Human Male Body Size Predicts Increased Knockout Power, Which Is Accurately Tracked by Conspecific Judgments of Male Dominance.

Humans have undergone a long evolutionary history of violent agonistic exchanges, which would have placed selective pressures on greater body size and the psychophysical systems that detect them. The present work showed that greater body size in humans predicted increased knockout power during combative contests (Study 1a-1b: total N = 5,866; Study 2: N = 44 openweight fights). In agonistic exchanges reflective of ancestral size asymmetries, heavier combatants were 200% more likely to win against their lighter counterparts because they were 200% more likely to knock them out (Study 2). Human dominance judgments (total N = 500 MTurkers) accurately tracked the frequency with which men (N = 516) knocked out similar-sized adversaries (Study 3). Humans were able to directly perceive a man's knockout power because they were attending to cues of a man's body size. Human dominance judgments-which are important across numerous psychological domains, including attractiveness, leadership, and legal decision-making-accurately predict the likelihood with which a potential mate, ally, or rival can incapacitate their adversaries.

Preliminary evidence of an increased susceptibility to face pareidolia in postpartum women.

As primates, we are hypersensitive to faces and face-like patterns in the visual environment, hence we often perceive illusory faces in otherwise inanimate objects, such as burnt pieces of toast and the surface of the moon. Although this phenomenon, known as face pareidolia, is a common experience, it is unknown whether our susceptibility to face pareidolia is static across our lifespan or what factors would cause it to change. Given the evidence that behaviour towards face stimuli is modulated by the neuropeptide oxytocin (OT), we reasoned that participants in stages of life associated with high levels of endogenous OT might be more susceptible to face pareidolia than participants in other stages of life. We tested this hypothesis by assessing pareidolia susceptibility in two groups of women; pregnant women (low endogenous OT) and postpartum women (high endogenous OT). We found evidence that postpartum women report seeing face pareidolia more easily than women who are currently pregnant. These data, collected online, suggest that our sensitivity to face-like patterns is not fixed and may change throughout adulthood, providing a crucial proof of concept that requires further research.

Hierarchical status is rapidly assessed from behaviourally dominant faces.

Recognition of social hierarchy is a key feature that helps us navigate through our complex social environment. Neuroimaging studies have identified brain structures involved in the processing of hierarchical stimuli, but the precise temporal dynamics of brain activity associated with such processing remains largely unknown. In this investigation, we used event-related potentials (ERPs) to examine the effect of social hierarchy on the neural responses elicited by dominant and nondominant faces. Participants played a game where they were led to believe that they were middle-rank players, responding alongside other alleged players, whom they perceived as higher or lower-ranking. ERPs were examined in response to dominant and nondominant faces, and low-resolution electromagnetic tomography (LORETA) was used to identify the implicated brain areas. The results revealed that the amplitude of the N170 component was enhanced for faces of dominant individuals, showing that hierarchy influences the early stages of face processing. A later component, the late positive potential (LPP) appearing between 350-700 ms, also was enhanced for faces of higher-ranking players. Source localisation suggested that the early modulation was due to an enhanced response in limbic regions. These findings provide electrophysiological evidence for enhanced early visual processing of socially dominant faces.

The social predictors of paternal antenatal mental health and their associations with maternal mental health in the Queensland Family Cohort prospective study.

Antenatal depression (AND) affects 1 in 10 fathers, potentially negatively impacting maternal mental health and well-being during and after the transition to parenthood. However, few studies have assessed the social predictors of paternal AND or their possible associations with maternal mental health. We analysed data from 180 couples participating in the Queensland Family Cohort longitudinal study. Both parents completed surveys measuring mental health, relationship quality, social support, and sleep quality at 24 weeks of pregnancy. Mothers also completed the same surveys 6 weeks' postpartum. Antenatal depression, stress, and anxiety were highest among fathers reporting lower social support and higher sleep impairment. Maternal AND, stress, and anxiety were higher among mothers reporting higher physical pain and poor sleep quality. Postnatally, mothers reporting lower social support also reported higher depression, anxiety, stress, and psycho-social well-being. While there were no significant associations between AND among fathers and maternal antenatal or postnatal depression, an exploratory analysis revealed that mothers whose partners reported lower antenatal social support also reported lower postnatal social support and higher postnatal depression. Our findings highlight the importance of including data among fathers to achieve a whole family approach to well-being during the transition to parenthood.

