affects how others perceive us and how we behave. Human skin colour varies conspicuously with genetic ancestry, but even subtle changes in skin colour due to diet, blood oxygenation and hormone levels influence social perceptions. In this review, we describe the theoretical and empirical frameworks in which human colour is researched. We explore how subtle skin colour differences relate to judgements of health and attractiveness. Also, because humans are one of the few organisms able to manipulate their apparent colour, we review how cosmetics and clothing are implicated in courtship and competition, both inside the laboratory and in the real world. Research on human colour is in its infancy compared with human psychophysics and colour research in non-human animals, and hence we present best-practice guidelines for methods and reporting, which we hope will improve the validity and reproducibility of studies on human coloration.This article is part of the themed issue 'Animal coloration: production, perception, function and application'.

La donna è mobile? Lack of cyclical shifts in facial symmetry, and facial and body masculinity preferences-A hormone based study

Although under investigation for more than two decades, a common agreement on the occurrence of cyclical shifts in women's masculinity and symmetry preferences is still missing. Such shifts are considered to be an important feature of sexual selection as they supposedly direct women's attention towards cues for "good genes" (e.g. masculinity and symmetry) during times when probability of conception is the highest. Multiple studies have, however, failed to find these shifts. We attempt to address this lack of agreement analysing a sample of 110 healthy women, using intra-participant design and repeated measurements of oestradiol and LH during the cycle. To ensure the reliable detection of increased conception probability, both LH- based ovulation tests and multiple oestradiol measurements were used. We found no significant differences between women's preferences during different cycle phases for either body or facial masculinity, or for facial symmetry. Differences remained non-significant after controlling for participants' sexual openness, relationship status, and self-judged attractiveness. We suggest that putative cyclical shifts in preferences for cues for good genes are either very small (impossible to be tracked even with a relatively large sample) or they are far more complex than previously assumed, and further studies accounting for more confounding variables should be undertaken.

Natural variation in female reproductive hormones does not affect contrast sensitivity

Evidence suggests that females experience adaptive shifts in facial preferences across the menstrual cycle. However, recent discussions and meta-analyses suggest that these findings are equivocal. A previously unexplored question is the extent to which shifts in female preferences are modulated by hormone-dependent changes occurring in low-level vision, such as visual sensitivity. This mechanistic approach has been a novel method for investigating the extent to which complex perceptual phenomena are driven by low-level versus higher-level perceptual processes. We investigated whether the contrast sensitivity function-an early dimension of vision-is also influenced by variation in female reproductive hormones. Visual contrast thresholds were measured for 1, 4 and 16 cycles/degree gratings during the ovulatory, luteal and menstrual phases of the menstrual cycle in naturally cycling women, and women using oral contraceptives. Male participants were tested at similar time intervals. Results showed that visual contrast sensitivity does not differ according to sex, or use of oral contraception, nor does it vary relative to hormonal shifts across the menstrual cycle. These findings suggest that shifts in female preferences are not driven by changes in visual sensitivity, and are therefore likely attributable to changes in higher-level perception or cognition.

Women's preferences for men's beards show no relation to their ovarian cycle phase and sex hormone levels

According to the ovulatory shift hypothesis, women's mate preferences for male morphology indicative of competitive ability, social dominance, and/or underlying health are strongest at the peri-ovulatory phase of the menstrual cycle. However, recent meta-analyses are divided on the robustness of such effects and the validity of the often-used indirect estimates of fertility and ovulation has been called into question in methodological studies. In the current study, we test whether women's preferences for men's beardedness, a cue of male sexual maturity, androgenic development and social dominance, are stronger at the peri-ovulatory phase of the menstrual cycle compared to during the early follicular or the luteal phase. We also tested whether levels of estradiol, progesterone, and the estradiol to progesterone ratio at each phase were associated with facial hair preferences. Fifty-two heterosexual women completed a two-alternative forced choice preference test for clean-shaven and bearded male faces during the follicular, peri-ovulatory (validated by the surge in luteinizing hormone or the drop in estradiol levels) and luteal phases. Participants also provided for one entire menstrual cycle daily saliva samples for subsequent assaying of estradiol and progesterone. Results showed an overall preference for bearded over clean-shaven faces at each phase of the menstrual cycle. However, preferences for facial hair were not significantly different over the phases of menstrual cycle and were not significantly associated with levels of reproductive hormones. We conclude that women's preferences for men's beardedness may not be related to changes in their likelihood of conception.

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.

