Recommendations for the study of women in hormones and competition research

Testosterone, gender identity and gender-stereotyped personality attributes

Sex/gender differences in personality associated with gender stereotyped behavior are widely studied in psychology yet remain a subject of ongoing debate. Exposure to testosterone during developmental periods is considered to be a primary mediator of many sex/gender differences in behavior. Extensions of this research has led to both lay beliefs and initial research about individual differences in basal testosterone in adulthood relating to "masculine" personality. In this study, we explored the relationships between testosterone, gender identity, and gender stereotyped personality attributes in a sample of over 400 university students (65 % female assigned at birth). Participants provided ratings of their self-perceived masculinity and femininity, resulting in a continuous measure of gender identity, and a set of agentic and communal personality attributes. A saliva sample was also provided for assay of basal testosterone. Results showed no compelling evidence that basal testosterone correlates with gender-stereotyped personality attributes or explains the relationship between sex/gender identity and these attributes, across, within, or covarying out sex assigned at birth. Contributing to a more gender diverse approach to assessing sex/gender relationships with personality and testosterone, our continuous measure of self-perceived masculinity and femininity predicted additional variance in personality beyond binary sex and showed some preliminary but weak relationships with testosterone. Results from this study cast doubt on the activational testosterone-masculinity hypothesis for explaining sex differences in gender stereotyped traits and within-sex/gender variation in attributes associated with agency and communality.

Salivary testosterone and cortisol response in acute stress modulated by seven sessions of mindfulness meditation in young males

Stress is an established risk factor for negative health outcomes. Salivary cortisol and testosterone concentrations increase in response to acute psychosocial stress. It's crucial to reduce stress for health and well-being through evidence-based interventions. Body-mind interventions such as meditation and Tai Chi have shown reduced cortisol levels but mixed results in testosterone concentration after stress. To address this research gap, we conducted a pilot randomized controlled trial to examine the modulating effects of a short-term (seven 20-minute sessions) mindfulness meditation on testosterone and cortisol in response to acute stress. Using one form of mindfulness meditation - Integrative Body-Mind Training (IBMT) and an active control-relaxation training (RT), we assessed salivary cortisol and testosterone concentrations at three stages of stress intervention - rest, stress, and an additional 20-min IBMT or RT practice. We found increased cortisol and testosterone concentrations after acute stress in both groups, but testosterone rise was not associated with cortisol rise. Moreover, an additional practice immediately after stress produced higher testosterone concentrations in the IBMT group than the RT group, whereas cortisol concentration increased in the RT group than in the IBMT group at the same time point. These findings indicate that brief mindfulness intervention modulates a dual-hormone profile of testosterone and cortisol in response to acute stress presumably via the co-regulation of hypothalamus-pituitary-adrenal and hypothalamus-pituitary-testicular axes.

Women in their mid-follicular phase outcompete hormonal contraceptive users, an effect partially explained by relatively greater progesterone and cortisol reactivity to competition

Early evidence suggests that hormonal contraceptive (HC) use alters psychological functioning and competitive behavior. Yet, there is limited data on endocrine models for explaining how HC use affects these outcomes. In this pre-registered and open-data study, we test if HC users and naturally cycling (NC) females in their low (mid-follicular) and high (mid-luteal) progesterone phase differ in competitive persistence and whether progesterone and cortisol reactivity mediate of this effect. HC users (N = 73) in the active hormone-exposure phase and NC participants in the mid-follicular (N = 69) or mid-luteal (N = 72) phase completed two behavioral measures of competitive persistence, holding up a weight for time followed by attempting to solve an unsolvable anagram. Participants also completed measures of handgrip strength and self-reported competitiveness as well as gave saliva samples before and after the tasks for hormone assay. Results showed that NC-follicular group had greater competitive persistence in the weight-holding task compared to both NC-luteal (d = 0.38) and HC use (d = 0.43) groups independent of physical strength and self-reported competitiveness covariates. Although anagram task performance showed similar trends for group differences, analyses for this task were inconclusive. Baseline progesterone did not mediate the effect of cycle phase group on competitive persistence. HC users showed relatively blunted cortisol and progesterone reactivity, and this effect partially mediated the difference in competitive persistence between HC users and the NC-follicular group. In sum, results suggest that HC use could downregulate competitive behavior at least partly by dampening cortisol-progesterone reactivity. These findings offer a new endocrine model for understanding HC use and cycle phase effects on motivational and energetic outcomes required for optimal performance in competitive contexts.