Human third-party observers accurately track fighting skill and vigour along their unique paths to victory.

Sexual selection via male-male contest competition has shaped the evolution of agonistic displays, weaponry, and fighting styles, and is further argued to have shaped human psychological mechanisms to detect, process, and respond appropriately to cues of fighting ability. Drawing on the largest fight-specific dataset to date across the sports and biological sciences (N = 2765 fights), we examined how different indicators of fighting ability in humans reflect unique paths to victory and indicate different forms of perceived and actual resource-holding power (RHP). Overall, we discovered that: (1) both striking skill and vigour, and grappling skill and vigour, individually and collectively predict RHP; (2) different RHP indicators are distinguished by a unique path to victory (e.g., striking skill is a knockout-typical strategy, whereas grappling vigour is a submission-typical strategy); and (3) third-party observers accurately track fighting skill and vigour along their unique paths to victory. Our argument that different measures of RHP are associated with unique paths to victory, and third-party observers accurately track fighting vigour and skill along their unique paths to victory, advance our understanding not only of human contest competition, but animal contest theory more broadly.

Associations between COVID-19 lockdown and post-lockdown on the mental health of pregnant women, postpartum women and their partners from the Queensland family cohort prospective study.

BACKGROUND: There are very few developed countries where physical isolation and low community transmission has been reported for COVID-19 but this has been the experience of Australia. The impact of physical isolation combined with low disease transmission on the mental health of pregnant women is currently unknown and there have been no studies examining the psychological experience for partners of pregnant women during lockdown. The aim of the current study was to examine the impact of the first COVID-19 lockdown in March 2020 and post lockdown from August 2020 on the mental health of pregnant women or postpartum women and their partners. METHODS: Pregnant women and their partners were prospectively recruited to the study before 24 weeks gestation and completed various questionnaires related to mental health and general wellbeing at 24 weeks gestation and then again at 6 weeks postpartum. The Depression, Anxiety and Stress Scale (DASS-21) and the Edinburgh Postnatal Depression Scale (EPDS) were used as outcome measures for the assessment of mental health in women and DASS-21 was administered to their partners. This analysis encompasses 3 time points where families were recruited; before the pandemic (Aug 2018-Feb 2020), during lockdown (Mar-Aug 2020) and after the first lockdown was over (Sept-Dec 2020). RESULTS: There was no significant effect of COVID-19 lockdown and post lockdown on depression or postnatal depression in women when compared to a pre-COVID-19 subgroup. The odds of pregnant women or postpartum women experiencing severe anxiety was more than halved in women during lockdown relative to women in the pre-COVID-19 period (OR = 0.47; 95%CI: 0.27-0.81; P = 0.006). Following lockdown severe anxiety was comparable to the pre-COVID-19 women. Lockdown did not have any substantial effects on stress scores for pregnant and postpartum women. However, a substantial decrease of over 70% in the odds of severe stress was observed post-lockdown relative to pre-COVID-19 levels. Partner's depression, anxiety and stress did not change significantly with lockdown or post lockdown. CONCLUSION: A reproductive age population appear to be able to manage the impact of lockdown and the pandemic with some benefits related to reduced anxiety.

Facial hair may slow detection of happy facial expressions in the face in the crowd paradigm.

Human visual systems have evolved to extract ecologically relevant information from complex scenery. In some cases, the face in the crowd visual search task demonstrates an anger superiority effect, where anger is allocated preferential attention. Across three studies (N = 419), we tested whether facial hair guides attention in visual search and influences the speed of detecting angry and happy facial expressions in large arrays of faces. In Study 1, participants were faster to search through clean-shaven crowds and detect bearded targets than to search through bearded crowds and detect clean-shaven targets. In Study 2, targets were angry and happy faces presented in neutral backgrounds. Facial hair of the target faces was also manipulated. An anger superiority effect emerged that was augmented by the presence of facial hair, which was due to the slower detection of happiness on bearded faces. In Study 3, targets were happy and angry faces presented in either bearded or clean-shaven backgrounds. Facial hair of the background faces was also systematically manipulated. A significant anger superiority effect was revealed, although this was not moderated by the target's facial hair. Rather, the anger superiority effect was larger in clean-shaven than bearded face backgrounds. Together, results suggest that facial hair does influence detection of emotional expressions in visual search, however, rather than facilitating an anger superiority effect as a potential threat detection system, facial hair may reduce detection of happy faces within the face in the crowd paradigm.

