Ovulatory shifts in human female ornamentation: near ovulation, women dress to impress

The effects of power posing on neuroendocrine levels and risk-taking

BACKGROUND

The current study attempted to replicate the original findings regarding the effects of power posing on testosterone and cortisol levels, risk-taking behavior, and perceived power. We further extended the investigation by testing the effect of power posing on estradiol and progesterone levels.

METHODS

A sample of 92 young adults (30 males; 32 females taking oral contraceptives; and 30 females not taking oral contraceptives who were in their midluteal phase) were randomly assigned to high-power-pose or low-power-pose conditions and asked about their feelings of power. They completed a risk-taking task, and their neuroendocrine levels were measured both at baseline and following the power manipulation.

RESULTS

Power posing was not found to replicate the original results regarding effects on testosterone levels or feelings of power; however, our findings partially supported the original results regarding effects on cortisol levels and risk-taking. Among high-power posers, a decrease in cortisol levels was associated with risk tolerance. Power posing was not found to influence progesterone levels. However, among females taking oral contraceptives, high-power posing increased estradiol levels.

CONCLUSIONS

These preliminary findings suggest that estradiol is influenced by short-term exposure to social cues under specific hormonal profiles.

Effect of the red uniform on the judgment of position or movement used in Wushu Routine, evaluated by practitioners of the modality

In the artistic sports program, the referee' scores directly determine the final results of the athletes. Wushu is a artistic sport that has a Chinese characteristic and has the potential to become an official competition at the Summer Olympic. In this study we tested whether a red uniform color affects Wushu Routine practitioners' ratings of athletes' position or movement of Wushu Routine. We also tested whether the effect varied depending on the gender of the athlete and the practitioner, and depending on whether female practitioners were in the ovulation phase of their menstrual cycle. Male (Experiment 1: N = 72) and female (Experiment 1: N = 72; Experiment 2: N = 52) participants who major in Wushu Routine were recruited to take a referee's perspective and rate the movement quality of male and female athletes wearing red or blue uniforms. The results of Experiment 1 showed that both male and female athletes wearing red uniform (compared to blue uniform) received higher ratings (p = .002, η2 = .066; p = .014, η2 = .043), and the red effect was especially strong when male practitioners rated female athletes (p = .002, η2 = .069). The results of Experiment 2, in an all-female sample, showed that in most cases there was no difference in ratings made by women in the ovulation and non-ovulation phases of their menstrual cycle, with the exception of their ratings of male athletes wearing red; in this condition, women gave higher ratings when they were in the ovulation phase of their cycle (p = .026). The results suggest that there is a red effect in an artistic sport like Wushu Routine, in which gender and the female menstrual cycle play an important role.

Investigating cycle shifts in women's clothing style and grooming

In contrast to some non-human primate species, human females do not show overt cues to fertility. Previous research argued that women still show systematic changes in their appearance across their ovulatory cycle to enhance their mating success when fertile. We report five studies investigating whether women's clothing style and grooming behaviour change across the ovulatory cycle. All studies were large (with N = 157 in Study 1, N = 109 in Study 2, N = 257 in Studies 3-5), longitudinal studies with four testing sessions per participant. They involved salivary hormone samples and luteinizing hormone tests to validate conception risk estimates. Across all studies, our results suggest no compelling evidence for cycle shifts in clothing style and grooming. Rather, two studies suggest effects in the opposite direction as hypothesized, as women wore more skin-revealing clothes when non-fertile. One study suggests small effects of wearing necklaces more and eyeglasses less often when fertile. However, these effects were not robust across all studies. Our results are in line with other recent null replications and suggest that, if existent, cues to fertility might be even more subtle than previously assumed. We discuss the need for testing competing theories that explain the evolution of concealed ovulation.

Tendencies Toward Supernormality/Subnormality in Generating Attractive and Unattractive Female and Male Avatars: Gender Differences

In the present study, we investigated the differences in the experience of attractiveness and unattractiveness of human bodies. A total of 101 participants (55 females) were asked to create the most attractive and the most unattractive female and male figures using a computer animation. They performed this task by adjusting the size of six body parts: shoulders, breasts/chest, waist, hips, buttocks, and legs. Analyses indicated that attractive body parts were distributed normally with the peak shifted to moderately supernormal sizes, while unattractive body parts had mostly U-shaped or skewed distributions with extremes in super-supernormal and/or subnormal sizes. Generally, both male and female attractive bodies had prominent "sporty" look: supernormally wide shoulders and long legs. Gender differences showed that men prefer more supernomal masculine and feminine sizes, while women show an ambivalence toward both groups of traits. Principal components analysis revealed gender differences on the multitrait level: males focus on prominent masculine and feminine traits, while women focus on traits that make both male and female bodies more elongated and slender. Gender differences were in line with specific male and female positions in the partner selection process, while a certain tendency toward masculinization of the female body required the inclusion of social factors, such as the influence of the culture of a sporty and fit look.

