Contemporary mate preferences can provide important clues to human reproductive history. Little is known about which characteristics people value in potential mates. Five predictions were made about sex differences in human mate preferences based on evolutionary conceptions of parental investment, sexual selection, human reproductive capacity, and sexual asymmetries regarding certainty of paternity versus maternity. The predictions centered on how each sex valued earning capacity, ambition— industriousness, youth, physical attractiveness, and chastity. Predictions were tested in data from 37 samples drawn from (...) 33 countries located on six continents and five islands. For 27 countries, demographic data on actual age at marriage provided a validity check on questionnaire data. Females were found to value cues toresource acquisitionin potential mates more highly than males. Characteristics signalingreproductive capacitywere valued more by males than by females. These sex differences may reflect different evolutionary selection pressures on human males and females; they provide powerful cross-cultural evidence of current sex differences in reproductive strategies. Discussion focuses on proximate mechanisms underlying mate preferences, consequences for human intrasexual competition, and the limitations of this study. (shrink)

Dual functional brain asymmetry refers to the notion that in most individuals the left cerebral hemisphere is specialized for language functions, whereas the right cerebral hemisphere is more important than the left for the perception, construction, and recall of stimuli that are difficult to verbalize. In the last twenty years there have been scattered reports of sex differences in degree of hemispheric specialization. This review provides a critical framework within which two related topics are discussed: Do meaningful sex differences in (...) verbal or spatial cerebral lateralization exist? and, if so, Is the brain of one sex more symmetrically organized than the other? Data gathered on right-handed adults are examined from clinical studies of patients with unilateral brain lesions; from dichotic listening, tachistoscopic, and sensorimotor studies of functional asymmetries in non-brain-damaged subjects; from anatomical and electrophysiological investigations, as well as from the developmental literature. Retrospective and descriptive findings predominate over prospective and experimental methodologies. Nevertheless, there is an impressive accummulation of evidence suggesting that the male brain may be more asymmetrically organized than the female brain, both for verbal and nonverbal functions. These trends are rarely found in childhood but are often significant in the mature organism. (shrink)

Several hundred thousand intellectually talented 12-to 13-year-olds have been tested nationwide over the past 16 years with the mathematics and verbal sections of the Scholastic Aptitude Test (SAT). Although no sex differences in verbal ability have been found, there have been consistent sex differences favoring males in mathematical reasoning ability, as measured by the mathematics section of the SAT (SAT-M). These differences are most pronounced at the highest levels of mathematical reasoning, they are stable over time, and they are observed (...) in other countries as well. The sex difference in mathematical reasoning ability can predict subsequent sex differences in achievement in mathematics and science and is therefore of practical importance. To date a primarily environmental explanation for the difference in ability has not received support from the numerous studies conducted over many years by the staff of Study of Mathematically Precocious Youth (SMPY) and others. We have studied some of the classical environmental hypotheses: attitudes toward mathematics, perceived usefulness of mathematics, confidence, expectations/ encouragement from parents and others, sex-typing, and differential course-taking. In addition, several physiological correlates of extremely high mathematical reasoning ability have been identified (left-handedness, allergies, myopia, and perhaps bilateral representation of cognitive functions and prenatal hormonal exposure). It is therefore proposed that the sex difference in SAT-M scores among intellectually talented students, which may be related to greater male variability, results from both environmental and biological factors. (shrink)

The present study aimed to quantify the magnitude of sex differences in humans' ability to accurately recognise non-verbal emotional displays. Studies of relevance were those that required explicit labelling of discrete emotions presented in the visual and/or auditory modality. A final set of 551 effect sizes from 215 samples was included in a multilevel meta-analysis. The results showed a small overall advantage in favour of females on emotion recognition tasks (d = 0.19). However, the magnitude of that sex difference (...) was moderated by several factors, namely specific emotion, emotion type (negative, positive), sex of the actor, sensory modality (visual, audio, audio-visual) and age of the participants. Method of presentation (computer, slides, print, etc.), type of measurement (response time, accuracy) and year of publication did not significantly contribute to variance in effect sizes. These findings are discussed in the context of social and biological explanations of sex differences in emotion recognition. (shrink)

This study investigated sex differences in interest in infants among children, adolescents, young adults, and older individuals. Interest in infants was assessed with responses to images depicting animal and human infants versus adults, and with verbal responses to questionnaires. Clear sex differences, irrespective of age, emerged in all visual and verbal tests, with females being more interested in infants than males. Male interest in infants remained fairly stable across the four age groups, whereas female interest in infants was highest in (...) childhood and adolescence and declined thereafter, particularly for the responses to visual stimuli. The observed developmental changes in female interest in infants are consistent with the hypothesis that they represent a biological adaptation for parenting. (shrink)