Facial width-to-height ratio predicts fighting success: A direct replication and extension of Zilioli et al. (2014).

Zilioli et al. (2014) were the first to show an association between male facial width-to-height ratio (fWHR) and physical aggression and fighting ability in professional mixed-martial-arts fighters. Here, we re-examined this relationship by replicating (using all original measures) and extending (using 23 new variables related to fighting performance) Zilioli et al. (2014) in a statistically well-powered sample of 520 fighters using automatic and manual measures of the fWHR involving both eyelid and eyebrow landmarks, used interchangeably in previous reports (Studies 1-2). Most importantly, we successfully replicated Zilioli et al.'s (2014) central finding that fighters' fWHR, when manually calculated using the eyebrow landmark, predicted their fighting success (p = .004, controlling for body mass index and total fights). Consistent with past criticisms of using fight rather than fighter data to examine fighting success, which have argued that individual fights can be suddenly and unexpectedly determined and do not capture an individual's overall ability to succeed, Study 3 (N = 1367 fights) found no association between fWHR and singular victories. Studies 1-3 showed continual evidence that larger fWHRs were associated with grappling abilities, even after controlling for demographic and allometric factors. Strikingly, Study 3 discovered associations between all fWHR measures and grappling skill that remained robust before and after controlling for 17 different control variables. We discuss that grappling, or the act of taking down an opponent, involves a more aggressive, close-combat approach than does striking. Combined, these results offer additional support for the argument that fWHR may have been shaped by sexual selection.

A branded bandage is worth a thousand words: blood branded bandages signal men's generosity and morality.

BACKGROUND AND OBJECTIVE: Recruiting and retaining male donors remain an ongoing challenge for blood collection agencies. Research suggests that interventions based on costly signalling theory that allows donors to unobtrusively but publicly signal their donor status may be effective. However, what functions as such a signal and how it is interpreted has not been determined. MATERIALS AND METHODS: A total of 242 Australian residents (127 female; 115 male) recruited through an online research platform rated their perceptions of a male target wearing (a) no bandage, (b) a regular unmarked bandage or (c) a blood donor branded bandage. RESULTS: The target wearing a blood donor branded bandage was rated as significantly more generous by female participants and moral compared to both the target who wore no bandage and the target wearing a regular unmarked bandage. The target wearing the unmarked bandage was perceived as significantly less healthy and competent compared to the target not wearing a bandage. CONCLUSION: A public signal of public donor status conveys the generosity and morality of the wearer. The bandage applied to donors after they have donated can act as such an effective signal, but only when these bandages are clearly branded as resulting from donating blood.

Papa Don't Preach? : Using Lies to Expose the Truth about Who Suppresses Female Sexuality.

The suppression of sexuality is culturally widespread, and women's sexual promiscuity, activity, and enjoyment are almost always judged and punished more harshly than men's. It remains disputed, however, to what end people suppress sexuality, and who benefits from the suppression of female sexuality. Different theories predict that women in general, men in general, women's intimate partners, or parents benefit most. Here we use the lies women and men tell-or imagine telling-about their sexual histories as an indirect measure of who is most involved in the suppression of sexuality. We asked men and women what they would reply if asked questions by their mother, father, current partner, attractive confederate, and various same- or opposite-sex friends and colleagues about their number of previous sex partners, age at first romantic kiss, age at first consensual sex, and cheating on a previous partner or spouse. By comparing the size and direction of the lies that subjects told, we tested competing predictions of several cultural and evolutionary theories concerning why female sexuality is suppressed and who is driving its suppression. We found that men and women told larger and more frequent lies to their parents, with women telling the largest and most frequent lies of all to their fathers. Additionally, the majority of lies by both men and women were in sexually conservative directions. Our findings suggest that mothers, and especially fathers, restrict female sexuality.