A review and p-curve analysis of research on the menstrual cycle correlates of consumer preferences and economic decisions

A number of studies have been claimed to show that ovarian hormones, whose levels fluctuate throughout the menstrual cycle, affect consumer preferences and financial decisions. The present article aims to critically analyze the literature examining associations between the phases of the menstrual cycle (peri-ovulatory vs. non-ovulatory) with particular consumer preferences (especially regarding clothing choices) and economic decisions (especially in regards to economic games and risk-taking). A search for studies was conducted in Web of Science and Scopus between 2004 and 2022, by combining keywords of the menstrual cycle, consumer preferences, and economic decisions. Once articles were selected, we identified the main findings, the characteristics of the population, and the methods for determining the phases of the cycle. We performed a p-curve analysis on previously reported statistically significant effects. These analyses find evidence for associations between peri-ovulatory status and specific consumer preferences, most strongly for appearance-enhancing products. They yield no compelling evidence for associations between peri-ovulatory status and financial decisions and risk-taking. We offer provisional conclusions and call for additional studies that possess sufficient statistical power to detect true meaningful effects, especially in the domain of financial decisions.

Economic Decisions, Attractiveness, and Intrasexual Competition during Menstrual Cycle in the Ultimatum Game

Introduction

it seems that, in the phase of greatest fertility, women's intrasexual competition (toward attractive women who live nearby) increases due to access to resources, status, and biologically desirable partners.

Objective

to compare the economic decisions (ED) during the ovulatory (OP) and luteal (LP) phases of the menstrual cycle (MC) with exposure to two stimuli: a photograph of a more attractive woman and a photograph of a less attractive woman, through the ultimatum game (UG).

Methodology

the research followed a cross-sectional design between subjects to see group differences by contrasting hypotheses. The sampling was probabilistic, with a sample of 100 heterosexual women, students at a public university with an age range of 18 to 24 years, with regular MC, who did not use hormonal contraceptive methods and did not have any endocrine condition. The inverse counting method with confirmation was applied to identify CM phases; and the UG to evaluate the DE.

Results

the phases of the MC had no effect on the ED; the women behaved similarly in their decisions, regardless of the phase of the cycle they were in or the type of stimulus to which they were exposed.

Conclusion

OP and LP do not affect the ED of women when they are exposed to an attractive stimulus. The discussion is made considering the evolutionary theory of the ovulatory shift hypothesis.

When fertile, women seek status via prestige but not dominance

Biological predictors of human dominance are hotly contested, with far-reaching implications for psychological sex differences and the placement of men and women in the social hierarchy. Most investigations have focused on dominance in men and testosterone, with diminished attention paid to dominance in women and other biological mechanisms. Investigating biological influences on other routes to status attainment popular among women-such as via prestige in addition to dominance-have also been neglected. Here, I examined whether status seeking via prestige and via dominance covaried with fertility probability in a citizen science project spanning 14 countries and 4 world regions. Across 4,179 observations, participants tracked their menstrual cycle characteristics, motivation for prestige and dominance, dominance contest outcomes, and three domains of self-esteem. Self-esteem is predicted by status within a group and helps individuals navigate social hierarchies. Bayesian mixed models controlling for menstruation indicated that the motivation to obtain status via prestige but not dominance peaked when conception was most likely, as did dominance contest losses and two self-esteem domains. Fertility appears to reorient female psychology toward prestige-based strategies to success, enhancing women's desire for social capital through influence and admiration but not through fear, coercion, or intimidation. These insights fundamentally advance the understanding of the biological correlates of status seeking among women. They further suggest that fertility motivates not only mating competition but gaining rank and positive regard in social hierarchies.

Women’s Intrasexual Competitiveness and Jealousy Across the Ovulatory Cycle: A Hormone-Based Study

Research on social status competition among women suggests that underlying hormonal shifts associated with the ovulatory cycle systematically drive alterations in preferences and behavior. Specifically, it is proposed that the fertile window, marked by heightened estradiol and lower progesterone levels, is related to increased psychological motivation for intrasexual social comparison, leading to increasing competitiveness and jealousy. In this pre-registered, longitudinal study, 257 women provided saliva samples for hormone assays, rated the attractiveness of other women, and self-reported intrasexual competitiveness and jealousy across four testing sessions. Multilevel analyses revealed no compelling evidence for (hormone-related) cycle shifts in intrasexual competitiveness, attractiveness ratings, or jealousy. Rather, women higher in intrasexual competitiveness seem to rate other women as more attractive in general. We discuss how our results contribute to a growing body of literature suggesting that women’s social attitudes and preferences are more stable and less hormonally influenced than previously assumed.