A mime presented on videotape Adler’s six great ideas of truth, goodness, beauty, liberty, equality, and justice; their opposites; and the transitions from the positive or “good” concepts to their opposites. Using Johansson’s (1973) technique, the performer’s 12 joints were marked with points of light. Overall, the viewers had marginal success in identifying the concepts, but females were much more successful than males in identifying the “bad” ones of evil, slavery, falsehood, and ugliness, averaging 62% correct to the males’ 23%. (...) The results agree with Hall’s (1984) discussion of sex differences in the interpretation of nonverbal behavior. (shrink)

I ask three questions related to the claims made within the staying alive theory : Is survival more fitness-enhancing for females than for males? Does the historical record on sex differences in mortality support the SAT? Is it possible to talk about “independent selective pressures on both male and female traits” when all we have are sex/gender comparisons?

Although moral psychologists and feminist moral theorists emphasize males’ interest in justice or fairness and females’ interest in care or empathy, recent work in evolutionary psychology links females’ interests in care and empathy for others with interests in fairness and equality. In an important work on sex differences in cognitive abilities, David Geary (1998) argues that the evolutionary mechanism of sexual selection drives the evolution of particular cognitive abilities and selection for particular interests. I mount two main challenges to Geary’s (...) claims. First, I argue that female social and intrasexual competitive environments evolve, which challenges the assumption that such environments are largely nonkin-based and characterized by reciprocity. Second, I grant Geary’s entire characterization of female environments, but argue that the natures of reciprocal relationships themselves do not require and may not select for interests in fairness and equality. This analysis not only challenges claims regarding sex differences in moral interests, but also suggests the need for a diachronic model of male and female social and intrasexual competitive environments. In addition, I propose a return to Trivers’s (1971) focus on the suite of emotions underlying reciprocal altruism as properties and features of individuals as fodder for selection. (shrink)

Venturing into novel terrain poses physical risks to a female and her offspring. Females have a greater tendency to avoid physical harm, while males tend to have larger range sizes and often outperform females in navigation-related tasks. Given this backdrop, we expected that females would explore a novel environment with more caution than males, and that more-cautious exploration would negatively affect navigation performance. Participants explored a novel, large-scale, virtual environment in search of five objects, pointed in the direction of each (...) object from the origin, and then navigated back to the objects. We found that females demonstrated more caution while exploring as reflected in the increased amounts of pausing and revisiting of previously traversed locations. In addition, more pausing and revisiting behaviors led to degradation in navigation performance. Finally, individual levels of trait harm avoidance were positively associated with the amount of revisiting behavior during exploration. These findings support the idea that the fitness costs associated with long-distance travel may encourage females to take a more cautious approach to spatial exploration, and that this caution may partially explain the sex differences in navigation performance. (shrink)

Women have consistently higher levels of disgust than men. This sex difference is substantial in magnitude, highly replicable, emerges with diverse assessment methods, and affects a wide array of outcomes—including job selection, mate choice, food aversions, and psychological disorders. Despite the importance of this far-reaching sex difference, sound theoretical explanations have lagged behind the empirical discoveries. In this article, we focus on the evolutionary-functional level of analysis, outlining hypotheses capable of explaining why women have higher levels of disgust (...) than men. We present four hypotheses for sexual disgust and six for pathogen disgust, along with testable predictions. Discussion focuses on additional new hypotheses and on future research capable of adjudicating among these competing, but not mutually exclusive, hypotheses. (shrink)

This article considers 3 claims that cognitive sex differ- ences account for the differential representation of men and women in high-level careers in mathematics and sci- ence: (a) males are more focused on objects from the beginning of life and therefore are predisposed to better learning about mechanical systems; (b) males have a pro- file of spatial and numerical abilities producing greater aptitude for mathematics; and (c) males are more variable in their cognitive abilities and therefore predominate at the upper (...) reaches of mathematical talent. Research on cogni- tive development in human infants, preschool children, and students at all levels fails to support these claims. Instead, it provides evidence that mathematical and scientific rea- soning develop from a set of biologically based cognitive capacities that males and females share. These capacities lead men and women to develop equal talent for mathe- matics and science. (shrink)

