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

Estrogen predicts multimodal emotion recognition accuracy across the menstrual cycle

Researchers have proposed that variation in sex hormones across the menstrual cycle modulate the ability to recognize emotions in others. Existing research suggests that accuracy is higher during the follicular phase and ovulation compared to the luteal phase, but findings are inconsistent. Using a repeated measures design with a sample of healthy naturally cycling women (N = 63), we investigated whether emotion recognition accuracy varied between the follicular and luteal phases, and whether accuracy related to levels of estrogen (estradiol) and progesterone. Two tasks assessed recognition of a range of positive and negative emotions via brief video recordings presented in visual, auditory, and multimodal blocks, and non-linguistic vocalizations (e.g., laughter, sobs, and sighs). Multilevel models did not show differences in emotion recognition between cycle phases. However, coefficients for estrogen were significant for both emotion recognition tasks. Higher within-person levels of estrogen predicted lower accuracy, whereas higher between-person estrogen levels predicted greater accuracy. This suggests that in general having higher estrogen levels increases accuracy, but that higher-than-usual estrogen at a given time decreases it. Within-person estrogen further interacted with cycle phase for both tasks and showed a quadratic relationship with accuracy for the multimodal task. In particular, women with higher levels of estrogen were more accurate in the follicular phase and middle of the menstrual cycle. We propose that the differing role of within- and between-person hormone levels could explain some of the inconsistency in previous findings.

Combined perceptual and chemical analyses show no compelling evidence for ovulatory cycle shifts in women's axillary odour

Although men's attraction to women's body odour has been suggested to vary over the ovulatory cycle, peaking around the fertile window, we still lack methodologically robust evidence corroborating this effect. Further, the chemical underpinnings of male preference for the odour of ovulating women remain unknown. Here, we combined perceptual and chemical analyses to investigate the axillary odour of naturally cycling women over 10 days, covering the gradual change in fertility across the ovulatory cycle with a focus on fertile days. The fertile state was confirmed by urinary ovulation tests as well as salivary oestradiol and progesterone levels. Men rated the scent of unfamiliar women, resembling a first encounter. We used multivariate analyses to relate variation in both odour ratings and chemical composition to female conception probability, temporal distance to ovulation and ovarian hormone levels. Our results provide no evidence that males prefer the odour of fertile women. Furthermore, the volatile analysis indicated no link between axillary odour composition and current fertility status. Together, our results showed no convincing support for a chemical fertility cue in women's axillary odour, questioning the presence of olfactory fertility information that is recognizable during first encounters in modern humans.

Ovarian hormones predict cooperative strategies updating during multiple rounds of the prisoner's dilemma

Increasing research has focused on how ovarian hormones influence individual prosocial motivation and cooperation. However, most results remain ambiguous and contradictory. Here, we collected progesterone (PROG) and oestradiol from 62 healthy women with regular menstrual cycles to explore whether variations in ovarian hormones could flexibly change their cooperative preference according to their opponents' strategies in multiple rounds of a prisoner's dilemma (PD) game. Participants in different menstrual phases (32 in the follicular phase [FP] and 30 in the luteal phase [LP]) were asked to complete 20 rounds of PD games with each of three computer opponents holding different cooperative strategies. The results revealed that in PD games that did not require cooperation for increased outcomes, women in the LP (high PROG) reduced their cooperation rate more significantly than women in the FP (low PROG). In contrast, when the game design required reciprocity, simultaneously elevated levels of PROG and oestradiol predicted greater instances of participants choosing to cooperate. Furthermore, we found that elevated PROG levels accounted for women's elevated prosocial choices, regardless of the need to increase outcomes through cooperation. These results implied higher levels of PROG and oestradiol influence women's cooperative strategies resulting in increased social interactions.

Social attention, memory, and memory-guided orienting change across the menstrual cycle

Numerous studies have shown that perception of emotion and emotional memory vary across the menstrual cycle. However, most of these studies used stimuli that contained not only emotional but also social elements. Importantly, the social cognitive abilities of individuals are as crucial as emotional abilities for danger avoidance and recruitment of allies. Therefore, the issue that natural hormonal fluctuations may affect emotion processing should be revisited. To investigate whether the effects of the menstrual cycle are emotion-specific or can also be attributed to social information processing, the present study examined social attention across the menstrual cycle in three tasks-visual search, memory, and memory-guided orienting-with a combination of behavioral and eye-tracking measures. We used images of people standing upright with neutral emotion as social distractors and everyday objects with physical properties matched as non-social distractors. Thirty-six healthy women without hormone use and with stable menstrual cycles of 26 - 30 days participated in the three tasks in the late follicular phase (FP) and mid-luteal phase (LP), respectively. During visual search, participants were asked to search for targets accompanied by social or non-social distractors in complex scenes. Social attentional bias, as evidenced by longer search times and shorter gaze behaviors for targets with social distractors, was found in the FP but not in the LP. In the following memory task, memory accuracy for targets was higher in the FP than in the LP, and the memory for targets with social distractors was more precise in both phases. Finally, in the orienting task, targets in social scenes were detected more slowly than in non-social scenes in LP. Taken together, these findings point to the interplay between social attention, memory, and memory-oriented attention and reveal the distinct processing pathways for social information in the FP and LP. The underlying mechanisms from an evolutionary perspective and from behavioral and neural basis were discussed.

