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.

Ovarian hormones in relation to naturally cycling women's conception risk: Empirical evidence and implications for behavioral endocrinology.

A substantial body of literature has examined how women's psychology and behavior vary as a function of conception risk across the ovarian cycle. These effects are widely believed to be outcomes of hormonal regulation, in particular effects of estrogens (E) and progesterone (P). Increasingly, researchers have sought to test predictions about how psychological processes or behavior vary as a function of conception risk by examining associations with estrogen (e.g., estradiol) and progesterone levels. Yet issues regarding how best to assess these associations arise. Should hormone levels be log-transformed? Do hormone ratios best capture their joint effects? How important are hormone interactions? How should outliers be treated? Across two large datasets, we examined hormonal predictors of conception risk, estimated from day of a luteinizing hormone (LH) surge. Log-transformed E and P levels predicted conception risk better than raw E and P levels did. The raw E/P ratio was a relatively poor predictor, whereas the log-transformed ratio (ln[E/P]) was a relatively good predictor. E × P interactions were detected but weak. Outliers were frequent, especially in distributions of raw hormone levels. Hormone measures predicted two psychological outcomes in these datasets-sexual desire and preferences for strength and muscularity-in parallel to how strongly they predicted conception risk. These results give rise to several recommendations regarding treatment of hormone measures and their use in analyses.

Endocrinological effects of social exclusion and inclusion: Experimental evidence for adaptive regulation of female fecundity.

When current conditions are probabilistically less suitable for successful reproduction than future conditions, females may prevent or delay reproduction until conditions improve. Throughout human evolution, social support was likely crucial to female reproductive success. Women may thus have evolved fertility regulation systems sensitive to cues from the social environment. However, current understanding of how psychological phenomena might affect female ovarian function is limited. In this study, we examined whether cues of reduced social support-social ostracism-impact women's hormone production. Following an in-lab group bonding task, women were randomly assigned to a social exclusion (n = 88) or social inclusion (n = 81) condition. After social exclusion, women with low background levels of social support experienced a decrease in estradiol relative to progesterone. In contrast, socially-included women with low background social support experienced an increase in estradiol relative to progesterone. Hormonal changes in both conditions occurred specifically when women were in their mid-to-late follicular phase, when baseline estradiol is high and progesterone is low. Follow-up analyses revealed that these changes were primarily driven by changes in progesterone, consistent with existing evidence for disruption of ovarian function following adrenal release of follicular-phase progesterone. Results offer support for a potential mechanism by which fecundity could respond adaptively to the loss or lack of social support.

Testosterone, cortisol, and status-striving personality features: A review and empirical evaluation of the Dual Hormone hypothesis.

Decades of research in behavioral endocrinology has implicated the gonadal hormone testosterone in the regulation of mating effort, often expressed in primates in the form of aggressive and/or status-striving behavior. Based on the idea that neuroendocrine axes influence each other, recent work among humans has proposed that links between testosterone and indices of status-striving are rendered conditional by the effects of glucocorticoids. The Dual Hormone hypothesis is one particular instance of this argument, predicting that cortisol blocks the effects of testosterone on dominance, aggression, and risk-taking in humans. Support for the Dual Hormone hypothesis is wide-ranging, but considerations of theoretical ambiguity, null findings, and low statistical power pose problems for interpreting the published literature. Here, we contribute to the development of the Dual Hormone hypothesis by (1) critically reviewing the extant literature-including p-curve analyses of published findings; and, (2) "opening the file drawer" and examining relationships between testosterone, cortisol, and status-striving personality features in seven previously published studies from our laboratories (total N = 718; median N per feature = 318) that examined unrelated predictions. Results from p-curve suggest that published studies have only 16% power to detect effects, while our own data show no robust interactions between testosterone and cortisol in predicting status-striving personality features. We discuss the implications of these results for the Dual Hormone hypothesis, limitations of our analyses, and the development of future research.

Rethinking IL-6 and CRP: Why they are more than inflammatory biomarkers, and why it matters.

Behavioral researchers have increasingly become interested in the idea that chronic, low-grade inflammation is a pathway through which social and behavioral variables exert long-term effects on health. Much research in the area employs putative inflammatory biomarkers to infer an underlying state of inflammation. Interleukin 6 (IL-6) and C-reactive protein (CRP, whose production is stimulated by IL-6) are arguably the two most commonly assayed biomarkers. Yet, in contrast with near-universal assumptions in the field, discoveries in immunology over the past two decades show that neither IL-6 nor CRP are unambiguous inflammatory markers. IL-6 operates through two distinct signaling pathways, only one of which is specifically upregulated during inflammation; both pathways have a complex range of effects and influence multiple physiological processes even in absence of inflammation. Similarly, CRP has two isoforms, one of which is produced locally in inflamed or damaged tissues. The other isoform is routinely produced in absence of inflammation and may have net anti-inflammatory effects. We propose a functional framework to account for the multiple actions of IL-6 and CRP. Specifically, we argue that both molecules participate in somatic maintenance efforts; hence elevated levels indicate that an organism is investing in protection, preservation, and/or repair of somatic tissue. Depending on the state of the organism, maintenance may be channeled into resistance against pathogens (including inflammation), pathogen tolerance and harm reduction, or tissue repair. The findings and framework we present have a range of potential implications for the interpretation of empirical findings in this area-a point we illustrate with alternative interpretations of research on socioeconomic status, stress, and depression.