Efficacy of methods for ovulation estimation and their effect on the statistical detection of ovulation-linked behavioral fluctuations

Contention of the ovulatory shift hypothesis is principally supported by failures to replicate previous findings; e.g., recent meta-analytic work suggests that the effects endorsing the hypothesis may not be robust. Some possible limitations in this and other ovulatory-effects research-that may contribute to such controversy arising-are: (a) use of error-prone methods for assessing target periods of fertility that are thought to be associated with behavioral shifts, and (b) use of between-subjects-as opposed to within-subjects-methods. In the current study we present both simulated and empirical research: (a) comparing the ability of between- and within-subject t-tests to detect cyclical shifts; (b) evaluating the efficacy of correlating estimated fertility overlays with potential behavioral shifts; and (c) testing the accuracy of counting methods for identifying windows of cycle fertility. While this study cannot assess whether the ovulatory shift hypothesis or other ovulatory-based hypotheses are tenable, it demonstrates how low power resulting from typical methods employed in the extant literature may be associated with perceived inconsistencies in findings. We conclude that to fully address this issue greater use of within-subjects methodology is needed.

Men With a Terminal Illness Relax Their Criteria for Facial Attractiveness

According to the life history paradigm, in life-threatening conditions, sexual selection criteria are relaxed in order to increase the probability of a last resort reproduction, ultimately contributing to reproductive success. This should be reflected in loosened mating preferences — a process observed in nonhuman animals. Studies investigating this aspect in humans, however, are scarce. This study explored the aesthetic preferences towards facial and nonfacial stimuli in terminally ill patients with heart failure (HF) and their healthy, same-sex peers. The aim was to examine if these two groups of men demonstrate different patterns of aesthetic judgments. Using a 7-point scale, 65 male patients with HF and 143 healthy men evaluated the perceived attractiveness of 15 photographs (five adult male faces, five adult female faces, and five nonfacial pictures). A mixed-design analysis of variance was run to assess group differences in aesthetic preferences. Compared to healthy controls, stimuli. HF patients rated the pictures using significantly higher scores, but this applied only to male and female, but not nonfacial, stimuli. We propose that lower criteria for facial attractiveness in HF patients are linked to relaxation of mate preferences as a result of a life-threatening conditions, and that this process can be an adaptive mating strategy from an ultimate, evolutionary perspective. However, other mechanisms (e.g., seeking social support) may be also responsible for the observed patterns.

Endocrinology of human female sexuality, mating, and reproductive behavior

Hormones orchestrate and coordinate human female sexual development, sexuality, and reproduction in relation to three types of phenotypic changes: life history transitions such as puberty and childbirth, responses to contextual factors such as caloric intake and stress, and cyclical patterns such as the ovulatory cycle. Here, we review the endocrinology underlying women's reproductive phenotypes, including sexual orientation and gender identity, mate preferences, competition for mates, sex drive, and maternal behavior. We highlight distinctive aspects of women's sexuality such as the possession of sexual ornaments, relatively cryptic fertile windows, extended sexual behavior across the ovulatory cycle, and a period of midlife reproductive senescence-and we focus on how hormonal mechanisms were shaped by selection to produce adaptive outcomes. We conclude with suggestions for future research to elucidate how hormonal mechanisms subserve women's reproductive phenotypes.

Are physiological and behavioral immune responses negatively correlated? Evidence from hormone-linked differences in men's face preferences

Behaviors that minimize exposure to sources of pathogens can carry opportunity costs. Consequently, how individuals resolve the tradeoff between the benefits and costs of behavioral immune responses should be sensitive to the extent to which they are vulnerable to infectious diseases. However, although it is a strong prediction of this functional flexibility principle, there is little compelling evidence that individuals with stronger physiological immune responses show weaker behavioral immune responses. Here we show that men with the combination of high testosterone and low cortisol levels, a hormonal profile recently found to be associated with particularly strong physiological immune responses, show weaker preferences for color cues associated with carotenoid pigmentation. Since carotenoid cues are thought to index vulnerability to infectious illnesses, our results are consistent with the functional flexibility principle's prediction that individuals with stronger physiological immune responses show weaker behavioral immune responses.

Women's Fertility Status Alters Other Women's Jealousy and Mate Guarding

Across three studies, we tested the hypothesis that women exhibit greater jealousy and mate guarding toward women who are in the high (vs. low) fertility phase of their cycle. Women who imagined their partner with a woman pictured at high fertility reported more jealousy than women who imagined their partner with a woman pictured at low fertility (Studies 1 and 2). A meta-analysis across studies manipulating fertility status of the pictured woman found a significant effect of fertility status on both jealousy and mate guarding. Women with attractive partners viewed fertile-phase women as less trustworthy, which led to increased mate guarding (Study 2). In Study 3, the closer women were to peak fertility, the more instances they reported of other women acting jealously and mate guarding toward them. These studies provide evidence that women selectively exhibit jealousy and mate guarding toward women who are near peak fertility.

