Women's luteal-phase sexual proceptivity and the functions of extended sexuality

Ovulatory cycle shifts in human motivational prioritisation of sex and food

Previous research on the endogenous effects of ovarian hormones on motivational states in women has focused on sexual motivation. The Motivational Priority Shifts Hypothesis has a broader scope. It predicts a shift from somatic to reproductive motivation when fertile. In a highly powered preregistered online diary study across 40 days, we tested whether 390 women report such an ovulatory shift in sexual and eating motivation and behaviour. We compared 209 naturally cycling women to 181 women taking hormonal contraceptives (HC) to rule out non-ovulatory changes across the cycle as confounders. We found robust ovulatory decreases in food intake and increases in general sexual desire, in-pair sexual desire and initiation of dyadic sexual behaviour. Extra-pair sexual desire increased mid-cycle, but the effect did not differ significantly in HC women, questioning an ovulatory effect. Descriptively, solitary sexual desire and behaviour, dyadic sexual behaviour, appetite, and satiety showed expected mid-cycle changes that were diminished in HC women, but these failed to reach our strict preregistered significance level. Our results provide insight into current theoretical debates about ovulatory cycle shifts while calling for future research to determine motivational mechanisms behind ovulatory changes in food intake and considering romantic partners' motivational states to explain the occurrence of dyadic sexual behaviour.

Sexual Desire of Women With Fast and Slow Life History Throughout the Ovulatory Cycle

Findings on female sexual motivation across the ovulatory cycle are mixed. Some studies have reported increased female sexual desire on fertile days or midway through the ovulatory cycle, whereas others have reported increased sexual desire on nonfertile days. We postulated and tested the hypothesis that the pattern of the cyclical change of female sexual desire is associated with women's life history. Female participants completed life-history measures and rated their levels of sexual desire on the survey day and reported the first day of their current and subsequent cycle, respectively (Study 1), or recorded their sexual desire throughout an entire cycle by submitting daily reports (Study 2). Results indicate that women with a fast life history experienced peak sexual desire midcycle, whereas women with a slow life history experienced two peaks of sexual desire midcycle and around their menses. These findings suggest that, consistent with the underlying life history, cyclically differential peaking of sexual desire may serve different reproductive functions.

Women's Estrus and Extended Sexuality: Reflections on Empirical Patterns and Fundamental Theoretical Issues

How do women's sexual interests change across their ovulatory cycles? This question is one of the most enduring within the human evolutionary behavioral sciences. Yet definitive, agreed-upon answers remain elusive. One empirical pattern appears to be robust: Women experience greater levels of sexual desire and interest when conceptive during their cycles. But this pattern is not straightforward or self-explanatory. We lay out multiple possible, broad explanations for it. Based on selectionist reasoning, we argue that the conditions that give rise to sexual interests during conceptive and non-conceptive phases are likely to differ. Because conceptive and non-conceptive sex have distinct functions, the sexual interests during conceptive and non-conceptive phases are likely to have different strategic ends. We discuss provisional evidence consistent with this perspective. But the exact nature of women's dual sexuality, if it exists, remains unclear. Additional empirical research is needed. But perhaps more crucially, this topic demands additional theory that fruitfully guides and interprets future empirical research.

Menstrual Cycle Changes in Daily Sexual Motivation and Behavior Among Sexually Diverse Cisgender Women

We used a one-month daily diary assessment to measure menstrual cycle-related changes in same-gender and other-gender sexual motivation and behavior in 148 cisgender women (32% lesbian-identified, 35% bisexually identified, and 33% heterosexual-identified). Women with exclusive same-gender orientations reported increased motivation for same-gender sexual contact during the higher-fertility phase of the cycle, but women with exclusive other-gender orientations did not show a parallel increase in other-gender sexual motivation during the higher-fertility phase. Bisexually attracted women showed no phase-related changes in same-gender or other-gender sexual motivation, regardless of whether they generally preferred one gender versus the other. Rates of partnered sexual contact did not increase during the higher-fertility phase. During the 14 midcycle days during which we assayed salivary estrogen and testosterone, we found no significant associations between daily hormones and sexual motivation. However, daily estrogen levels were positively related to sexual behavior among women currently partnered with women, and negatively related to sexual behavior among women currently partnered with men. Our results suggest that traditional evolutionary models of menstrual cycle-related changes in sexual motivation do not adequately reflect the full range of cycle-related changes observed among sexually diverse women.

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.

