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.

Variables emocionales y food craving: influencia del ciclo menstrual / Emotional variables and food craving: influence of the menstrual cycle

Antecedentes: El ciclo reproductor femenino - que implica interacciones entre el cerebro, el útero y los ovarios - está constituido por la fase folicular o proliferativa (también denominada pre-ovulatoria), posteriormente, tiene lugar la ovulación, tras ella comienza la fase lútea o secretora y, por último, tiene lugar la fase menstrual. Durante el ciclo menstrual la mujer experimenta cambios hormonales que pueden provocarle síntomas físicos, psicológicos y comportamentales como cambios en el apetito, pudiendo afectarle así a su ingesta alimentaria. Un fenómeno observado durante la menstruación es el food craving, definido como una necesidad irresistible de consumir comida (“ansia”), siendo predominante desear consumir alimentos procesados durante la fase premenstrual, conducta que, también se asocia a un estado de ánimo negativo. No obstante, numerosos y diversos patrones alimentarios, así como también fluctuaciones en el estado emocional, se han observado en la mujer durante las diversas fases del ciclo menstrual. Por ello, es necesario una mayor investigación en esta área. Objetivos y método: El presente trabajo, tiene como objetivos observar la variación del food craving en función de las diferentes fases del ciclo menstrual y observar la influencia de variables emocionales (ansiedad-estado de ánimo negativo) en el “ansia por comer” (food craving). Para ello, se ha realizado una búsqueda bibliográfica en las bases de datos PubMed, Scopus y otras fuentes como Wiley Online Library y ResearchGate, para obtener y contrastar las ideas de los autores de estudios previos con respecto al tema.(AU)

Background: The female reproductive cycle which involves interactions between the brain, the uterus and the ovaries, is made up of the follicular or proliferative phase (also called pre-ovulatory), later, ovulation takes place, after which the luteal or secretory phase begins and, finally, the menstrual phase takes place. During the menstrual cycle, the woman experiences hormonal changes that can cause physical, psychological and behavioral symptoms such as changes in appetite, thus affecting her food intake. A phenomenon observed during menstruation is food craving, defined as an irresistible need to consume food ("craving"), predominantly wanting to consume processed foods during the premenstrual phase, a behavior that, is also associated with a negative mood. However, numerous and diverse eating patterns, as well as fluctuations in emotional state, have been observed in women during the various phases of the menstrual cycle. Therefore, further research is needed in this area. Objectives and method: The present work aims to observe the variation of food craving in function of the different phases of the menstrual cycle and to observe the influence of emotional variables (anxiety-negative mood) in the “craving to eat” (food craving). For this, a bibliographic search was carried out in the databases PubMed, Scopus and other sources such as Wiley Online Library and ResearchGate, to obtain and contrast the ideas of the authors of previous studies regarding the topic. Discussion: It has been observed that there is a tendency to a higher energy-food pattern during the luteal phase together with an experience “food craving” also increased during this stage, in comparison with other phases of the menstrual cycle.(AU)

Male brain processing of the body odor of ovulating women compared to that of pregnant women.

Female chemical signals underlie the advertising of sexual receptivity and fertility. Whether the body odor of a pregnant woman also has a signaling function with respect to male behavior is yet to be conclusively established. This study examines how the body odors of ovulating and pregnant women differentially affect the behavior of heterosexual men. Body odor samples were collected from 5 pregnant women and 5 matched controls during ovulation. In a double-blind functional magnetic resonance imaging design, 18 heterosexual men were exposed to female body odors during ovulation (OV) and pregnancy (PRG) while being required to indicate the attractiveness of concurrently presented female portrait images. The participants were also required to indicate whether they assumed a depicted woman was pregnant. While neither OV nor PRG altered the perceived attractiveness of a presented face, the men tended to identify the women as pregnant while exposed to a PRG body odor. On the neural level, OV activated a network of the frontotemporal and limbic regions, while PRG activated the superior medial frontal gyrus. The results suggest that the detection of sexual availability activates the male brain regions associated with face processing and reward/motivation, whereas sensing pregnancy activates a region responsible for empathy and prosocial behavior. Thus, the female body odor during pregnancy likely helps foster circumstances conducive to the future care of offspring while the body odor advertising sexual availability promotes mating behavior. The brains of heterosexual men may be capable of unconsciously discriminating between these two types of olfactory stimuli.