Testosterone promotes dominance behaviors in the Ultimatum Game after players' status increases

Although testosterone is generally considered to promote dominance behaviors, in humans it fosters behaviors appropriate to achieving and maintaining social status, contingent upon the situation. Recent cross-sectional studies, such as Inoue et al. (Sci Rep 7:5335, 2017), have shown that dominance behaviors induced by testosterone are modulated by high status. Yet, it remains ambiguous whether a rise in social status within real-world social groups reshapes the relationship between testosterone and dominance behavior. To investigate this longitudinal question, we added a second wave to Inoue et al.'s study, collecting further data after an interval of 2 years. Members of a university rugby team that adheres to a rigid hierarchical order rooted in seniority played the Ultimatum Game with teammates and provided saliva for assays of testosterone and cortisol. Our analysis reveals that individuals with higher baseline salivary testosterone levels exhibited more dominance as their position in the hierarchy increased according to their seniority.

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

Introduction

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

Objective

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

Methodology

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

Results

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

Conclusion

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

Fertility predicts self-development-oriented competitiveness in naturally cycling women but not hormonal contraceptive users

Objective

A growing body of research has begun investigating the relationship between hormones and female competitiveness. Many researchers have focused on the effect of the menstrual cycle and hormonal contraceptives. Despite many attempts at understanding hormone-behavior associations, contradictory findings have made it difficult to determine the existence of true effects. The aim of the current research was to use a robust methodological design to investigate the effect of fertility probability on four competitive orientations in naturally cycling women and hormonal contraceptive users.

Methods

Using a longitudinal diary study with over 3,900 observations from 21 countries, we explore the effect of fertility probability on four self-report competitive orientations after controlling for menstruation: self-developmental competition, hyper competitiveness, competition avoidance, and lack of interest toward competition.

Results

Using Bayesian estimation for ordinal mixed models, we found that fertility probability was associated with an increase in self-development competitiveness amongst naturally cycling women but not hormonal contraceptive users. We also found weak evidence that hormonal contraceptive users show reduced interest in competing compared to naturally cycling women. There were no other robust effects of fertility or hormonal contraceptive use.

Conclusions

These results suggest that fertility probability is associated with increased fluctuations in self-development competitive motivation and that hormonal contraceptives interfere with this effect. This research contributes to the growing body of literature suggesting that hormonal contraceptives may influence psychology and behavior by disrupting evolved hormonal mechanisms.

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

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

Testosterone fluctuations in response to a democratic election predict partisan attitudes toward the elected leader

Intergroup competitions such as democratic elections can intensify intergroup polarization and conflict. Partisan attitudes toward the elected leader can also shift from before to after an election, but the biology underlying these attitudinal shifts remains largely unknown. An important factor could be the hormone testosterone, which is theorized to fluctuate during competition and to influence status seeking. In a naturalistic study of 113 registered voters, we measured changes in testosterone levels and attitudes toward the winner of the 2012 US Presidential Election. We found that supporters of the losing candidate (Mitt Romney) showed acute increases in testosterone levels compared to supporters of the winner (Barack Obama) on the evening of Election Day. Supporters of the losing candidate also demonstrated flatter diurnal testosterone slopes on Election Day that persisted up to two days after the election. Furthermore, greater increases in acute testosterone levels and flatter diurnal slopes among supporters of the losing candidate were associated with less positive evaluations of the winning candidate. These testosterone-moderated attitudinal shifts observed in the days after the election showed a directionally similar pattern with a weaker effect size six months later. Finally, we confirmed that the main results were robust to alternative data analytic choices using multiverse specification curve analysis. The findings from this paper suggest that hormonal responses to large-scale intergroup competitions may shape how we perceive our elected leaders, shedding light on the biology of intergroup relations.