Previous meta-analyses support a female advantage in decoding non-verbal emotion (Hall, 1978, 1984), yet the mechanisms underlying this advantage are not understood. The present study examined whether the female advantage is related to greater female attention to the eyes. Eye-tracking techniques were used to measure attention to the eyes in 19 males and 20 females during a facial expression recognition task. Women were faster and more accurate in their expression recognition compared with men, and women looked more at the eyes (...) than men. Positive relationships were observed between dwell time and number of fixations to the eyes and both accuracy of facial expression recognition and speed of facial expression recognition. These results support the hypothesis that the female advantage in facial expression recognition is related to greater female attention to the eyes. (shrink)

Are there sex differences in pain? For experimentally delivered somatic stimuli, females have lower thresholds, greater ability to discriminate, higher pain ratings, and less tolerance of noxious stimuli than males. These differences, however, are small, exist only for certain forms of stimulation and are affected by many situational variables such as presence of disease, experimental setting, and even nutritive status. For endogenous pains, women report more multiple pains in more body regions than men. With no obvious underlying rationale, some painful (...) diseases are more prevalent among females, others among males and, for many diseases, symptoms differ between females and males. Sex differences in attitudes exist that affect not only reporting, coping, and responses to treatment, but also measurement and treatment. So many variables are operative, however, that the most striking feature of sex differences in reported pain experience is the apparent overall lack of them. On the other hand, deduction from known biological sex differences suggests that these are powerful sex differences in the operation of pain mechanisms. First, the vaginal canal provides an additional route in women for internal trauma and invasion by pathological agents that puts them at greater risk for developing hyperalgesia in multiple body regions. Second, sex differences in temporal patterns are likely to give rise to sex differences in how pain is and stimuli are interpreted, a situation that could lead to a greater variability and wider range of pains without obvious peripheral pathology among females. Third, sex differences in the actions of sex hormones suggest pain-relevant differences in the operation of many neuroactive agents, opiate and nonopiate systems, nerve growth factor, and the sympathetic system. Thus, while inductive analysis of existing data demonstrate more similarities than differences in pain experience between females and males, deductive analysis suggests important operational sex differences in its production. (shrink)

Sex‐specific transcriptional and epigenomic profiles are detectable in the embryo very soon after fertilization. I propose that in male (XY) and female (XX) pre‐implantation embryos sex chromosomes establish sexually dimorphic interactions with the autosomes, before overt differences become apparent and long before gonadogenesis. Lineage determination restricts expression biases between the sexes, but the epigenetic differences are less constrained and can be perpetuated, accounting for dimorphisms that arise later in life. In this way, sexual identity is registered in the epigenome very (...) early in development. As development progresses, sex‐specific regulatory modules are harbored within shared transcriptional networks that delineate common traits. In reviewing this field, I propose that analyzing the mechanisms for sexual dimorphisms at the molecular and biochemical level and incorporating developmental and environmental factors will lead to a greater understanding of sex differences in health and disease. (shrink)

The standard view about sex differences in sexual desire is that males are lusty and loose, while females are cool and coy. This is widely believed and is a core premise of some scientific programs like evolutionary psychology. But is it true? A mountain of evidence seems to support the standard view. Yet, this evidence is shot through with methodological and philosophical problems. Developments in the study of sexual desire suggest that some of these problems can be resolved, and when (...) they are, the standard view looks, at best, to be an exaggeration. (shrink)

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%). (shrink)

The learning of immediate causation within a dynamic environment was examined. Participants encountered seven decision points in which they needed to choose which of three possible candidates was the cause of explosions in the environment. Each candidate was firing a weapon at random every few seconds, but only one of them produced an immediate effect. Some participants showed little learning, but most demonstrated increases in accuracy across time. On average, men showed higher accuracy and shorter latencies that were not explained (...) by differences in self-reported prior video game experience. This result suggests that prior reports of sex differences in causal choice in the game are not specific to situations involving delayed or probabilistic causal relations. (shrink)