Do women's natural hormonal fluctuations modulate prosociality? A within-subject analysis

Prosocial behavior is central to functional societies. While studies have shown that the administration of exogenous hormones modulates prosocial propensities, it remains unclear whether natural hormonal fluctuations track women's prosocial behavior. In this study, we investigated the relationships between women's natural salivary steroid hormone levels (estradiol, progesterone, and testosterone) and their prosociality in a variety of contexts, as measured by three behavioral tasks (Charitable Donation, Social Value Orientation, and Social Discounting tasks) and one self-reported questionnaire (the Prosocial Tendencies Measure). Participants completed five weekly laboratory tests to obtain within-subject hormonal fluctuation data and prosociality measurements. In a pre-registered analysis, we found little evidence supporting the hypotheses that women's prosociality tracked natural changes in salivary estradiol, progesterone, estradiol-to-progesterone ratio, or testosterone. Our results demonstrate the importance of performing within-subject analyses when examining the relationships between hormonal levels and social behavior.

No Evidence for a Role of Oral Contraceptive-Use in Emotion Recognition But Higher Negativity Bias in Early Follicular Women

Accuracy in facial emotion recognition has shown to vary with ovarian hormones, both in naturally cycling women, as well as in women taking oral contraceptives. It remains uncertain however, if specific – endogenous and exogenous – hormonal levels selectively impact recognition of certain basic emotions (or neutral faces) and if this relationship coincides with certain affective states. Therefore, we investigated 86 women under different hormonal conditions and compared their performance in an emotion recognition task as well as self-reported measures of affective states. Based on self-reported cycle days and ovulation testing, the participants have been split into groups of naturally cycling women during their early follicular phase (fNC, n = 30), naturally cycling women during their peri-ovulatory phase (oNC, n = 26), and women taking oral contraceptives (OC, n = 30). Participants were matched for age and did not differ in education or neuropsychological abilities. Self-reported anxiety and depressive affective state scores were similar across groups, but current affective state turned out to be significantly more negative in fNC women. Independent of negative affective state, fNC women showed a significantly higher negativity bias in recognizing neutral faces, resulting in a lower recognition accuracy of neutral faces compared to oNC and OC women. In the OC group only, negative affective state was associated with lower recognition accuracy and longer response times for neutral faces. Furthermore, there was a significant, positive association between disgust recognition accuracy and negative affective state in the fNC group. Low progesterone levels during the early follicular phase were linked to higher negative affective state, whereas in the peri-ovulatory phase they were linked to elevated positive affective state. Overall, previous findings regarding impaired emotion recognition during OC-use were not confirmed. Synthetic hormones did not show a correlation with emotion recognition performance and affective state. Considering the important role of emotion recognition in social communication, the elevated negativity bias in neutral face recognition found for fNC women may adversely impact social interactions in this hormonal phase.

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.

Friend vs. Foe: Cognitive and Affective Empathy in Women With Different Hormonal States

Empathy is crucial for social functioning as well as social coherence. It can be influenced by modulatory factors such as familiarity and liking (i.e., emotional closeness). Furthermore, there are first hints that hormonal status may modulate affective but not cognitive empathy in women. The aim of this study was to investigate potential separate as well as combined modulatory effects of emotional closeness and hormonal status on female cognitive and affective empathy. Three hormonal status groups of women (n = 62) were studied: (1) naturally-cycling (NC) women in the early follicular phase (fNC), (2) NC women during periovulatory phase (oNC), and (3) oral contraceptive (OC) users. All women underwent a newly developed empathy task (i.e., Tübinger Empathy Test, TET) presenting textual descriptions of positive and negative emotional scenes relating to three different perspectives (i.e., self vs. friend vs. enemy/disliked person). Regardless of hormonal status, empathic responses were higher for the friend compared to the enemy perspective for both empathy components. However, cognitive empathy was less affected by varying emotional closeness toward the target person than affective empathy. Hormonal status modulated only affective empathy. OC users showed significantly less affective empathy toward the enemy compared to the fNC women. Overall, affective empathy seems more sensitive to modulatory effects of emotional closeness and hormonal status than cognitive empathy. Possible implications of this current investigation for future research on empathy and OC use, contraceptive education as well as for other clinical applications are discussed.