Intranasal oxytocin, testosterone reactivity, and human competitiveness

Competitiveness is an essential feature of human social interactions. Despite an extensive body of research on the underlying psychological and cultural factors regulating competitive behavior, the role of biological factors remains poorly understood. Extant research has focused primarily on sex hormones, with equivocal findings. Here, we examined if intranasal administration of the neuropeptide oxytocin (OT) - a key regulator of human social behavior and cognition - interacts with changes in endogenous testosterone (T) levels in regulating the willingness to engage in competition. In a double-blind placebo-control design, 204 subjects (102 females) self-administrated OT or placebo and were assessed for their willingness to compete via an extensively-validated economic laboratory competition paradigm, in which, before completing a set of incentivized arithmetic tasks, subjects are asked to decide what percentage of their payoffs will be based on tournament paying-scheme. Salivary T concentrations (n = 197) were measured throughout the task to assess endogenous reactivity. Under both OT and placebo, T-reactivity during competition was not associated with competitiveness in females. However, in males, the association between T-reactivity and competitiveness was OT-dependent. That is, males under placebo demonstrated a positive correlation between T-reactivity and the willingness to engage in competition, while no association was observed in males receiving OT. The interaction between OT, T-reactivity, and sex on competitive preferences remained significant even after controlling for potential mediators such as performance, self-confidence, and risk-aversion, suggesting that this three-way interaction effect was specific to competitive motivation rather than to other generalized processes. These findings deepen our understanding of the biological processes underlying human preferences for competition and extend the evidence base for the interplay between hormones in affecting human social behavior.

Status does not predict stress: Women in an egalitarian hunter-gatherer society

It is widely believed that there is strong association between physiological stress and an individual's social status in their social hierarchy. This has been claimed for all humans cross-culturally, as well as in non-human animals living in social groups. However, the relationship between stress and social status has not been explored in any egalitarian hunter-gatherer society; it is also under investigated in exclusively female social groups. Most of human evolutionary history was spent in small, mobile foraging bands of hunter-gatherers with little economic differentiation - egalitarian societies. We analysed women's hair cortisol concentration along with two domains of women's social status (foraging reputation and popularity) in an egalitarian hunter-gatherer society, the Hadza. We hypothesized that higher social status would be associated with lower physiological indicators of stress in these women. Surprisingly, we did not find any association between either foraging reputation or popularity and hair cortisol concentration. The results of our study suggest that social status is not a consistent or powerful predictor of physiological stress levels in women in an egalitarian social structure. This challenges the notion that social status has the same basic physiological implications across all demographics and in all human societies.

Salivary aldosterone and cortisone respond differently to high- and low-psychologically stressful soccer competitions

Aldosterone and cortisone are released in response to physical and psychological stress. However, aldosterone and cortisone responses in children engaged in physical competition have not been described. We examined salivary aldosterone and salivary cortisone responses among Hong Kongese boys, aged 8-11 years, during (1) a soccer match against unknown competitors (N = 84, high psychological stress condition) and (2) an intrasquad soccer scrimmage against teammates (N = 81, low psychological stress condition). Aldosterone levels increased during the soccer match and intrasquad soccer scrimmage conditions, consistent with the view that aldosterone responds to physical stress. During the soccer match, winning competitors experienced larger increases in aldosterone compared to losing competitors, indicating that the degree of aldosterone increase was attenuated by match outcome. Cortisone increased during the soccer match and decreased during the intrasquad soccer scrimmage. Competitors on teams that resulted in a tie had larger cortisone increases compared to winners or losers. These findings highlight that the degree of cortisone change is related to boy's cognitive appraisal of the competitor type (i.e., teammates vs. unknown competitors) and the competitive nature of the game (e.g., tie). These results shed new light on adrenal hormone mediators of stress and competition during middle childhood.