Adequate measurement is an essential component of the assessment of mental health disorders and symptoms such as depression and anxiety. The present study investigated sex-specific differences in the Patient Health Questionnaire-9 and Generalized Anxiety Disorder-7. This comprehensive cross-sectional design study pursued four objectives: measurement invariance of PHQ-9 and GAD-7 between male and female; depression and anxiety prevalence differences; cross-sex differences in the relationship between depression and anxiety; and a comparison of symptom heterogeneity. A sample of 1966 students from South Africa (...) completed the PHQ-9 and the GAD-7. Data analyses for measurement invariance, latent class analysis, inter-variable correlations and group comparisons were conducted in Mplus. The two-dimensional PHQ-9 achieved scalar invariance, while the GAD-7 yielded metric invariance. The somatic and non-somatic latent dimensions of depression were compared and showed no significant difference between male and female groups. The positive relationship between depression and anxiety was also not significantly different between the two groups. While the PHQ-9 symptoms formed three classes in the male group, and four classes in the female group, the GAD-7 had the same number of classes and a similar pattern between the two groups. These findings hold implications for the measurement, assessment and understanding of symptom manifestation and distribution, as well as the treatment of depression and anxiety in South Africa. (shrink)

Schmitt's findings provide little evidence that sex differences in sociosexuality are explained by evolved dispositions. These sex differences are better explained by an evolutionary account that treats the psychological attributes of women and men as emergent, given the biological attributes of the sexes, especially female reproductive capacity, and the economic and social structural aspects of societies.

Although the majority of literature has shown undistinguishable attentional effects when eye-gaze and arrows are used as cues, recent research has found that whereas eye-gaze selectively orient attention to the specific location or part of the object looked at, arrows unselectively direct attention towards parts of the environment. However, it is unclear whether this dissociation between gaze and arrow cues is related to social cognitive mechanisms such as the attribution of mental states (Theory of Mind, ToM). We aimed at replicating (...) the dissociation between gaze and arrow cues and investigating sex differences in attentional object selection triggered by these two types of stimuli. While we replicated the arrow-gaze dissociation, this was equivalent in the male and female population. This finding seems to run counter the intuition that theory of mind abilities can account for the dissociation observed between gaze and arrow cues since greater ToM abilities have been generally shown in females. However, this conclusion it must be interpreted with caution since no differences in ToM abilities and autistic quotient scores were observed between male and female in our sample. Further research is needed to shed light on this issue. (shrink)

The finding that women are attracted to men older than themselves whereas men are attracted to relatively younger women has been explained by social psychologists in terms of economic exchange rooted in traditional sex-role norms. An alternative evolutionary model suggests that males and females follow different reproductive strategies, and predicts a more complex relationship between gender and age preferences. In particular, males' preferences for relatively younger females should be minimal during early mating years, but should become more pronounced as the (...) male gets older. Young females are expected to prefer somewhat older males during their early years and to change less as they age. We briefly review relevant theory and present results of six studies testing this prediction. Study 1 finds support for this gender-differentiated prediction in age preferences expressed in personal advertisements. Study 2 supports the prediction with marriage statistics from two U.S. cities. Study 3 examines the cross-generational robustness of the phenomenon, and finds the same pattern in marriage statistics from 1923. Study 4 replicates Study 1 using matrimonial advertisements from two European countries, and from India. Study 5 finds a consistent pattern in marriages recorded from 1913 through 1939 on a small island in the Philippines. Study 6 reveals the same pattern in singles advertisements placed by financially successful American women and men. We consider the limitations of previous normative and evolutionary explanations of age preferences and discuss the advantages of expanding previous models to include the life history perspective. (shrink)

ABSTRACTPerception of emotion in the face is a key component of human social cognition and is considered vital for many domains of life; however, little is known about how this ability differs across the lifespan for men and women. We addressed this question with a large community sample of persons ranging from younger than 15 to older than 60 years of age. Participants were viewers of the television show “Tout le Monde Joue”, and the task was presented on television, with (...) participants responding via their mobile devices. Applying latent variable modeling, and establishing measurement invariance between males and females and across age, we found that, for both males and females, emotion perception abilities peak between the ages of 15 and 30, with poorer performance by younger adults and declining performance after the age of 30. In addition, we show a consistent advantage by females across the lifespan, which decreases in magnitude with increasing age. This large scale study with a wide ran... (shrink)

The argument of berkley for the existence sex differences in pain is based on biological factors. We suggest that the psychological evidence for such differences is more substantial.

Geary proposes a sociobiological hypothesis of how sex differences in math and spatial skills might have jointly arisen. His distinction between primary and secondary math skills is noteworthy, and in some ways analogous to the closed versus open systems postulated to exist for language. In this commentary issues concerning how genes might affect complex cognitive skills, the interpretation of heritability estimates, and prior research abilites are discussed.