Self-Deception about Fecundity in Women : Modeling the Burley Hypothesis.

Concealed fecundity and extended female sexual receptivity have evolved in some primates, including humans, conferring advantages both within primarily monogamous relationships (e.g., benefits from paternity assurance) and from extrapair liaisons (e.g., better access to good genes). As humans evolved the intellectual capacity for decision-making, women became capable of altering their own fertility. In some circumstances, they may choose to ameliorate risks and responsibilities associated with pregnancy by reducing sexual motivation near the perceived most fecund time of their menstrual cycle. But three findings-a general inability of women to accurately recognize their own intervals of fecundity, high variability in ovulation timing, and unconscious transmission and reception of cues associated with fecundity-constitute a physiological and behavioral syndrome that can be considered self-deception. In this study, I develop a descriptive model to determine implications of the hypothesis that these features of female and male physiology and behavior have been shaped by natural selection in response to female decision-making. My analysis shows that consensus motivation for coitus between partners influences both the importance of variable ovulation date and the probability of conception, under the influence of self-deception. It also identifies priorities for future empirical work.

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.

Do women's preferences for masculine voices shift across the ovulatory cycle?

Are estrous mate preference shifts robust? This question is the subject of controversy within human evolutionary sciences. For nearly two decades, mate preference shifts across the ovulatory cycle were considered an important feature of human sexual selection, directing women's attention toward mates with indicators of "good genes" in their fertile phase, when conception is possible. However, several recent studies on masculine faces, bodies and behaviors did not find evidence supporting this account, known as the good genes ovulatory shift hypothesis. Furthermore, evidence that preferences for masculine characteristics in men's voices are related to women's cycle phase and hormonal status is still equivocal. Here, we report two independent within-subject studies from different labs with large sample sizes (N = 202 tested twice in Study 1; N = 157 tested four times in Study 2) investigating cycle shifts in women's preferences for masculine voices. In both studies, hormonal status was assessed directly using salivary assays of steroid hormones. We did not find evidence for effects of cycle phase, conception risk, or steroid hormone levels on women's preferences for masculine voices. Rather, our studies partially provide evidence for cycle shifts in women's general attraction to men's voices regardless of masculine characteristics. Women's relationship status and self-reported stress did not moderate these findings, and the hormonal pattern that influences these shifts remains somewhat unclear. We consider how future work can clarify the mechanisms underlying psychological changes across the ovulatory cycle.

The Woman in Red: Examining the Effect of Ovulatory Cycle on Women's Perceptions of and Behaviors Toward Other Women.

Previous research has shown that during her monthly peak fertile window, a woman competes with other women for a suitable mate. Drawing upon research on ovulation and socially constructed meanings of the color red, we examine how a woman's fertility status and red clothing worn by a target woman change perceptions of the target, as well as behaviors toward the target. Following previous research on the ovulatory status and color red effects, we rely on both hormonal and self-reported fertility data. Across six studies, our research fails to provide support for the prediction that an ovulating woman is less likely to trust another woman wearing red compared with a nonovulating woman.

Effects of stress on women's preference for male facial masculinity and their endocrine correlates.

Women's preferences for masculinity in men's faces seem to vary across the menstrual cycle and are assumed to be strongest around ovulation. A number of hormones have been proposed to underlie these subtle cyclic shifts. Furthermore, mating preferences are context-dependent, and stress has been found to alter mate choice, both in animals and humans. Currently, the effects of stress on women's preference for masculinity remain unknown. To examine the hormonal basis and the impact of stress on facial masculinity preference, we tested for within-subject changes in 52 healthy young women who underwent the Trier Social Stress Test (TSST) and the placebo-TSST in randomized order in the late follicular and mid-luteal phases of their menstrual cycle. Menstrual cycle phase and hormone levels were confirmed using estradiol, testosterone, progesterone, and cortisol analyses from saliva. Results show that women were more likely to be attracted to masculine-faced men right before ovulation than in the mid-luteal phase. Estradiol modulated this masculinity preference with high estradiol levels being related to stronger masculinity preference. When stressed however, women experienced a decrease in male facial masculinity preference. In line with these findings, the higher the cortisol increase to stress, the less were masculine faces preferred to more feminine faces. Mate choice is a central component of reproduction. The present results provide information about the effects of stress and hormonal influences on mate preferences in women.