Testosterone reactivity to competition and competitive endurance in men and women

Transient shifts in testosterone occur during competition and are thought to positively influence dominance behavior aimed at enhancing social status. However, individual differences in testosterone reactivity to status contests have not been well-studied in relation to real-time expressions of competitive behavior among men and women. This research tests the association between changes in endogenous testosterone levels during competition and performance in terms of competitive endurance. Participant sex, social presence, and relative status outcomes (e.g., winning vs. losing) are tested as moderators of this relationship. In two studies, men and women (total N = 398) competed in the competitive will task (timed weight-holding) either individually or in the presence of an opponent (Study 1) or as a team with and without the presence of a competitor team (Study 2). Results showed a positive relationship between testosterone reactivity and performance for men, particularly those who won or ranked highest among their group - with increasing testosterone predicting better performance and decreasing testosterone predicting worse performance. For women, the effect only emerged among individuals who competed in dyads and lost. In Study 2, an exploratory mediation analysis revealed that individual differences in trait dominance predicted both testosterone reactivity to competition and task performance, with testosterone reactivity (moderated by sex and status outcome) partially explaining the direct relationship between dominance-related traits and behavior. Our goal was to examine testosterone reactivity in relation to real-time competitive effort and highlight the potential role of this relationship in explaining how individual differences in trait dominance produce competitive behavior.

Beyond the challenge hypothesis: The emergence of the dual-hormone hypothesis and recommendations for future research

The challenge hypothesis makes specific predictions about the association between testosterone and status-seeking behaviors, but the findings linking testosterone to these behaviors are often inconsistent. The dual-hormone hypothesis was developed to help explain these inconsistencies. Specifically, according to this hypothesis, testosterone's association with status-seeking behavior depends on levels of cortisol. Here, we (1) describe the dual-hormone hypothesis in relation to the challenge hypothesis; (2) review recent studies that tested the dual-hormone hypothesis as well as meta-scientific evidence of heterogeneous dual-hormone findings across studies; (3) discuss potential explanations for this heterogeneity, including methodological considerations, contextual factors, and individual differences; and (4) provide recommendations for new work aimed at testing and extending the dual-hormone hypothesis.

Challenging the Top Player: A Preliminary Study on Testosterone Response to An Official Chess Tournament

According to the Challenge Hypothesis, high levels of testosterone (T) are associated with status-seeking behaviors, especially in competitive situations. However, there have not been many studies about rivals' social status and pre-competition neuroendocrine responses. The aim of this study was to analyze whether the participants in a chess tournament showed different pre-match testosterone and cortisol levels depending on differences in ELO (i.e., the International Chess Federation rating to rank the competitive potential and social status between players). The sample was six male participants (mean ± SD) aged 25.5 ± 8.4 years with experience in official tournaments of 16.33 ± 5.72 years and an average ELO rating of 2217.67 ± 112.67. Saliva samples were collected before each round for hormonal determination when participants competed against a rival with a different ELO rating. After five competition rounds per participant, higher rival pre-competition T concentrations were shown when playing against the best-rated participant, but there were no differences in cortisol (C). The multilevel model confirmed rises in rivals' precompetitive T levels modulated by the difference in the opponent´s ELO rating. No significant changes were observed in C. The results suggest that the rival´s status can determine the opponent´s anticipatory neuroendocrine responses to an official chess tournament.