Discounting for Money, Food, and Sex, over the Menstrual Cycle

Sexual desire, physical activity, economic choices and other behaviours fluctuate over the menstrual cycle. However, we have an incomplete understanding of how preferences for smaller sooner or larger later rewards (known as delay discounting) change over the menstrual cycle. In this pre-registered, cross-sectional study, Bayesian linear and quadratic binomial regression analyses provide compelling evidence that delay discounting does change over the menstrual cycle. Data from 203 naturally cycling women show increased discounting (preference for more immediate rewards) mid-cycle, which is at least partially driven by changes in fertility. This study provides evidence for a robust and broad-spectrum increase in delay discounting (Cohen’s h ranging from 0.1 to 0.4) around the fertile point in the menstrual cycle across multiple commodities (money, food, and sex). We also show, for the first time, that discounting changes over the menstrual cycle in a pseudo-control group of 99 women on hormonal contraception. Interestingly, such women increase their discounting of sex toward the end of the menstrual phase — possibly reflecting a prioritisation of bonding-related sexual activity before menstrual onset.

Men are not aware of and do not respond to their female partner's fertility status: Evidence from a dyadic diary study of 384 couples

Understanding how human mating psychology is affected by changes in female cyclic fertility is informative for comprehending the evolution of human reproductive behavior. Based on differential selection pressures between the sexes, men are assumed to have evolved adaptations to notice women's within-cycle cues to fertility and show corresponding mate retention tactics to secure access to their female partners when fertile. However, previous studies suffered from methodological shortcomings and yielded inconsistent results. In a large, preregistered online dyadic diary study (384 heterosexual couples), we found no compelling evidence that men notice women's fertility status (as potentially reflected in women's attractiveness, sexual desire, or wish for contact with others) or display mid-cycle increases in mate retention tactics (jealousy, attention, wish for contact or sexual desire towards female partners). These results extend our current understanding of the evolution of women's concealed ovulation and oestrus, and suggest that both might have evolved independently.

Hormonal contraceptives as disruptors of competitive behavior: Theoretical framing and review

Emerging evidence suggests that hormonal contraceptives (HCs) impact psychological outcomes through alterations in neurophysiology. In this review, we first introduce a theoretical framework for HCs as disruptors of steroid hormone modulation of socially competitive attitudes and behaviors. Then, we comprehensively examine prior research comparing HC users and non-users in outcomes related to competition for reproductive, social, and financial resources. Synthesis of 46 studies (n = 16,290) led to several key conclusions: HC users do not show the same menstrual cycle-related fluctuations in self-perceived attractiveness and some intrasexual competition seen in naturally-cycling women and, further, may show relatively reduced status- or achievement-oriented competitive motivation. However, there a lack of consistent or compelling evidence that HC users and non-users differ in competitive behavior or attitudes for mates or financial resources. These conclusions are tentative given the notable methodological limitations of the studies reviewed. Implications and recommendations for future research are discussed.

Enhanced Originality of Ideas in Women During Ovulation: A Within-Subject Design Study

The signaling theory suggests that creativity may have evolved as a signal for mates. Indeed, its aesthetic value might not have been necessary for survival, but it could have helped to attract a mate, fostering childbearing. If we consider creativity as such a signal, we should expect it will be enhanced in the context related to sexual selection. This hypothesis was tested mainly for men. However, both men and women display physical and mental traits that can attract a mate. Previous studies showed that women can be more creative during their peak fertility. We advanced these findings in the present study, applying reliable measures of menstrual cycle phases (examining saliva and urine samples) and the highly recommended within-subject design. We also introduced and tested possible mediators of the effect. We found women’s ideas to be more original during ovulation compared to non-fertile phases of the ovulatory cycle. The results are discussed in the context of signaling theory and alternative explanations are considered.

Chemical cues of identity and reproductive status in Japanese macaques

Olfactory communication plays an important role in the regulation of socio-sexual interactions in mammals. There is growing evidence that both human and nonhuman primates rely on odors to inform their mating decisions. Nevertheless, studies of primate chemical ecology remain scarce due to the difficulty of obtaining and analyzing samples. We analyzed 67 urine samples from five captive female Japanese macaques (Macaca fuscata) and 30 vaginal swabs from three of these females using gas chromatography-mass spectrometry and examined the relationship between odor (compounds identified, richness, intensity, and diversity) and female identity as well as cycle phase. We found a total of 36 urine compounds of which we identified 31, and 68 vaginal compounds of which we identified 37. Our results suggest that urine and vaginal odor varied more between individuals than within cycle phases. However, we found that within a female cycle, urine samples from similar phases may cluster more than samples from different phases. Our results suggest that female odor may encode information about identity (vaginal and urine odor) and reproductive status (urine odor). The question of how conspecifics use female urine and vaginal odor remains open and could be tested using bioassays. Our results and their interpretation are constrained by our limited sample size and our study design. Nonetheless, our study provides insight into the potential signaling role of female odor in sexual communication in Japanese macaques and contributes to our understanding of how odors may influence mating strategies in primates.