Can women detect cues to ovulation in other women's faces?

Recent research suggests that men find portraits of ovulatory women more attractive than photographs of the same women taken during the luteal phase. Only few studies have investigated whether the same is true for women. The ovulatory phase matters to men because women around ovulation are most likely to conceive, and might matter to women because fertile women might pose a reproductive threat. In an online study 160 women were shown face pairs, one of which was assimilated to the shape of a late follicular prototype and the other to a luteal prototype, and were asked to indicate which face they found more attractive. A further 60 women were tested in the laboratory using a similar procedure. In addition to choosing the more attractive face, these participants were asked which woman would be more likely to steal their own date. Because gonadal hormones influence competitive behaviour, we also examined whether oestradiol, testosterone and progesterone levels predict women's choices. The women found neither the late follicular nor the luteal version more attractive. However, naturally cycling women with higher oestradiol levels were more likely to choose the ovulatory woman as the one who would entice their date than women with lower oestradiol levels. These results imply a role of oestradiol when evaluating other women who are competing for reproduction.

Women selectively guard their (desirable) mates from ovulating women.

For women, forming close, cooperative relationships with other women at once poses important opportunities and possible threats-including to mate retention. To maximize the benefits and minimize the costs of same-sex social relationships, we propose that women's mate guarding is functionally flexible and that women are sensitive to both interpersonal and contextual cues indicating whether other women might be likely and effective mate poachers. Here, we assess one such cue: other women's fertility. Because ovulating (i.e., high-fertility) women are both more attractive to men and also more attracted to (desirable) men, ovulating women may be perceived to pose heightened threats to other women's romantic relationships. Across 4 experiments, partnered women were exposed to photographs of other women taken during either their ovulatory or nonovulatory menstrual-cycle phases, and consistently reported intentions to socially avoid ovulating (but not nonovulating) women-but only when their own partners were highly desirable. Exposure to ovulating women also increased women's sexual desires for their (highly desirable) partners. These findings suggest that women can be sensitive to subtle cues of other women's fertility and respond (e.g., via social exclusion, enhanced sexual attention to own mate) in ways that may facilitate their mate retention goals while not thwarting their affiliative goals.

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.

Menstrual cycle phase affects discrimination of infant cuteness.

Recent studies have shown that women are more sensitive than men to subtle cuteness differences in infant faces. It has been suggested that raised levels in estradiol and progesterone may be responsible for this advantage. We compared young women's sensitivity to computer-manipulated baby faces varying in cuteness. Thirty-six women were tested once during ovulation and once during the luteal phase of their menstrual cycle. In a two alternative forced-choice experiment, participants chose the baby which they thought was cuter (Task 1), younger (Task 2), or the baby that they would prefer to babysit (Task 3). Saliva samples to assess levels of estradiol, progesterone and testosterone were collected at each test session. During ovulation, women were more likely to choose the cuter baby than during the luteal phase, in all three tasks. These results suggest that cuteness discrimination may be driven by cyclic hormonal shifts. However none of the measured hormones were related to increased cuteness sensitivity. We speculate that other hormones than the ones measured here might be responsible for the increased sensitivity to subtle cuteness differences during ovulation.

The self-regulation effect of fertility status on inbreeding aversion: when fertile, disgust increases more in response to descriptions of one's own than of others' inbreeding.

The ovulatory shift modulates emotions related to female sexuality. Because fertility status only affects the individual's own opportunity cost, the adaptive value of this shift is expected to stem from self-regulation. To test this assumption we asked women to contemplate various inbreeding descriptions: 1) they themselves having sex with male relatives; 2) their sister having sex with their common male relatives; and 3) an unrelated woman having sex with her male relatives (in 1, but not 2 and 3, negative fitness consequences are affected by the participant's fertility). We dichotomized the dependent variable disgust (ceiling vs. non-ceiling) and analyzed the interaction between fertility status and description type. The ovulatory shift was stronger in descriptions where they themselves were described as engaging in inbreeding. A smaller increase was also found in reactions to others engaging in inbreeding. We explain the latter effect as due to self-reflection.