No evidence that hormonal contraceptive use or circulating sex steroids predict complex emotion recognition

Relatively little is known about the effects of endogenous and exogenous steroid hormones on ecologically relevant behavioral and cognitive phenotypes in women, such as emotion recognition, despite the widespread use of steroid hormone-altering hormonal contraceptives (HCs). Though some previous studies have examined the effect of HC use, estradiol, progesterone, and testosterone on emotion recognition in women, they have been limited by cross-sectional designs, small sample sizes (total n < 100), and compromised statistical power to detect significant effects. Using data from two test sessions in a large sample of naturally cycling women (NC; n = 192) and women on HCs (n = 203), we found no group differences in emotion recognition; further, the lack of group differences in emotion recognition was not modulated by item difficulty or emotional valence. Among NC women who provided saliva samples across two sessions that were assayed for estradiol and progesterone concentrations, we found no compelling evidence across models that between-subject differences and within-subject fluctuations in these ovarian hormones predicted emotion recognition accuracy, with the exception that between-subjects estradiol negatively predicted emotion recognition for emotions of neutral valence (p = .042). Among HC women who provided saliva samples across two sessions that were assayed for testosterone, we found no compelling evidence that between-subjects differences and within-subject fluctuations in testosterone predicted emotion recognition accuracy. Overall, our analyses provide little support for the idea that circulating endogenous or exogenous ovarian hormones influence emotion recognition in women.

Visual cues to fertility are in the eye (movements) of the beholder

Past work demonstrates that humans behave differently towards women across their menstrual cycles, even after exclusively visual exposure to women's faces. People may look at women's faces differently as a function of women's menstrual cycles. Analyses of participants' scanpaths (eye movement patterns) while they looked at women at different phases of their menstrual cycles revealed that observers exhibit more consistent scanpaths when examining women's faces when women are in a menstrual cycle phase that typically corresponds with peak fertility, whereas they exhibit more variable patterns when looking at women's faces when they are in phases that do not correspond with fertility. A multivariate classifier on participants' scanpaths predicted whether they were looking at the face of a woman in a more typically fertile- versus non-fertile-phase of her menstrual cycle with above-chance accuracy. These findings demonstrate that people look at women's faces differently as a function of women's menstrual cycles, and suggest that people are sensitive to fluctuating visual cues associated with women's menstrual cycle phase.

Interactive effects of ovarian steroid hormones on alcohol use and binge drinking across the menstrual cycle

Patterns and features of substance use and abuse vary across the menstrual cycle in humans. Yet, little work has systematically examined the within-person relationships between ovarian hormone changes and alcohol use across the menstrual cycle. Our study was the first to examine the roles of within-person levels of estradiol (E2) and progesterone (P4) in relation to daily alcohol use and binge drinking in young women. Participants were 22 naturally cycling women, ages 18-22, recruited through a university subject pool who reported any alcohol use and who completed a screening visit assessing study eligibility, followed by 35 subsequent days of data collection. E2 and P4 were obtained via enzyme immunoassay of saliva samples collected by participants each morning, 30 min after waking. Presence and degree of daily substance use were obtained using an adaptation of the Timeline FollowBack Interview completed daily. Results indicated that elevated E2 in the context of decreased P4 levels were associated with higher risk of drinking and binge drinking. These effects were present only on weekend days. Results are suggestive of a dual risk model in which both ovulatory E2 increases and perimenstrual P4 decreases increase risk for drinking. Differential associations of steroids with drinking across the menstrual cycle may suggest the need for clinical assessment of substance use to take into account hormone dynamics and menstrual cycle phase. (PsycINFO Database Record

Menstrual cycle phase predicts women's hormonal responses to sexual stimuli

A robust body of research has demonstrated shifts in women's sexual desire and arousal across the menstrual cycle, with heightened desire and arousal coincident with heightened probability of conception (POC), and it is likely that ovarian hormones modulate these shifts. However, studies in which women are exposed to audiovisual sexual stimuli (AVSS) at high POC (mid-follicular) and low POC (luteal) phases have failed to detect significant differences in genital or subjective arousal patterns based on menstrual cycle phase. Here, we tested whether hormonal responsivity to AVSS differs as a function of cycle phase at testing, and whether phase during which participants were first exposed to AVSS influences hormonal responsivity in subsequent test sessions. Twenty-two naturally cycling heterosexual women were exposed to AVSS during the follicular and luteal phases, with phase at first test session counterbalanced across participants. Salivary samples were collected before and after AVSS exposure. Estradiol increased significantly during both follicular and luteal phase sessions, and increases were higher during the follicular phase. Testosterone (T) increased significantly only during the follicular phase session, while progesterone (P) did not change significantly during either cycle phase. Session order and current cycle phase interacted to predict P and T responses, such that P and T increased during the follicular phase in women who were first tested during the luteal phase. These data suggest that menstrual cycle phase influences hormonal responsivity to AVSS, and contribute to a growing body of clinical and empirical literature on the neuroendocrine modulators of women's sexuality.