Oxytocin Reduces the Attractiveness of Silver-Tongued Men for Women During Mid-Cycle

In humans, the neuropeptide oxytocin promotes both attraction toward and bonds with romantic partners, although no studies have investigated whether this extends to the perceived attractiveness of flirtatious language. In a within-subject, randomized double-blind placebo-controlled behavior and functional magnetic resonance imaging (fMRI) paradigm (https://clinicaltrials.gov/show/NCT03144115), 75 women rated the attractiveness of either a male face alone or paired with a verbal compliment which varied in terms of topic (women or landscapes) and figurativeness (novel or conventional metaphors or literal expressions). Subjects were tested in fertile and luteal phases of their cycle and on both occasions received either 24 IU intranasal oxytocin or placebo. Results showed that, whereas under placebo women in the fertile phase rated the facial attractiveness of men producing novel metaphorical compliments higher than in their luteal phase, following oxytocin treatment they did not. Correspondingly, under oxytocin the faces of individuals producing novel metaphorical compliments evoked greater responses in brain regions involved in processing language (middle frontal gyrus) and cognitive and emotional conflict (posterior middle cingulate and dorsal anterior cingulate) but reduced functional connectivity between the dorsal anterior cingulate and right orbitofrontal and medial frontal gyri. Thus, sex hormones and oxytocin may have opposite effects in regulating mate selection in women during their fertile phase. Novel metaphorical compliments convey a greater sexual than bonding intention and thus while sex hormones at mid-cycle may promote attraction to individuals communicating sexual rather than bonding intent, oxytocin may bias attraction away from such individuals through increasing cognitive and emotional conflict responses toward them.

An Evolutionary Perspective on Appearance Enhancement Behavior

Researchers have highlighted numerous sociocultural factors that have been shown to underpin human appearance enhancement practices, including the influence of peers, family, the media, and sexual objectification. Fewer scholars have approached appearance enhancement from an evolutionary perspective or considered how sociocultural factors interact with evolved psychology to produce appearance enhancement behavior. Following others, we argue that evidence from the field of evolutionary psychology can complement existing sociocultural models by yielding unique insight into the historical and cross-cultural ubiquity of competition over aspects of physical appearance to embody what is desired by potential mates. An evolutionary lens can help to make sense of reliable sex and individual differences that impact appearance enhancement, as well as the context-dependent nature of putative adaptations that function to increase physical attractiveness. In the current review, appearance enhancement is described as a self-promotion strategy used to enhance reproductive success by rendering oneself more attractive than rivals to mates, thereby increasing one's mate value. The varied ways in which humans enhance their appearance are described, as well as the divergent tactics used by women and men to augment their appearance, which correspond to the preferences of opposite-sex mates in a heterosexual context. Evolutionarily relevant individual differences and contextual factors that vary predictably with appearance enhancement behavior are also discussed. The complementarity of sociocultural and evolutionary perspectives is emphasized and recommended avenues for future interdisciplinary research are provided for scholars interested in studying appearance enhancement behavior.

Factors Influencing Sexual Vocalization in Human Females

Human females use numerous signals to attract male attention which can be ultimately motivated by enhanced paternal investment in the offspring. Sexual vocalization is a form of female sexual signaling. The majority of hypotheses attempting to explain the functional significance of vocalizations have been applied on non-human primates, while research on human females is scarce. This study investigated factors underlying sexual vocalization with a sample of 403 heterosexual Slovak females. Sexual vocalization was most frequent during penetration itself compared with other forms of sexual activities, which supports its signaling function. The most frequently reported sexual vocalizations were moaning/groaning, followed by screams and instructional commands, squeals, and words. Both the frequency and intensity of sexual vocalizations were significantly and positively associated with sexual arousal during the last sexual vaginal intercourse and sociosexuality. About 38% of females reported that they pretended vocalization and, in turn, pretended vocalization was exclusively associated with pretending orgasm. No direct evidence was found for any associations between self-reported frequency and intensity of sexual vocalization and partner satisfaction/physical attractiveness/ambition/dominance, self-perceived attractiveness, or occurrence of orgasm. The frequency (but not intensity) of sexual vocalization was positively influenced by the conception risk. On the proximate level, it seems that sexually less restricted females may use sexual vocalization to increase their sexual attractiveness to their current partner by means of boosting their partner's self-esteem. Enhanced vocalization by sexually unrestricted females may ultimately secure higher paternal investment and increase the confidence of the paternity of current sexual partner.

Women feel more attractive before ovulation: evidence from a large-scale online diary study

How attractive we find ourselves decides who we target as potential partners and influences our reproductive fitness. Self-perceptions on women's fertile days could be particularly important. However, results on how self-perceived attractiveness changes across women's ovulatory cycles are inconsistent and research has seldomly assessed multiple attractiveness-related constructs simultaneously. Here, we give an overview of ovulatory cycle shifts in self-perceived attractiveness, sexual desirability, grooming, self-esteem and positive mood. We addressed previous methodological shortcomings by conducting a large, preregistered online diary study of 872 women (580 naturally cycling) across 70 consecutive days, applying several robustness analyses and comparing naturally cycling women with women using hormonal contraceptives. As expected, we found robust evidence for ovulatory increases in self-perceived attractiveness and sexual desirability in naturally cycling women. Unexpectedly, we found moderately robust evidence for smaller ovulatory increases in self-esteem and positive mood. Although grooming showed an ovulatory increase descriptively, the effect was small, failed to reach our strict significance level of .01 and was not robust to model variations. We discuss how these results could follow an ovulatory increase in sexual motivation while calling for more theoretical and causally informative research to uncover the nature of ovulatory cycle shifts in the future.