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.

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.

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

Women's sexuality, unlike that of most mammals, is not solely defined by sexual receptivity during the short window of fertility. Women demonstrate extended sexuality (in which they initiate and accept sexual advances outside of the fertile phase) more than any other mammalian female. In this light, surprisingly little research has addressed the functions of women's luteal-phase sexuality. On the basis of theory and comparative evidence, we propose that women's initiation of sex during nonfertile phases evolved in part to garner investment from male partners. If so, women should be particularly prone to initiate luteal-phase sex when the potential marginal gains are greatest. Results from a study of 50 heterosexual couples showed that women increasingly initiate sex in the luteal phase (but not the fertile phase) when they perceive their partners' investment to lag behind their own. These findings provide evidence for the distinct nature of women's extended sexuality and may contribute to a more comprehensive understanding of women's sexuality.

Developmental instability, fluctuating asymmetry, and human psychological science.

Developmental instability (DI) is an individual's inability to produce a specific developmental outcome under a given set of conditions, generally thought to result from random perturbations experienced during development. Fluctuating asymmetry (FA) - asymmetry on bilateral features that, on average, are symmetrical (or asymmetry deviating from that arising from design) - has been used to measure DI. Dating to half a century ago, and accelerating in the past three decades, psychological researchers have examined associations between FA (typically measured on bodily or facial features) and a host of outcomes of interest, including psychological disorders, cognitive ability, attractiveness, and sexual behavior. A decade ago, a meta-analysis on findings from nearly 100 studies extracted several conclusions. On average, small but statistically reliable associations between FA and traits of interest exist. Though modest, these associations are expected to greatly underestimate the strength of associations with underlying DI. Despite the massive sample size across studies, we still lack a good handle on which traits are most strongly affected by DI. A major methodological implication of the meta-analysis is that most studies have been, individually, woefully underpowered to detect associations. Though offering some intriguing findings, much research is the past decade too has been underpowered; hence, the newer literature is also likely noisy. Several large-scale studies are exceptions. Future progress depends on additional large-scale studies and researchers' sensitivity to power issues. As well, theoretical assumptions and conceptualizations of DI and FA driving psychological research may need revision to explain empirical patterns.

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.

Hormone ratios suffer from striking lack of robustness to measurement error.

Hormone ratios are often used to capture the joint effect (or "balance") of two hormones with opposing or mutually suppressive effects. Despite some statistical and interpretative problems, hormone ratios are being increasingly used to examine associations of testosterone/cortisol, estradiol/progesterone, testosterone/estradiol, and other hormone pairs. Here we discuss a methodological problem that has not been previously recognized, namely, the striking lack of robustness of raw hormone ratios in the face of measurement error. Hormone levels are measured with error, both due to inability of assays to perfectly assess concentrations "in the tube" and due to discrepancies between levels at the time of sample collection and effective levels that produce the physiological and/or behavioral effect of interest. Noise in measured hormone levels can be substantially exaggerated by ratios, especially when the distribution of the hormone at the denominator is positively skewed, as is frequently observed. To evaluate the extent of this problem and explore the conditions that exacerbate it, we present two sets of simulations, one using idealized distributions and one using empirically observed distributions from studies of estrogen and progesterone. Results show that the validity of raw hormone ratios-the correlation between measured levels and underlying effective levels-drops rapidly in the presence of realistic levels of measurement error. Log-ratios are much more robust to measurement error, and their validity is more stable across samples; under some conditions (e.g., moderate amounts of noise with positively correlated hormone levels), they may provide a more valid measurement of the underlying raw ratio than the measured raw ratio itself. These findings have important implications for research that uses hormone ratios as predictors.

Psychological Science in the Wake of COVID-19: Social, Methodological, and Metascientific Considerations.

The COVID-19 pandemic has extensively changed the state of psychological science from what research questions psychologists can ask to which methodologies psychologists can use to investigate them. In this article, we offer a perspective on how to optimize new research in the pandemic's wake. Because this pandemic is inherently a social phenomenon-an event that hinges on human-to-human contact-we focus on socially relevant subfields of psychology. We highlight specific psychological phenomena that have likely shifted as a result of the pandemic and discuss theoretical, methodological, and practical considerations of conducting research on these phenomena. After this discussion, we evaluate metascientific issues that have been amplified by the pandemic. We aim to demonstrate how theoretically grounded views on the COVID-19 pandemic can help make psychological science stronger-not weaker-in its wake.

Testosterone and romance: the association of testosterone with relationship commitment and satisfaction in heterosexual men and women.