Sex-Differentiated Changes in Sexual Desire Predict Marital Dissatisfaction

Sex is critical to marriage. Yet, there are several reasons to expect spouses to experience declines in the desire for sex over time, and the rates of any declines in sexual desire may differ for men and women. We used two multi-wave, longitudinal studies to test whether male and female members of newlywed couples experienced different rates of change in sexual desire, whether any such changes were accentuated by childbirth, and whether any such changes had implications for marital satisfaction. In both studies, spouses provided multiple reports of sexual desire, marital satisfaction, and childbirth. Results demonstrated that women's sexual desire declined more steeply over time than did men's sexual desire, which did not decline on average. Further, childbirth accentuated this sex difference by partially, though not completely, accounting for declines in women's sexual desire but not men's. Finally, declines in women's but not men's sexual desire predicted declines in both partners' marital satisfaction. These effects held controlling depressive symptoms and stress, including stress from parenthood. The current findings offer novel longitudinal evidence for sex-differentiated changes in sexual desire and therefore suggest an important source of marital discord.

How reproductive hormonal changes affect relationship dynamics for women and men: A 15-day diary study

Research suggests that women's sexual psychology and behavior change across the ovulatory cycle, but very little is known about how fluctuations in estradiol and progesterone - two hormones that systematically vary across the ovulatory cycle - affect romantic relationship dynamics. We present the first dyadic study to assess daily hormonal fluctuations and personal and relationship well-being from both partners' perspectives. Specifically, we recruited women who were not using hormonal contraception and their partners for a 15-day diary study. Participants collected daily urine samples to assess estradiol, progesterone, and testosterone, and they responded to daily questions about their relationship. Results revealed that increases in estradiol negatively affected women's relationship evaluations. Men perceived these changes, which in turn, affected men's well-being. The present findings highlight the importance of women's hormonal fluctuations in shaping relationship dynamics and provide, for the first time, information about how such fluctuations affect male partners.

Do women expose themselves to more health-related risks in certain phases of the menstrual cycle? A meta-analytic review

Researchers have increasingly examined the menstrual cycle as a potential source of day-to-day variation in women's cognitions, motivations, and behavior. Within this literature, several lines of research have examined the impact of the menstrual cycle on women's engagement in activities that could negatively affect their health (alcohol and tobacco consumption, sexual behavior, risk recognition). However, findings have been mixed, leaving it unclear whether women may expose themselves to more health-related risks during certain phases of the cycle. We conducted a meta-analysis of 22 published and four unpublished studies (N = 7529, https://osf.io/xr37j/). The meta-analysis revealed shifts across the menstrual cycle in women's sexual behavior with others and risk recognition (higher in ovulatory phase), whereas there was no consistent pattern of difference for alcohol and cigarette consumption. These findings help to clarify the proximate physiological and evolutionary mechanisms underlying women's health-related risk-taking and may inform new interventions.

Hormonal Contraceptives, Female Sexual Dysfunction, and Managing Strategies: A Review

In recent decades, hormonal contraceptives (HC) has made a difference in the control of female fertility, taking an unequivocal role in improving contraceptive efficacy. Some side effects of hormonal treatments have been carefully studied. However, the influence of these drugs on female sexual functioning is not so clear, although variations in the plasma levels of sexual hormones could be associated with sexual dysfunction. Permanent hormonal modifications, during menopause or caused by some endocrine pathologies, could be directly related to sexual dysfunction in some cases but not in all of them. HC use seems to be responsible for a decrease of circulating androgen, estradiol, and progesterone levels, as well as for the inhibition of oxytocin functioning. Hormonal contraceptive use could alter women's pair-bonding behavior, reduce neural response to the expectation of erotic stimuli, and increase sexual jealousy. There are contradictory results from different studies regarding the association between sexual dysfunction and hormonal contraceptives, so it could be firmly said that additional research is needed. When contraceptive-related female sexual dysfunction is suspected, the recommended therapy is the discontinuation of contraceptives with consideration of an alternative method, such as levonorgestrel-releasing intrauterine systems, copper intrauterine contraceptives, etonogestrel implants, the permanent sterilization of either partner (when future fertility is not desired), or a contraceptive ring.

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.

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.

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.

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.