Sex-Differentiated Attire’s Impact on Individual Action and Mate Selection

Various theories highlight the importance of using the actor/environment as the ideal unit for theoretical and experimental focus. Clothing, placed as it is as the intermediary between body and environment, is typically treated as a symbol rather than as either an integral part of either the body or the environment. When clothing is considered an extension of the body, the historical development of clothing reflects persistent differences in the physical capabilities of the human animal and operates as an instrument for solo action. In addition, it is argued that due to the ecological mechanisms connecting perception and action, differential clothing options for the sexes has led in no small part to differences in self-perception as well as the perception of others. However, when it comes to the very specific behavior of mate selection and procreation, clothing can be understood as a tether between two systemic units, offering a description of a system that allows for communication of potential social affordances and opportunities for joint action.

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.

The More Fertile, the More Creative: Changes in Women's Creative Potential across the Ovulatory Cycle

Creative thinking is a defining human feature. It provides novel solutions and as such undoubtedly has contributed to our survival. However, according to signaling theory, creativity could also have evolved through sexual selection as a potential fitness indicator. In our study, we tested one implication of this theory. Specifically, we hypothesized that if creativity can serve as a signal of women’s fitness, then we should observe an increase in creative thinking in the fertile phase of the ovulatory cycle compared to other non-fertile phases. In our study (N = 751), we tested creative potential throughout the ovulatory cycle. We found a positive correlation between the probability of conception and both creative originality and flexibility. Importantly, we also tested the mediating role of arousal in the relationship between the probability of conception and creative thinking. The results of our study are discussed in terms of signaling theory, through which women advertise their fitness with their creativity.

Primary dysmenorrhea and postural control: Is it a problem only during menstruation?

BACKGROUND

The effects of the menstrual cycle and primary dysmenorrhea (PD) on phase-related cognitive and physical functions are controversial. This study was carried out to examine whether women with PD showed a different physical function or dual-tasking response than women without PD at times other than menstruation.

METHODS

Women with or without PD were recruited for the study. Individuals assessed on the first day of the menstruation and the day they reported themselves as well being (feeling good day-FGD). Zebris © FDM Type Force Platform was used to evaluate postural stability. Individuals have were asked to perform to a 3-step balance test protocol; the first session: comfortable upright standing; the second session: standing with a motor task; the third session: standing with a cognitive task (counting backward). Correctly calculated numbers were also recorded.

RESULTS

The number of correct answers given by individuals during the cognitive dual-task was similar on the first day of menstruation and FGD (p > 0.05). In the control group, no difference was observed between the first days of menstruation and the evaluations on FGD days with dual-task (p > 0.05). In individuals with PD, there was no difference between the measurements at different times (p > 0.05). However, in the assessment with the motor dual-task on the first day of menstruation; postural sway increased (p < 0,05). In FDG measurement; distortion in postural stability was observed with the cognitive task (p < 0,05). In the assessments performed on the first day of menstruation, there was no difference in any parameters between the groups (p > 0.05). In the measurements made on FGD day with the cognitive task; there was a difference between the groups (p < 0,05). Individuals with PD had higher postural sway.

SIGNIFICANCE

This study showed that the primary dysmenorrhea is not only a problem for females during menstruation, primary dysmenorrhea causes impaired ability of the individual to perform dual-tasking and continuously affects postural stability.

Evidence for conditional sex differences in emotional but not in sexual jealousy at the automatic level of cognitive processing

The two evolutionary psychological hypotheses that men react more jealous than women to sexual infidelity and women react more jealous than men to emotional infidelity are currently controversial because of apparently inconsistent results. We suggest that these inconsistencies can be resolved when the two hypotheses are evaluated separately and when the underlying cognitive processes are considered. We studied jealousy with forced‐choice decisions and emotion ratings in a general population sample of 284 adults aged 20–30 years using six infidelity dilemmas and recordings of reaction times. The sex difference for emotional jealousy existed for decisions under cognitive constraint, was also evident in the decision speed, increased for faster decisions, and was stronger for participants with lower education. No evidence for a sex difference in sexual jealousy was found. Our results support the view of a specific female sensitivity to emotional infidelity that canalizes the development of an adaptive sex difference in emotional jealousy conditional to the sociocultural environment. Copyright © 2007 John Wiley & Sons, Ltd.

Content matters: Cyclic effects on women's voices depend on social context

Women's voices reportedly sound more attractive during the fertile days compared to the non-fertile days of their menstrual cycle. Here we investigated whether the speech content modulates the cyclic changes in women's voices. We asked 72 men and women to rate how interested they were in getting to know the speaker based on her voice. Forty-two naturally cycling women were recorded once during the late follicular phase (high fertility) and once during the luteal phase (low fertility) while speaking sentences of neutral and social content. Listeners were more interested in getting to know the speakers when hearing sentences with social content. Furthermore, raters were more interested in getting to know the speakers when these were recorded in the late follicular than in the luteal phase, but only in sentences with social content. Notably, levels of reproductive hormones (EP ratio) across the cycle phases did not significantly predict the preference for late follicular voices, but echoing the perceptual ratings, there was a significant EP ratio x speech content interaction. Phonetic analyses of mean fundamental frequency (F0) revealed a main effect of menstrual cycle phase and speech content but no interaction. Employing an action-oriented task, the present study extends findings of cycle-dependent voice changes by emphasising that speech content critically modulates fertility effects.