OBJECTIVES: The current study extends previous research on testosterone (T) and mating effort by examining whether relationship commitment and satisfaction explain variance in T beyond relationship status alone. METHODS: Salivary testosterone and self-reported assessments of relationship commitment and satisfaction were assessed among 90 heterosexual men and women (age M = 23.57) in a cross-sectional community sample. RESULTS: Relationship commitment was significantly related to T among men (P < 0.01), with increasing levels of commitment predicting lower T, even among paired men (P < 0.05). In contrast, relationship commitment was not related to women's T (P > 0.05). Controlling for relationship commitment, satisfaction did not predict T levels in men or women (P's > 0.18). CONCLUSIONS: The association of increasing relationship commitment with reduced T levels in men confirms and extends prior research linking T with mating effort. Together with previous research, this study suggests that T does not vary with relationship commitment or quality in monogamous, heterosexual women.

Robust evidence for moderation of ovulatory shifts by partner attractiveness in Arslan et al.'s (2020) data.

Arslan et al. (2020) conducted a large-scale, preregistered daily diary study on over 400 normally ovulating women. Of core interest were hypotheses that women's ratings of their partner's sexual attractiveness moderate associations of fertility status with women's own extrapair sexual desires, their own interest in in-pair sex, and their partners' mate retention tactics. The authors claim that "no evidence for moderator effects" (p. 426) was found. In fact, their own analyses reported in their supplementary material show robust evidence for moderation effects. Moreover, a new reanalysis using a more comprehensive composite measure of male partner sexual attractiveness yielded even stronger results. Effect size estimates are consistent with the existence of large, meaningful moderation effects, revealing that this study actually does show evidence of moderation effects. Additional analyses show similarly strong moderator effects on male proprietariness. We discuss the findings in the context of reliance on binary (significant vs. nonsignificant) labels and the pitfalls of underreporting effects. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Aggress to impress: hostility as an evolved context-dependent strategy.

Given the high costs of aggression, why have people evolved to act aggressively? Comparative biologists have frequently observed links between aggression, status, and mating in nonhuman animals. In this series of experiments, the authors examined the effects of status, competition, and mating motives on men's and women's aggression. For men, status motives increased direct aggression (face-to-face confrontation). Men's aggression was also boosted by mating motives, but only when observers were other men. For women, both status and mating motives increased indirect aggression (e.g., socially excluding the perpetrator). Although neither status nor mating motives increased women's direct aggression, women did become more directly aggressive when motivated to compete for scarce resources. These context- and sex-specific effects on human aggression contribute to a broader understanding of the functional nature of aggressive behavior.

Human oestrus.

For several decades, scholars of human sexuality have almost uniformly assumed that women evolutionarily lost oestrus--a phase of female sexuality occurring near ovulation and distinct from other phases of the ovarian cycle in terms of female sexual motivations and attractivity. In fact, we argue, this long-standing assumption is wrong. We review evidence that women's fertile-phase sexuality differs in a variety of ways from their sexuality during infertile phases of their cycles. In particular, when fertile in their cycles, women are particularly sexually attracted to a variety of features that likely are (or, ancestrally, were) indicators of genetic quality. As women's fertile-phase sexuality shares with other vertebrate females' fertile-phase sexuality a variety of functional and physiological features, we propose that the term oestrus appropriately applies to this phase in women. We discuss the function of women's non-fertile or extended sexuality and, based on empirical findings, suggest ways that fertile-phase sexuality in women has been shaped to partly function in the context of extra-pair mating. Men are particularly attracted to some features of fertile-phase women, but probably based on by-products of physiological changes males have been selected to detect, not because women signal their cycle-based fertility status.

Sex Differences in Detecting Sexual Infidelity : Results of a Maximum Likelihood Method for Analyzing the Sensitivity of Sex Differences to Underreporting.

Despite the importance of extrapair copulation (EPC) in human evolution, almost nothing is known about the design features of EPC detection mechanisms. We tested for sex differences in EPC inference-making mechanisms in a sample of 203 young couples. Men made more accurate inferences (φmen = 0.66, φwomen = 0.46), and the ratio of positive errors to negative errors was higher for men than for women (1.22 vs. 0.18). Since some may have been reluctant to admit EPC behavior, we modeled how underreporting could have influenced these results. These analyses indicated that it would take highly sex-differentiated levels of underreporting by subjects with trusting partners for there to be no real sex difference. Further analyses indicated that men may be less willing to harbor unresolved suspicions about their partners' EPC behavior, which may explain the sex difference in accuracy. Finally, we estimated that women underreported their own EPC behavior (10%) more than men (0%).

Heritability of fluctuating asymmetry in a human twin sample: the effect of trait aggregation.

Fluctuating asymmetry is thought to reflect developmental instability, which may in turn indicate genetically influenced fitness. Controversy surrounding these claims has centered on the extent to which fluctuating asymmetry is heritable. Most studies have estimated its heritability to be very low using single-trait measures. This study uses data from a human twin sample to demonstrate that the heritability estimate resulting from the aggregation of fluctuating asymmetry across multiple traits is non-zero. This is the case even when the estimates of fluctuating asymmetries of the individual traits do not differ significantly from 0.