Lack of support for relation between woman's masculinity preference, estradiol level and mating context

It has been proposed that women's preferences for male facial sexual dimorphism are positively correlated with conception probability and differ between short- and long-term mating contexts. In this study, we tested this assumption by analyzing relationships between estradiol levels to the women's preferences of male faces that were manipulated to vary in masculinity. Estradiol was measured in daily saliva samples throughout the entire menstrual cycle collected by Polish women with regular menstrual cycles. In our analyses, we included the three most commonly used definitions of the fertile window in the literature. After computing the overall masculinity preference of each participant and measuring hormone levels, we found that i) the timing of ovulation varied greatly among women (between -11 and -17days from the onset of the next menses, counting backwards), ii) there was no relationship between daily, measured during the day of the test (N=83) or average for the cycle (N=115) estradiol levels and masculinity preferences, iii) there were no differences in masculinity preferences between women in low- and high-conception probability phases of the cycle, and iv) there were no differences in masculinity preferences between short- and long-term mating contexts. Our results do not support the idea that women's preferences for a potential sexual partner's facial masculinity fluctuate throughout the cycle.

Stress responses to repeated exposure to a combined physical and social evaluative laboratory stressor in young healthy males

Repeated exposure to homotypic laboratory psychosocial stressors typically instigates rapid habituation in hypothalamic-pituitary-adrenal (HPA) axis-mediated stress responses in humans. However, emerging evidence suggests the combination of physical stress and social evaluative threat may be sufficient to attenuate this response habituation. Neuroendocrine, cardiovascular and subjective stress responses following repeated exposure to a combined physical and social evaluative stress protocol were assessed to examine the habituation response dynamic in this context. The speech task of the Trier social stress test (TSST; Kirschbaum et al., 1993) and the socially evaluated cold pressor task (SECPT; Schwabe et al., 2008) were administered in a combined stressor protocol. Salivary cortisol, cardiovascular and subjective stress responses to a non-stress control and repeat stressor exposure separated by six weeks were examined in males (N=24) in a crossover manner. Stressor exposure resulted in significant elevations in all stress parameters. In contrast to the commonly reported habituation in cortisol response, a comparable post-stress response was demonstrated. Cortisol, heart rate and subjective stress responses were also characterised by a heightened response in anticipation to repeated stress exposure. Blood pressure responses were comparatively uniform across repeated exposures. Findings suggest a combined physical and social evaluative stressor is a potentially useful method for study designs that require repeated presentation of a homotypic stressor.

Does human ejaculate quality relate to phenotypic traits?

A given man's phenotype embodies cues of his ancestral ability to effectively defend himself and his kin from harm, to survive adverse conditions, and to acquire status and mating opportunities. In this review, we explore the hypothesis that a man's phenotype also embodies cues to fertility or the probability that an ejaculate will fertilize ova. Female mate choice depends on the ability to discern the quality of a male reproductive partner through his phenotype, and male fertility may be among the traits that females have evolved to detect. A female who selects as mates males that deliver higher quality ejaculates will, on average, be more fecund than her competitors. Data on several non-human species demonstrate correlations between ejaculate quality and secondary sexual characteristics that inform female mate choice, suggesting that females may select mates in part on the basis of fertility. While the non-human literature on this topic has advanced, the human literature remains limited in scope and there is no clear consensus on appropriate methodologies or theoretical positions. We provide a comprehensive review and meta-analysis of this literature, and conclude by proposing solutions to the many issues that impede progress in the field. In the process, we hope to encourage interest and insight from investigators in other areas of human mating and reproductive biology. Am. J. Hum. Biol. 28:318-329, 2016. © 2015 Wiley Periodicals, Inc.

Cooperative preferences fluctuate across the menstrual cycle

Social Value Orientation (SVO) refers to an individual’s preference for the division of resources between the self and another person. Since evidence suggests that hormones influence several facets of human social behavior, we asked whether SVO might fluctuate across the female menstrual cycle. Using self-report data obtained in two independent online studies, we show that cooperative preferences, as indexed by SVO, are indeed significantly more prosocial in the early follicular compared to the midluteal phase in naturally ovulating women. Furthermore, when estimating hormonal variations from norm data, we found estradiol, but not progesterone or testosterone, to be a significant predictor of SVO across the menstrual cycle in both studies, with a negative correlation. Our findings provide evidence that the willingness to cooperate varies across the natural female menstrual cycle and highlight the potential of investigating psychological effects of ovarian sex hormones.