Women's use of intimate apparel as subtle sexual signals in committed, heterosexual relationships

Current literature on women’s sexual signaling focuses on modes of attracting potential, new sexual partners, but says little about women’s subtle sexual signals in committed, romantic relationships. Subtle sexual signals are inherently private and are only visible to the intended audience; a woman might use these signals to elicit or accept a sexual response from her partner or to increase her overall attractiveness, or attractivity. In this study, we sought to identify women’s use of intimate apparel as a proceptive or receptive behavior as well as the effects of relative mate value, relationship commitment, relationship satisfaction, and sexual functioning. A total of N = 353 women in the United States aged 25–45 who were in committed, heterosexual relationships completed the survey; 88.7% of the sample indicated wearing or having worn sexy underwear. Results indicate that women report wearing sexier underwear the day taking the survey if they anticipate sexual activity that same day. However, during the most recent sexual activity, women did not report wearing sexier underwear if they initiated (proceptive) that activity. While relative mate value was not directly related to sexiness of intimate apparel, women who report higher mate value tend to wear sexier underwear. Women’s use of intimate apparel might be viewed as a method of increasing attractivity and underlying receptivity to aid relationship maintenance, though caveats regarding measures and alternative interpretations are also discussed. Findings suggest that these women use intimate apparel to feel sexy, desired, aroused, and to prepare for sex with their partners. This study is the first to examine intimate apparel in relationships and as a subtle sexual signal of proceptivity and receptivity.

Are women more likely to wear red and pink at peak fertility? What about on cold days? Conceptual, close, and extended replications with novel clothing colour measures

Evolutionarily minded researchers have hypothesized that women advertise their ovulatory status by wearing red or pink clothing on relatively cold days. Many of these studies have been based on samples of women who have self-reported their clothing choices, a practice that raises questions about accuracy. In two studies, we evaluated the relationship between women's fertility and their clothing choices using four methods for measuring clothing colour: self-reports; trained raters' judgements of garment coloration in outfits that women drew onto mannequins to represent what they would wear to a party with single attractive people in attendance; automated colour coding of the mannequins; and trained raters' judgements of garment coloration as evinced in photographs that women took of themselves. Using these four measures of clothing choice along with measures of women's fertility and outside temperature, we did not find compelling evidence that women are particularly inclined to wear red or pink during peak fertility, even on relatively cold days.

Women’s Strategic Defenses Against Same-Sex Aggression: Evidence From Sartorial Behavior

Women’s intrasexual competition has received significant attention only in the last decades, with even less work investigating women’s defenses against such aggression. Yet, we should expect that women can (a) grasp which perceptually-salient cues evoke same-sex aggression and (b) strategically damp the display of (some of) those cues when aggression risk is greatest, thereby avoiding the potentially high costs of victimization. Women selectively aggress against women displaying cues of sexual permissiveness (e.g., revealing dress) and/or desirability (e.g., physical attractiveness). We find that (a) women (and men) anticipate greater intrasexual aggression toward women dressed revealingly versus modestly, especially if targets are attractive. Employing behavioral and self-report measures, we also find (b) women create outfits baring less skin, select more modest clothing, and intend to dress less revealingly to encounter other women, flexibly damping permissiveness cues depending on individual features (physical attractiveness) and situational features (being a newcomer) that amplify aggression risk.

Chemical cues of female fertility states in a non-human primate

An increasing number of studies suggest that olfaction is important for communication throughout the order of primates. Callitrichids, in particular, have well-developed olfactory systems and use anogenital glands to produce scent marks. Behavioural studies have shown that male common marmosets (Callithrix jacchus) distinguish between odours from the peri-ovulatory and luteal phase of females. However, large gaps remain in understanding the chemical underpinnings of olfactory cues. To investigate whether chemical cues vary with female fertility and reproductive quality, our study combined behavioural bioassays with chemical analyses of the anogenital odours of female common marmosets using gas chromatography-mass spectrometry. We found that cycle states, age and parity have an impact on chemical profiles and further identified affected chemical substances. Our results confirm and expand on previous behavioural evidence for cues of fertility. Our results indicate that cycle-related substances likely act as chemical cues. Males could use such olfactory fertility cues to optimize their mating effort and thereby increase their paternity certainty. This certainty could enhance paternal care for their infants. The results of our study open a promising avenue to find the metabolic pathways from which chemical cues of fertility arise and to unravel their importance during primate evolution in future comparative studies.

Nicotinamide as Independent Variable for Intelligence, Fertility, and Health: Origin of Human Creative Explosions?