A multivariate analysis of women's mating strategies and sexual selection on men's facial morphology.

The strength and direction of sexual selection via female choice on masculine facial traits in men is a paradox in human mate choice research. While masculinity may communicate benefits to women and offspring directly (i.e. resources) or indirectly (i.e. health), masculine men may be costly as long-term partners owing to lower paternal investment. Mating strategy theory suggests women's preferences for masculine traits are strongest when the costs associated with masculinity are reduced. This study takes a multivariate approach to testing whether women's mate preferences are context-dependent. Women (n = 919) rated attractiveness when considering long-term and short-term relationships for male faces varying in beardedness (clean-shaven and full beards) and facial masculinity (30% and 60% feminized, unmanipulated, 30% and 60% masculinized). Participants then completed scales measuring pathogen, sexual and moral disgust, disgust towards ectoparasites, reproductive ambition, self-perceived mate value and the facial hair in partners and fathers. In contrast to past research, we found no associations between pathogen disgust, self-perceived mate value or reproductive ambition and facial masculinity preferences. However, we found a significant positive association between moral disgust and preferences for masculine faces and bearded faces. Preferences for beards were lower among women with higher ectoparasite disgust, providing evidence for ectoparasite avoidance hypothesis. However, women reporting higher pathogen disgust gave higher attractiveness ratings for bearded faces than women reporting lower pathogen disgust, providing support for parasite-stress theories of sexual selection and mate choice. Preferences for beards were also highest among single and married women with the strongest reproductive ambition. Overall, our results reflect mixed associations between individual differences in mating strategies and women's mate preferences for masculine facial traits.

Heterogeneity in the Sexual Orientations of Men Who Have Sex with Fa'afafine in Samoa.

In Samoa, feminine natal males who possess male-typical genitalia are known locally as fa'afafine. Some Samoan men express sexual interest in fa'afafine, whereas others do not. To assess the sexual orientation of men who are sexually interested in fa'afafine, we collected sexual attraction ratings and viewing times of Samoan men's and women's faces. Study 1 (N = 130) focused on men who were insertive or versatile during anal sex with fa'afafine partners. These men were compared to each other, as well as to males (i.e., men and fa'afafine) who were exclusively sexually interested in either women or men. Study 2 (N = 180) compared men who had sex with fa'afafine and women; men who had sex with fa'afafine, women, and men; and men who had sex with fa'afafine and men. These men were compared to each other, as well as to males who were exclusively sexually interested in either women or men. These studies suggest that men who have sex with fa'afafine are a heterogeneous group. A small portion of the men who are sexually interested in fa'afafine shows a relatively bisexual pattern of sexual attraction ratings and viewing times, namely men who have sex with fa'afafine, men, and women. In contrast, a larger number of men who were sexually interested in fa'afafine responded in a manner similar to men who were exclusively sexually interested in either women or men. The present research suggests that additional insights into male sexual orientation can be garnered by focusing on how sexuality is expressed in non-Western cultural contexts.

Mating Strategies and the Masculinity Paradox: How Relationship Context, Relationship Status, and Sociosexuality Shape Women's Preferences for Facial Masculinity and Beardedness.

According to the dual mating strategy model, in short-term mating contexts women should forego paternal investment qualities in favor of mates with well-developed secondary sexual characteristics and dominant behavioral displays. We tested whether this model explains variation in women's preferences for facial masculinity and beardedness in male faces. Computer-generated composites that had been morphed to appear ± 50% masculine were rated by 671 heterosexual women (M age = 31.72 years, SD = 6.43) for attractiveness when considering them as a short-term partner, long-term partner, a co-parent, or a friend. They then completed the Revised Sociosexual Inventory (SOI-R) to determine their sexual openness on dimensions of desire, behavior, and attitudes. Results showed that women's preferences were strongest for average facial masculinity, followed by masculinized faces, with feminized faces being least attractive. In contrast to past research, facial masculinity preferences were stronger when judging for co-parenting partners than for short-term mates. Facial masculinity preferences were also positively associated with behavioral SOI, negatively with desire, and were unrelated to global or attitudinal SOI. Women gave higher ratings for full beards than clean-shaven faces. Preferences for beards were higher for co-parenting and long-term relationships than short-term relationships, although these differences were not statistically significant. Preferences for facial hair were positively associated with global and attitudinal SOI, but were unrelated to behavioral SOI and desire. Although further replication is necessary, our findings indicate that sexual openness is associated with women's preferences for men's facial hair and suggest variation in the association between sociosexuality and women's facial masculinity preferences.