Lady in Red

Recent evidence supports the idea that women use red clothing as a courtship tactic, and results from one study further suggested that women were more likely to wear red on days of high fertility in their menstrual cycles. Subsequent studies provided mixed support for the cycle-phase effect, although all such studies relied on counting methods of cycle-phase estimation and used between-subjects designs. By comparison, in the study reported here, we employed frequent hormone sampling to more accurately assess ovulatory timing and used a within-subjects design. We found that women were more likely to wear red during the fertile window than on other cycle days. Furthermore, within-subjects fluctuations in the ratio of estradiol to progesterone statistically mediated the within-subjects shifts in red-clothing choices. Our results appear to represent the first direct demonstration of specific hormone measurements predicting observable changes in women’s courtship-related behaviors. We also demonstrate the advantages of hormonal determination of ovulatory timing for tests of cycle-phase shifts in psychology or behavior.

Changes in Women's Facial Skin Color over the Ovulatory Cycle are Not Detectable by the Human Visual System

Human ovulation is not advertised, as it is in several primate species, by conspicuous sexual swellings. However, there is increasing evidence that the attractiveness of women's body odor, voice, and facial appearance peak during the fertile phase of their ovulatory cycle. Cycle effects on facial attractiveness may be underpinned by changes in facial skin color, but it is not clear if skin color varies cyclically in humans or if any changes are detectable. To test these questions we photographed women daily for at least one cycle. Changes in facial skin redness and luminance were then quantified by mapping the digital images to human long, medium, and shortwave visual receptors. We find cyclic variation in skin redness, but not luminance. Redness decreases rapidly after menstrual onset, increases in the days before ovulation, and remains high through the luteal phase. However, we also show that this variation is unlikely to be detectable by the human visual system. We conclude that changes in skin color are not responsible for the effects of the ovulatory cycle on women's attractiveness.

Experimenter Effects on Pain Reporting in Women Vary across the Menstrual Cycle

Background. Separate lines of research have shown that menstrual cycling and contextual factors such as the gender of research personnel influence experimental pain reporting. Objectives. This study examines how brief, procedural interactions with female and male experimenters can affect experimentally reported pain (cold pressor task, CPT) across the menstrual cycle. Methods. Based on the menstrual calendars 94 naturally cycling women and 38 women using hormonal contraceptives (M age = 19.83,  SD = 3.09) were assigned to low and high fertility groups. This assignment was based on estimates of their probability of conception given their current cycle day. Experimenters (12 males, 7 females) engaged in minimal procedural interactions with participants before the CPT was performed in solitude. Results. Naturally cycling women in the high fertility group showed significantly higher pain tolerance (81 sec, d = .79) following interactions with a male but not a female experimenter. Differences were not found for women in the low fertility or contraceptive groups. Discussion. The findings illustrate that menstrual functioning moderates the effect that experimenter gender has on pain reporting in women. Conclusion. These findings have implications for standardizing pain measurement protocols and understanding how basic biopsychosocial mechanisms (e.g., person-perception systems) can modulate pain experiences.

Waist-to-Hip Ratio, but Not Body Mass Index, Is Associated with Testosterone and Estradiol Concentrations in Young Women

We studied if testosterone and estradiol concentrations are associated with specific female waist-to-hip ratios (WHRs) and body mass indices (BMIs). Participants were 187 young women from which waist, hips, weight, and height were measured. In addition, participants informed on which day of their menstrual cycle they were and provided a 6 mL saliva sample. Ninety-one of them were in the follicular phase and 96 in the luteal phase. Only in the fertile phase of the menstrual cycle we found a significant interaction between testosterone and estradiol affecting WHR (b ± s.e. = -0.000003 ± 0.000001;  t 94 = -2.12, adjusted R (2) = -0.008,  P = 0.03). Women with the highest levels of both hormones had the lowest WHRs, while women with low estradiol and high testosterone showed the highest WHRs. BMI significantly increased as testosterone increased in female in their nonfertile days.

The reward value of infant facial cuteness tracks within-subject changes in women's salivary testosterone

"Baby schema" refers to infant characteristics, such as facial cues, that positively influence cuteness perceptions and trigger caregiving and protective behaviors in adults. Current models of hormonal regulation of parenting behaviors address how hormones may modulate protective behaviors and nurturance, but not how hormones may modulate responses to infant cuteness. To explore this issue, we investigated possible relationships between the reward value of infant facial cuteness and within-woman changes in testosterone, estradiol, and progesterone levels. Multilevel modeling of these data showed that infant cuteness was more rewarding when women's salivary testosterone levels were high. Moreover, this within-woman effect of testosterone was independent of the possible effects of estradiol and progesterone and was not simply a consequence of changes in women's cuteness perceptions. These results suggest that testosterone may modulate differential responses to infant facial cuteness, potentially revealing a new route through which testosterone shapes selective allocation of parental resources.