Elastic analysis procedures: an incurable (but preventable) problem in the fertility effect literature. Comment on Gildersleeve, Haselton, and Fales (2014).

Gildersleeve, Haselton, and Fales (2014) presented a meta-analysis of the effects of fertility on mate preferences in women. Research in this area has categorized fertility using a great variety of methods, chiefly based on self-reported cycle length and time since last menses. We argue that this literature is particularly prone to hidden experimenter degrees of freedom. Studies vary greatly in the duration and timing of windows used to define fertile versus nonfertile phases, criteria for excluding subjects, and the choice of what moderator variables to include, as well as other variables. These issues raise the concern that many or perhaps all results may have been created by exploitation of unacknowledged degrees of freedom ("p-hacking"). Gildersleeve et al. sought to dismiss such concerns, but we contend that their arguments rest upon statistical and logical errors. The possibility that positive results in this literature may have been created, or at least greatly amplified, by p-hacking receives additional support from the fact that recent attempts at exact replication of fertility results have mostly failed. Our concerns are also supported by findings of another recent review of the literature (Wood, Kressel, Joshi, & Louie, 2014). We conclude on a positive note, arguing that if fertility-effect researchers take advantage of the rapidly emerging opportunities for study preregistration, the validity of this literature can be rapidly clarified.

Elusiveness of menstrual cycle effects on mate preferences: comment on Gildersleeve, Haselton, and Fales (2014).

This comment uses meta-analytic techniques to reconcile the apparent conflict between Gildersleeve, Haselton, and Fales's (2014) conclusion of "robust" effects of menstrual cycles on women's preferences for men of purported genetic quality and Wood, Kressel, Joshi, and Louie's (2014) assessment that the few, limited effects in this literature appear to be research artifacts. Despite these divergent conclusions, the literature in both reviews shows a broad distribution of effects, with fully one third of findings countering evolutionary psychology predictions. We demonstrate that Gildersleeve et al.'s conclusions were influenced by a small minority of supportive studies. Furthermore, we show that in both reviews, these supportive studies used imprecise estimates of women's cycle phase by failing to validate cycle day (e.g., with hormonal tests) or by including a large number of days in the fertile phase. More recently, as published studies have used more precise methods to estimate menstrual phase, the effect has declined to zero. Additionally, publication status proved important in both reviews, with published but not unpublished studies showing the predicted effects. In general, the limited evidence for evolutionary psychology predictions calls for more sophisticated models of hormonal processes in human mating.

Meta-analyses and p-curves support robust cycle shifts in women's mate preferences: reply to Wood and Carden (2014) and Harris, Pashler, and Mickes (2014).

Two meta-analyses evaluated shifts across the ovulatory cycle in women's mate preferences but reported very different findings. In this journal, we reported robust evidence for the pattern of cycle shifts predicted by the ovulatory shift hypothesis (Gildersleeve, Haselton, & Fales, 2014). However, Wood, Kressel, Joshi, and Louie (2014) claimed an absence of compelling support for this hypothesis and asserted that the few significant cycle shifts they observed were false positives resulting from publication bias, p-hacking, or other research artifacts. How could 2 meta-analyses of the same literature reach such different conclusions? We reanalyzed the data compiled by Wood et al. These analyses revealed problems in Wood et al.'s meta-analysis-some of which are reproduced in Wood and Carden's (2014) comment in the current issue of this journal-that led them to overlook clear evidence for the ovulatory shift hypothesis in their own set of effects. In addition, we present right-skewed p-curves that directly contradict speculations by Wood et al.; Wood and Carden; and Harris, Pashler, and Mickes (2014) that supportive findings in the cycle shift literature are false positives. Therefore, evidence from both of the meta-analyses and the p-curves strongly supports genuine, robust effects consistent with the ovulatory shift hypothesis and contradicts claims that these effects merely reflect publication bias, p-hacking, or other research artifacts. Unfounded speculations about p-hacking distort the research record and risk unfairly damaging researchers' reputations; they should therefore be made only on the basis of firm evidence.

Is preference for ovulatory female's faces associated with men's testosterone levels?