Mothers are sensitive to men's beards as a potential cue of paternal investment.

Mating strategy theories assert that women's preferences for androgen dependent traits in men are stronger when the costs of reduced paternal investment are lowest. Past research has shown that preferences for facial masculinity are stronger among nulliparous and non-pregnant women than pregnant or parous women. In two studies, we examine patterns in women's preferences for men's facial hair - likely the most visually conspicuous and sexually dimorphic of men's secondary sexual traits - when evaluating men's masculinity, dominance, age, fathering, and attractiveness. Two studies were conducted among heterosexual pregnant women, mothers, non-contractive and contraceptive users. Study 1 used a between-subjects sample (N = 2103) and found that mothers had significantly higher preferences for beards when judging fathering than all other women. Pregnant women and mothers also judged beards as more masculine and older, but less attractive, than non-contractive and contraceptive users. Parous women judged beards higher for age, masculinity and fathering, but lower for attractiveness, than nulliparous women. Irrespective of reproductive status, beards were judged as looking more dominant than clean-shaven faces. Study 2 used a within-subjects design (N = 53) among women surveyed during pregnancy and three months post-partum. Judgments of parenting skills were higher for bearded stimuli during pregnancy among women having their first baby, whereas among parous women parenting skills judgments for bearded stimuli were higher post-partum. Our results suggest that mothers are sensitive to beardedness as a masculine secondary sexual characteristic that may denote parental investment, providing evidence that women's mate preferences could reflect sexual selection for direct benefits.

The Interplay Between Economic Status and Attractiveness, and the Importance of Attire in Mate Choice Judgments.

Desirable characteristics of "opposite sex others," such as physical attractiveness and economic status, can influence how individuals are judged, and this is different for men and women. However, under various social contexts where cues of higher or lower economic status is suggested, sex differences in judgments related to mate choice have not been fully explored. In two studies, ratings of economic status and attractiveness were quantified for male and female targets that were presented under various social contexts. Study 1 assessed judgments (n = 1,359) of images of nine male and nine female targets in different sized groups containing only opposite-sex others (i.e., group size). While we found no significant effects of group size on male and female attractiveness, target female economic status increased when surrounded by two or more men. An ad hoc analysis controlling for the attire of the targets (business or casual) found that the association between target female economic status and group size occurred when females were in business attire. Study 2 investigates this effect further by presenting images of 12 males and 12 females, in higher and lower status attire (i.e., business and casual clothing) and measured judgments of attractiveness and economic status among women and men (n = 1,038). Consistent with the results of Study 1, female economic status was only affected when women were in business attire. However, female economic status decreased when in the presence of other men in business attire. There were no sex differences in judgments of economic status when judging stimuli in casual attire. Additionally, negative associations between attractiveness and economic status were found for males presented in casual attire. We discuss these results in the light of evolutionary sexual conflict theory by demonstrating how the asymmetrical importance of status between men and women can influence mate choice judgments.

Women's preferences for men's facial masculinity are strongest under favorable ecological conditions.

The strength of sexual selection on secondary sexual traits varies depending on prevailing economic and ecological conditions. In humans, cross-cultural evidence suggests women's preferences for men's testosterone dependent masculine facial traits are stronger under conditions where health is compromised, male mortality rates are higher and economic development is higher. Here we use a sample of 4483 exclusively heterosexual women from 34 countries and employ mixed effects modelling to test how social, ecological and economic variables predict women's facial masculinity preferences. We report women's preferences for more masculine looking men are stronger in countries with higher sociosexuality and where national health indices and human development indices are higher, while no associations were found between preferences and indices of intra-sexual competition. Our results show that women's preferences for masculine faces are stronger under conditions where offspring survival is higher and economic conditions are more favorable.

Sexual Selection, Agonistic Signaling, and the Effect of Beards on Recognition of Men's Anger Displays.