Hormonal systems, human social bonding, and affiliation

Which hormones are implicated in human social bonding and affiliation? And how does field research speak to this issue? We begin by laying out a broad view of how endocrine hormones in general modulate life history allocations of energy and other resources, and the ways in which their neuromodulatory functions must be understood within a broader conceptualization of how they have been shaped to affect allocations. We then turn to four specific hormones or hormone families that have received much attention: oxytocin, opioids, prolactin, and progesterone. Each plays a role in regulating psychological capacities and propensities that underlie individuals' interactions with important social targets. Yet in no case is it clear exactly what regulatory roles these hormones play. We suggest several directions for future research.

Oxytocin and vulnerable romantic relationships

Oxytocin (OT) has been implicated in the formation and maintenance of various social relationships, including human romantic relationships. Competing models predict, alternatively, positive or negative associations between naturally-occurring OT levels and romantic relationship quality. Empirical tests of these models have been equivocal. We propose a novel hypothesis ('Identify and Invest') that frames OT as an allocator of psychological investment toward valued, vulnerable relationships, and test this proposal in two studies. In one sample of 75 couples, and a second sample of 148 romantically involved individuals, we assess facets of relationships predicting changes in OT across a thought-writing task regarding one's partner. In both studies, participants' OT change across the task corresponded positively with multiple dimensions of high relationship involvement. However, increases in participants' OT also corresponded to their partners reporting lower relationship involvement. OT increases, then, reflected discrepancies between assessments of self and partner relationship involvement. These findings are robust in a combined analysis of both studies, and do not significantly differ between samples. Collectively, our findings support the 'Identify and Invest' hypothesis in romantic couples, and we argue for its relevance across other types of social bonds.

Monogamy and Nonmonogamy: Evolutionary Considerations and Treatment Challenges

INTRODUCTION

Few topics generate such controversy and emotional reactivity as the nature of human mating behavior. Unfortunately, and potentially to the detriment of good patient care, sexual medicine practitioners have largely avoided this matter. An understanding of the scientific literature can empower practitioners to more effectively confront the inevitable monogamy and nonmonogamy challenges present in research and clinical practice.

AIM

To review and summarize relevant scientific literature as a context to evaluate the more common myths and misunderstanding relating to the practice of monogamy and nonmonogamy in humans. This review also is intended to promote a discussion of the ways human mating strategies may impact sexual function and dysfunction for the individual and couple.

METHODS

A review of English written peer-reviewed evolutionary, anthropological, neuropsychiatric, zoological research, and other scholarly texts was conducted. Work published between 2000 and 2016 concentrating on evolutionary theory, long- and short-term mating strategies in primates and most specifically in humans, and consensual nonmonogamy was highlighted.

MAIN OUTCOME MEASURES

Main outcomes included a brief explanation of evolutionary theory and a review of relevant literature regarding long- and short-term mating behaviors and consensual nonmonogamy.

RESULTS

Serial sexual and social monogamy is the norm for humans. Across time and cultures, humans have adapted both long- and short-term mating strategies that are used flexibly, and sometimes simultaneously, based on unique personal, social, and environmental circumstances.

CONCLUSION

Human mating behavior is individualistic, the result of numerous biopsychosocial influences. The clinician cannot assume that an individual presenting as a patient maintains a monogamy-valued view of his or her intimate relationship. Patients may experience conflict between the cultural monogamous ideal and their actual sexual behaviors. This conflict may be critical in understanding a patient's sexual concerns and in treatment planning. Awareness of these issues will aid the practitioner in sexual medicine.

Within-cycle fluctuations in progesterone negatively predict changes in both in-pair and extra-pair desire among partnered women

Grebe et al. (2016) argued that women's sexual interest in their own partners may be under different hormonal regulation than their sexual desire for other men. They measured partnered women's salivary hormones and reports of attraction to different categories of men at two time points separated by one week. Change in progesterone positively predicted change in women's desire for their own partners, whereas change in estradiol was a negative predictor. These results are opposite to those we previously reported for the hormonal prediction of general sexual desire in a study that employed frequent hormone sampling across multiple menstrual cycles (Roney and Simmons, 2013). Here, to test replication of the Grebe et al. findings, we assessed hormonal predictors of targeted in-pair and extra-pair desire among the subset of the sample from our 2013 paper who reported being in romantic relationships. Contrary to Grebe et al. (2016), we found that within-cycle fluctuations in progesterone were negatively correlated with changes in women's desire for both their own partners and other men. In addition, both in-pair and extra-pair desire were elevated within the fertile window and lowest during the luteal phase. Our findings contradict the idea that partner-specific desire has a unique form of hormonal regulation, and instead support a general elevation of sexual motivation associated with hormonal indices of fecundity. Discussion focuses on possible reasons for the discrepancies in findings between our study and that of Grebe et al. (2016), and on the evolved functions of women's sexual motivation.