Women's ovulation is perceivable with different senses. Already subtle face shape differences are enough to trigger men's preference for the ovulatory female. The aim of the present study is to investigate if men's testosterone level can be linked to their preference for the ovulatory female. Thirty-nine heterosexual participants were shown face pairs of which one of them was transformed to the shape of a prototype face of a woman in her luteal cycle phase and the other was transformed to the shape of a prototype face of an ovulatory woman. Participants were asked to choose the face which they perceived as being more attractive (attractiveness task), or the woman with whom they would have better chances to get a date (dating task). In both tasks, the ovulatory female was chosen more often. Testosterone was not predictive for the chosen face; regardless of testosterone level men preferred the ovulatory woman. However testosterone predicted how confident the men were with their choice. Men with lower testosterone levels were more confident with their choice than men with higher testosterone levels.

The impact of weather on women's tendency to wear red or pink when at high risk for conception.

Women are particularly motivated to enhance their sexual attractiveness during their most fertile period, and men perceive shades of red, when associated with women, as sexually attractive. Building on this research, we recently found that women are more likely to wear reddish clothing when at peak fertility (Beall & Tracy, 2013), presumably as a way of increasing their attractiveness. Here, we first report results from a methodological replication, conducted during warmer weather, which produced a null effect. Investigating this discrepancy, we considered the impact of a potentially relevant contextual difference between previous research and the replication: current weather. If the red-dress effect is driven by a desire to increase one's sexual appeal, then it should emerge most reliably when peak-fertility women have few alternative options for accomplishing this goal (e.g., wearing minimal clothing). Results from re-analyses of our previously collected data and a new experiment support this account, by demonstrating that the link between fertility and red/pink dress emerges robustly in cold, but not warm, weather. Together, these findings suggest that the previously documented red-dress effect is moderated by current climate concerns, and provide further evidence that under certain circumstances red/pink dress is reliably associated with female fertility.

Do women's mate preferences change across the ovulatory cycle? A meta-analytic review.

Scientific interest in whether women experience changes across the ovulatory cycle in mating-related motivations, preferences, cognitions, and behaviors has surged in the past 2 decades. A prominent hypothesis in this area, the ovulatory shift hypothesis, posits that women experience elevated immediate sexual attraction on high- relative to low-fertility days of the cycle to men with characteristics that reflected genetic quality ancestrally. Dozens of published studies have aimed to test this hypothesis, with some reporting null effects. We conducted a meta-analysis to quantitatively evaluate support for the pattern of cycle shifts predicted by the ovulatory shift hypothesis in a total sample of 134 effects from 38 published and 12 unpublished studies. Consistent with the hypothesis, analyses revealed robust cycle shifts that were specific to women's preferences for hypothesized cues of (ancestral) genetic quality (96 effects in 50 studies). Cycle shifts were present when women evaluated men's "short-term" attractiveness and absent when women evaluated men's "long-term" attractiveness. More focused analyses identified specific characteristics for which cycle shifts were or were not robust and revealed areas in need of more research. Finally, we used several methods to assess potential bias due to an underrepresentation of small effects in the meta-analysis sample or to "researcher degrees of freedom" in definitions of high- and low-fertility cycle phases. Neither type of bias appeared to account for the observed cycle shifts. The existence of robust relationship context-dependent cycle shifts in women's mate preferences has implications for understanding the role of evolved psychological mechanisms and the ovulatory cycle in women's attractions and social behavior.

Fertile and selectively flirty: women's behavior toward men changes across the ovulatory cycle.

Past research shows that men respond to women differently depending on where women are in their ovulatory cycle. But what leads men to treat ovulating women differently? We propose that the ovulatory cycle alters women's flirting behavior. We tested this hypothesis in an experiment in which women interacted with different types of men at different points in their cycle. Results revealed that women in the ovulatory phase reported more interest in men who had purported markers of genetic fitness as short-term mates, but not as long-term mates. Furthermore, behavioral ratings of the interactions indicated that women displayed more flirting behaviors when they were at high than at low fertility. Importantly, fertile women flirted more only when interacting with men who had genetic-fitness markers, not with other men. In summary, fertility not only alters women's behavior but does so in a context-dependent way that follows adaptive logic.