Meat and nicotinamide acquisition was a defining force during the 2-million-year evolution of the big brains necessary for, anatomically modern, Homo sapiens to survive. Our next move was down the food chain during the Mesolithic 'broad spectrum', then horticultural, followed by the Neolithic agricultural revolutions and progressively lower average 'doses' of nicotinamide. We speculate that a fertility crisis and population bottleneck around 40 000 years ago, at the time of the Last Glacial Maximum, was overcome by Homo (but not the Neanderthals) by concerted dietary change plus profertility genes and intense sexual selection culminating in behaviourally modern Homo sapiens. Increased reliance on the 'de novo' synthesis of nicotinamide from tryptophan conditioned the immune system to welcome symbionts, such as TB (that excrete nicotinamide), and to increase tolerance of the foetus and thereby fertility. The trade-offs during the warmer Holocene were physical and mental stunting and more infectious diseases and population booms and busts. Higher nicotinamide exposure could be responsible for recent demographic and epidemiological transitions to lower fertility and higher longevity, but with more degenerative and auto-immune disease.

Mating Effort Predicts Human Menstrual Cycle Frequency

The human menstrual cycle is characterized by substantial variability both within and between women. Here, we sought to account for such variability by examining whether human menstrual cycle frequency varies as a function of the projected fitness payoffs associated with investment in mating effort. We used structural equation modeling to test the prediction that women whose environmental conditions or life histories favor heavier investment in mating effort would have shorter, more regular cycles. Results supported our hypothesis, revealing that women who project more mating success and have faster life history strategies exhibit greater mating effort and shorter, more regular menstrual cycles. An alternative model that specified cycle frequency as a predictor of mating effort was a poor fit for the data, lending support for the hypothesized directionality of the path between these variables. Together, these results provide some of the first empirical evidence that the length and regularity of the human menstrual cycle may be calibrated to investment in mating effort.

Evidence That the Hormonal Contraceptive Pill Is Associated With Cosmetic Habits

Hormonal contraception is known to cause subtle but widespread behavioral changes. Here, we investigated whether changes in cosmetic habits are associated with use of the hormonal contraceptive pill. We photographed a sample of women (N = 36) who self-reported whether or not they use the contraceptive pill, as well as their cosmetic habits. A separate sample of participants (N = 143) rated how much makeup these target women appeared to be wearing. We found that women not using the contraceptive pill (i.e., naturally cycling women) reported spending more time applying cosmetics for an outing than did women who use the contraceptive pill. We also found that the faces of these naturally cycling women were rated as wearing more cosmetics than the faces of the women using the contraceptive pill. Thus, we found clear associations between contraceptive pill use and makeup use. This provides evidence consistent with the possibility that cosmetic habits, and grooming behaviors more generally, are affected by hormonal contraception.

Hormonal contraceptive affects heterosexual but not homosexual behavior in free-ranging female Japanese macaques over 17 mating seasons

We assessed the effect of a progestin-based contraceptive treatment (chlormadinone acetate) on female heterosexual and homosexual behaviors in a free-ranging group of Japanese macaques (Macaca fuscata) living at Arashiyama-Kyoto, Central Japan. The data included estimated intensity of fertility cues, sexual solicitations and mounting behaviors collected daily during 17 consecutive mating seasons (1995-2012) from 159 females. Females that were on contraception: (1) exhibited less intense cues of putative fertility and for shorter periods; (2) were solicited by fewer males, and those males that did solicit them did so less often (i.e., lower heterosexual attractivity); (3) solicited fewer males and when they did perform sexual solicitations they did so less often (i.e., lower heterosexual proceptivity); (4) engaged in shorter heterosexual consortships with fewer male partners (i.e., lower heterosexual receptivity), compared with females that were not on contraception. In contrast, contraceptive treatment had no significant effect on the prevalence, occurrence, frequency, or duration of female homosexual behaviors. Even though heterosexual and homosexual behaviors can both be considered sexual in character and under hormonal control, our results suggested they are, to some extent, dissociable. Because females engaging in homosexual interactions showed less intense cues of putative fertility than those engaging in heterosexual interactions, regardless of contraceptive treatment, we argued that the hormonal threshold required for the expression of heterosexual behavior by females was associated with elevated sex hormones levels compared to homosexual behavior. We discussed the hormonal correlates of sexual behavior and partner preferences in Japanese macaques.

Life History, Fertility, and Short-Term Mating Motivation

The current research examines the impact of women's early-life socioeconomic status (SES; used as a proxy measure of life history strategy), relationship status, and ovulatory cycle phase on their desire for short-term mating. Results revealed that during the periovulatory phase (i.e., the high-fertility phase of the monthly ovulatory cycle), single women from low SES environments expressed an increased desire for short-term mating, whereas the opposite was found for single women from high SES environments. No such pattern was found for partnered women. These results suggest that one's early-life environment and relationship status may play a key role in how women respond to internal fertility cues, providing important new insights into factors that may moderate ovulatory shifts in mating behavior. Results provide some of the first evidence that one's developmental history may alter the expression of ovulatory cycle adaptations.