The beard is arguably one of the most obvious signals of masculinity in humans. Almost 150 years ago, Darwin suggested that beards evolved to communicate formidability to other males, but no studies have investigated whether beards enhance recognition of threatening expressions, such as anger. We found that the presence of a beard increased the speed and accuracy with which participants recognized displays of anger but not happiness (Experiment 1, N = 219). This effect was not due to negative evaluations shared by beardedness and anger or to negative stereotypes associated with beardedness, as beards did not facilitate recognition of another negative expression, sadness (Experiment 2, N = 90), and beards increased the rated prosociality of happy faces in addition to the rated masculinity and aggressiveness of angry faces (Experiment 3, N = 445). A computer-based emotion classifier reproduced the influence of beards on emotion recognition (Experiment 4). The results suggest that beards may alter perceived facial structure, facilitating rapid judgments of anger in ways that conform to evolutionary theory.

Viewing Time and Self-Report Measures of Sexual Attraction in Samoan Cisgender and Transgender Androphilic Males.

Across cultures, androphilic males (natal males who are predominantly sexually attracted to adult men, not women) tend to present in one of two forms: cisgender or transgender. Previous research has shown that, although their gender presentation and identities are distinct, the two forms are similar in many other ways. The present study examined whether cisgender and transgender androphilic males exhibit a similar pattern of self-reported sexual attraction and viewing time response to images of men and women, and one that is directly inverse to that of cisgender gynephilic males (natal males who are predominately sexually attracted to adult women, not men). Using measures of self-reported sexual attraction and viewing time, we compared the response patterns of Samoan cisgender males who self-identified as men, were predominantly attracted to men, and had sex only with men (N = 16) and Samoan transgender males who self-identified as fa'afafine, were predominantly attracted to men, and had sex only with men (N = 30). Samoan cisgender males who self-identified as men, were predominantly attracted to women, and had sex only with women (N = 31) served as a comparison group. Androphilic men and fa'afafine reported greater sexual attraction to men than women and viewed the images of men longer than those of women. Gynephilic men showed the inverse pattern. Viewing time discrepancies between participant's preferred gender and their non-preferred gender were greater for gynephilic men compared to the two androphilic groups. The implications of these preliminary findings for the use of viewing time measures of male sexual orientation across different cultural contexts are discussed.

The role of mating context and fecundability in women's preferences for men's facial masculinity and beardedness.

The ovulatory shift hypothesis proposes that women's preferences for masculine physical and behavioral traits are greater at the peri-ovulatory period than at other points of the menstrual cycle. However, many previous studies used self-reported menstrual cycle data to estimate fecundability rather than confirming the peri-ovulatory phase hormonally. Here we report two studies and three analyses revisiting the ovulatory shift hypothesis with respect to both facial masculinity and beardedness. In Study 1, a large sample of female participants (N = 2,161) self-reported their cycle phase and provided ratings for faces varying in beardedness (clean-shaven, light stubble, heavy stubble, full beards) and masculinity (-50%, -25%, natural, +25% and +50%) in a between-subjects design. In Study 2, 68 women provided the same ratings data, in a within-subjects design in which fertility was confirmed via luteinising hormone (LH) tests and analysed categorically. In Study 2, we also measured salivary estradiol (E) and progesterone (P) at the low and high fertility phases of the menstrual cycle among 36 of these women and tested whether shifts in E, P or E:P ratios predicted face preferences. Preferences for facial masculinity and beardedness did not vary as predicted with fecundability in Study 1, or with respect to fertility as confirmed via LH in Study 2. However, consistent with the ovulatory shift hypothesis, increasing E (associated with cyclical increases in fecundability) predicted increases in preferences for relatively more masculine faces; while high P (associated with cyclical decreases in fecundability) predicted increases in preferences for relatively more feminine faces. We also found an interaction between E and preferences for facial masculinity and beardedness, such that stubble was more attractive on un-manipulated than more masculine faces among women with high E. We consider discrepancies between our findings and those of other recent studies and suggest that closer scrutiny of the stimuli used to measure masculinity preferences across studies may help account for the many conflicting findings that have recently appeared regarding cycle phase preference shifts for facial masculinity.