Capturing the Interpersonal Implications of Evolved Preferences? Frequency of Sex Shapes Automatic, but Not Explicit, Partner Evaluations

A strong predisposition to engage in sexual intercourse likely evolved in humans because sex is crucial to reproduction. Given that meeting interpersonal preferences tends to promote positive relationship evaluations, sex within a relationship should be positively associated with relationship satisfaction. Nevertheless, prior research has been inconclusive in demonstrating such a link, with longitudinal and experimental studies showing no association between sexual frequency and relationship satisfaction. Crucially, though, all prior research has utilized explicit reports of satisfaction, which reflect deliberative processes that may override the more automatic implications of phylogenetically older evolved preferences. Accordingly, capturing the implications of sexual frequency for relationship evaluations may require implicit measurements that bypass deliberative reasoning. Consistent with this idea, one cross-sectional and one 3-year study of newlywed couples revealed a positive association between sexual frequency and automatic partner evaluations but not explicit satisfaction. These findings highlight the importance of automatic measurements to understanding interpersonal relationships.

Hormonal predictors of women's extra-pair vs. in-pair sexual attraction in natural cycles: Implications for extended sexuality

In naturally cycling women, Roney and Simmons (2013) examined hormonal correlates of their desire for sexual contact. Estradiol was positively associated, and progesterone negatively associated, with self-reported desire. The current study extended these findings by examining, within a sample of 33 naturally cycling women involved in romantic relationships, hormonal correlates of sexual attraction to or interests in specific targets: women's own primary partner or men other than women's primary partner. Women's sexual interests and hormone (estradiol, progesterone, and testosterone) levels were assessed at two different time points. Whereas estradiol levels were associated with relatively greater extra-pair sexual interests than in-pair sexual interests, progesterone levels were associated with relatively greater in-pair sexual interests. Both hormones specifically predicted in-pair sexual desire, estradiol negatively and progesterone positively. These findings have implications for understanding the function of women's extended sexuality - their sexual proceptivity and receptivity outside the fertile phase, especially during the luteal phase.

Factors predicting the probability of initiating sexual intercourse by context and sex

Despite men initiating sex more than women there is considerable variance within the sexes. This study is the first to consider the impact of multiple predictors from the literature, and investigates how factors, such as relationship length, sociosexuality, and different aspects of self-perceived mate value among others, independently and interactively predict initiation of sexual intercourse in both short-term sexual and long-term romantic mating contexts, testing predictions from Sexual strategies theory. For long-term relationships, positive partner bond increased initiative to sexual intercourse for women. For men, self-perceived independence increased probability of taking the initiative, while relationship attachment decreased probability. For short-term relations, the desire component of the sociosexual orientation inventory increased probability of initiation for both sexes, while male initiative was increased by pleasure reasons for sex. The impact of individual predictors on initiating intercourse is influenced by being included in a multidimensional model, and relationship context affects the impact of the predictors.

Women ornament themselves for intrasexual competition near ovulation, but for intersexual attraction in luteal phase

The present study examined women's attentional bias toward ornamental objects in relation to their menstrual phase as well as to motivations of intersexual courtship or intrasexual competition. In Experiment 1, 33 healthy heterosexual women were tested in a bias-assessment visual cuing task twice: once on a high-fertility day (during the ovulatory phase) and once on a low-fertility day (during the luteal phase). They paid greater attention to pictures of ornamental objects than to pictures of non-ornamental objects near ovulation, but not during the luteal phase, suggesting an ornamental bias during the high-fertility phase. In Experiment 2, before the visual cuing task, 40 participants viewed 10 same-sex or opposite-sex facial photographs with either high or low attractiveness as priming tasks to activate the intrasexual competition or intersexual courtship motives. Results showed that women's ornamental bias was dependent on the interaction of menstrual phase and mating motive. Specifically, the ornamental bias was observed on the high-fertility day when the subjects were primed with high-attractive same-sex images (intrasexual competition) and was observed on the low-fertility day when they were primed with high-attractive opposite-sex photographs (intersexual courtship). In conclusion, the present findings confirm the hypothesis that, during the high-fertility phase, women have an attentional bias toward ornamental objects and further support the hypothesis that the ornamental bias is driven by intrasexual competition motivation near ovulation, but driven by intersexual courtship motivation during the luteal phase.