Hormonal and emotional responses to competition using a dyadic approach: Basal testosterone predicts emotional state after a defeat

The present study analyzes the testosterone (T), cortisol (C) and emotional response in competitive interactions between dyads, as well as the relationship between basal T and the emotional response. Seventy-two men and women (36 dyads) participated in same-sex dyads in a face-to-face laboratory competition, and thirty-two men and women (16 dyads) carried out the same task in a non-competitive condition. Salivary samples (5 ml of saliva, plastic vials) were provided at three time points (baseline, task, and post-task), and subsequently T (pg/ml) and C (nmol/L) concentrations were measured using ELISA method. Participants completed self-reported measures of emotional valence, emotional arousal and perceived dominance by means of the Self-Assessment Manikin (SAM), at three time points (pre-task, task, and post-task). Two-level crossed Multilevel Models (MLM) showed a participants' stability in C (Mean ± SEM: baseline: 3.84 ± 0.28, task: 2.92 ± 0.28 and post-task: 2.62 ± 0.3), emotional valence (pre-task: 4 ± 0.06, task: 3.66 ± 0.1 and post-task: 3.84 ± 0.09), arousal (pre-task: 3.29 ± 0.09, task: 3.83 ± 0.09 and post-task: 3.38 ± 0.1) and dominance (pre-task: 3.28 ± 0.08, task: 3.4 ± 0.1 and post-task: 3.44 ± 0.09) values, which in the case of emotional valence and dominance was modulated by time-point, outcome and sex. Furthermore, analyses revealed that opponents' C, arousal and dominance values at one time-point influenced participants' values at the following time-point modulated by outcome, sex and time-point. Moreover, MLM indicated that in loser men, individuals higher in basal T (126.31 ± 6.4) displayed higher negative emotional valence after the defeat (post-task: 3.6 ± 0.21), while in women basal T (99.78 ± 12.6) was not significantly related to post competition emotional valence. These findings reinforce the importance of studying the relationship between hormonal and psychological changes in dyadic competition, and confirm that men and women differ in their psychophysiological responses to competition.

Basal testosterone's relationship with dictator game decision-making depends on cortisol reactivity to acute stress: A dual-hormone perspective on dominant behavior during resource allocation

The dual-hormone hypothesis proposes that testosterone's relationship with status-seeking behavior is moderated by cortisol. However, research testing this hypothesis has focused on basal cortisol; the potential moderating effect of the acute cortisol response to stress has been largely overlooked. The present research investigated the moderating role of cortisol responses to an acute stressor on basal testosterone's link with dominant, status-relevant decision-making. Also, given the multifaceted nature of the response to acute stress, cardiovascular and affective responses to the stressor were examined as alternative moderators of the testosterone-behavior relationship. Participants (N = 112; 56% female) were exposed to a social-evaluative stressor, and their stress responses were measured. Participants subsequently engaged in a one-shot dictator game, wherein they were asked to split money ($10) with a confederate counterpart. The amount of money participants decided to keep for themselves was treated as a metric of dominant status-seeking behavior. For individuals who demonstrated lower cortisol responses to the stressor, basal testosterone was positively associated with more dominant behavior (i.e., keeping more money for oneself), but for those who showed higher cortisol responses, the testosterone-behavior relationship was suppressed. Moreover, other aspects of the stress response (i.e., cardiovascular and affective responses) did not moderate the relationship between basal testosterone and dictator game behavior. These results provide unique support for the dual-hormone hypothesis using markers of stress-induced cortisol change. The findings also suggest that the antagonistic effects of stress on testosterone's role in motivating status-relevant behavior may be specific to cortisol's role in the acute stress response.

Is Man the Measure of All Things? A Social Cognitive Account of Androcentrism

Androcentrism refers to the propensity to center society around men and men's needs, priorities, and values and to relegate women to the periphery. Androcentrism also positions men as the gender-neutral standard while marking women as gender-specific. Examples of androcentrism include the use of male terms (e.g., he), images, and research participants to represent everyone. Androcentrism has been shown to have serious consequences. For example, women's health has been adversely affected by over-generalized medical research based solely on male participants. Nonetheless, relatively little is known about androcentrism's proximate psychological causes. In the present review, we propose a social cognitive perspective arguing that both social power and categorization processes are integral to understanding androcentrism. We present and evaluate three possible pathways to androcentrism deriving from (a) men being more frequently instantiated than women, (b) masculinity being more "ideal" than femininity, and/or (c) masculinity being more common than femininity.