Interactions between observer and stimuli fertility status: Endocrine and perceptual responses to intrasexual vocal fertility cues

Both men and women find female voices more attractive at higher fertility times in the menstrual cycle, suggesting the voice is a cue to fertility and/or hormonal status. Preference for fertile females' voices provides males with an obvious reproduction advantage, however the advantage for female listeners is less clear. One possibility is that attention to the fertility status of potential rivals may enable women to enhance their own reproductive strategies through intrasexual competition. If so, the response to having high fertility voices should include hormonal changes that promote competitive behavior. Furthermore, attention and response to such cues should vary as a function of the observer's own fertility, which influences her ability to compete for mates. The current study monitored variation in cortisol and testosterone levels in response to evaluating the attractiveness of voices of other women. All 33 participants completed this task once during ovulation then again during the luteal phase. The voice stimuli were recorded from naturally cycling women at both high and low fertility, and from women using hormonal birth control. We found that listeners rated high fertility voices as more attractive compared to low fertility, with the effect being stronger when listeners were ovulating. Testosterone was elevated following voice ratings suggesting threat detection or the anticipation of competition, but no stress response was found.

Humans as a model species for sexual selection research

Ever since Darwin, questions about humans have driven sexual selection research. While studies of other organisms are often justified as useful for improving understanding of humans, humans themselves can be useful models. Although humans present some drawbacks as model organisms (complicated societies, slow reproduction and strong ethical constraints on experimental options), humans nonetheless offer many advantages (being abundant, accessible and having detailed historical records for some populations). As an additional challenge, humans exhibit a rather puzzling combination of traits. Some traits (pair-bonding, biparental care and modest sexual dimorphism in body size) suggest selection for monogamous mating, while other traits (including sexual dimorphism in body composition and appearance) suggest selection for polygyny. Such puzzles have motivated research on other species, resulting in a rich set of comparative data that provides insights into humans and other species. Recent studies of visual trait dimorphism suggest that human appearance reflects adaptation for multi-level societies, rather than high levels of polygyny. In addition to biological traits, human cultural traits have undergone rapid evolution. Changes in subsistence strategies profoundly affect opportunities for sexual selection. The enormous variability of human behaviour and ecology provides abundant opportunities to test key hypotheses, and poses challenging puzzles for future research.

The Role of Ovarian Hormones and the Medial Amygdala in Sexual Motivation

Purpose

Although research into the neurobiology of sexual desire in women is active, relatively little is understood about the origins of sexual motivation in women. The purpose of our review is to discuss factors that influence a central sexual motivate state and generalized arousal as potential drivers of sexual motivation in women and female rats.

Recent Findings

Sexual motivation is the product of interactions of the central motive state and salient sexually-relevant cues. Ovarian hormones and generalized arousal influence the central motive state, and endogenous levels of estradiol and progesterone correlate with sexual motivation and behavior in women. The amygdala is a key integratory site for generalized arousal and sexual sensory stimulation, which could then increase sexual motivation through its downstream projections.

Summary

Our model of enhanced female sexual motivation suggests that the combined effects of dopamine and progesterone receptor activation in the medial amygdala increases the incentive properties of a sexual stimulus. Further study into the interactions of ovarian hormones and mediators of generalized arousal on the processing of sexually-relevant cues informs our understanding of the neurobiology of female sexual motivation and could lead to the development of therapeutics to treat the dysfunctions of sexual desire in women.

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.

Voice in different phases of menstrual cycle among naturally cycling women and users of hormonal contraceptives

Previous studies have shown changes in women's behavior and physical appearance between the non-fertile and fertile phases of the menstrual cycle. It is assumed that these changes are regulated by fluctuations in sex hormone levels across the cycle. Receptors for sex hormones have been found on the vocal folds, suggesting a link between hormone levels and vocal fold function, which might cause changes in voice production. However, attempts to identify changes in voice production across the menstrual cycle have produced mixed results. Therefore, the purpose of this study was to investigate changes in sexually dimorphic vocal characteristics and quality of women's voices in different phases of the cycle and to compare these with users of monophasic hormonal contraception. Voice samples (vowel phonation) of 44 naturally cycling women were obtained in the menstrual, late follicular (confirmed by LH surge) and luteal phases, and in 20 hormonal contraceptive users across equivalent stages of the monthly cycle. Results showed that voices of naturally cycling women had higher minimum pitch in the late follicular phase compared with the other phases. In addition, voice intensity was at its lowest in the luteal phase. In contrast, there were no voice changes across the cycle in hormonal contraceptive users. Comparison between the two groups of women revealed that the naturally cycling group had higher minimum pitch in the fertile phase and higher harmonics to noise ratio in the menstrual phase. In general, present results support the assumption that sex hormones might have an effect on voice function. These results, coupled with mixed findings in previous studies, suggest that vocal changes in relation to hormonal fluctuation are subtle, at least during vowel production. Future studies should explore voice changes in a defined social context and with more free-flowing speech.

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.