Sex differences in aggressive and risk-taking behaviors have practical implications for sexual integration of military combat units. The social-role theory implies that female soldiers will adapt to their role and display the same aggressive and risk-taking propensities as their male comrades. If sex differences reflect evolved propensities, however, adoption of the soldier's role is unlikely to eliminate those differences.

The COVID-19 pandemic has caused a global societal, economic, and social upheaval unseen in living memory. There have been substantial cross-national differences in the kinds of policies implemented by political decision-makers to prevent the spread of the virus, to test the population, and to manage infected patients. Among other factors, these policies vary with politicians’ sex: early findings indicate that, on average, female leaders seem more focused on minimizing direct human suffering caused by the SARS-CoV-2 virus, while male leaders implement (...) riskier short-term decisions, possibly aiming to minimize economic disruptions. These sex differences are consistent with broader findings in psychology, reflecting women’s stronger empathy, higher pathogen disgust, health concern, care-taking orientation, and dislike for the suffering of other people—as well as men’s higher risk-taking, Machiavellianism, psychopathy, narcissism, and focus on financial indicators of success and status. This review article contextualizes sex differences in pandemic leadership in an evolutionary framework. Evolution by natural selection is the only known process in nature that organizes organisms into higher degrees of functional order, or counteracts the unavoidable disorder that would otherwise ensue, and is therefore essential for explaining the origins of human sex differences. Differential sexual selection and parental investment between males and females, together with the sexual differentiation of the mammalian brain, drive sex differences in cognition and behavioral dispositions, underlying men’s and women’s leadership styles and decision-making during a global pandemic. According to thesexually dimorphic leadership specialization hypothesis, general psychobehavioral sex differences have been exapted during human evolution to create sexually dimorphic leadership styles. They may be facultatively co-opted by societies and/or followers when facing different kinds of ecological and/or sociopolitical threats, such as disease outbreaks or intergroup aggression. Early evidence indicates that against the invisible viral foe that can bring nations to their knees, the strategic circumspection of empathic feminine health “worriers” may bring more effective and humanitarian outcomes than the devil-may-care incaution of masculine risk-taking “warriors”. (shrink)

From the perspective of evolutionary theory, we believe it makes more sense to view the sex differences in spatial cognition as being an evolutionary by-product of selection for optimal rates of fetal development. Geary does not convince us that his proposed selective factors operated with “sufficient precision, economy, and efficiency.” Moreover, the archaeological evidence does not support his proposed evolutionary scenario.

Discussions in neuroethics to date have ignored an ever-increasing neuroscientific lilterature on sex differences in brains. If, indeed, there are significant differences in the brains of men versus women and in the brains of boys versus girls, the ethical and social implications loom very large. I argue that recent neuroscientific findings on sex-based brain differences have significant implications for theories of morality and for our understandings of the neuroscience of moral cognition and behavior.

BackgroundBoth impairment and sex differences in social cognition and neurocognition have been documented in schizophrenia. However, whether sex differences exist in the association between social cognition and neurocognition are not known. We aimed to investigate the contribution of areas of neurocognition to theory of mind and hostility bias, representing social cognition, according to sex in early course schizophrenia.MethodsIn this cross-sectional study, we assessed neurocognition using the Japanese version of the Brief Assessment of Cognition in Schizophrenia and assessed the ToM and (...) hostility bias subdomains of social cognition using the Social Cognition Screening Questionnaire in 131 participants diagnosed with schizophrenia within 5 years of onset. Sex differences were analyzed using t-tests. The associations of neurocognitive subdomains with ToM and hostility bias according to sex were analyzed using multiple regression analysis. Results were adjusted by age, estimated premorbid intelligence quotient, and symptomatology.ResultsNo sex differences were found in ToM or hostility bias. Higher verbal fluency was significantly associated with higher ToM in females, whereas higher executive function was significantly associated with higher ToM in males. Higher verbal fluency was significantly associated with lower hostility bias in females, whereas neurocognition and hostility bias were not significantly associated in males.ConclusionThe results suggest that neurocognition associated with social cognition differ according to sex. These differences should be considered for more effective treatment of social cognition. (shrink)

It is hypothesized from within an evolutionary framework that females should be less invested in peer relations than males. Investment was operationalized as enjoyment in Study 1 and as preference for interaction in Study 2. In the first study, four- and six-year-old children’s enjoyment of peer interaction was observed in 26 groups of same-sex peers. Girls were rated as enjoying their interactions significantly less than boys. In the second study, six- and nine-year-old children were interviewed about the individuals with whom (...) they spend time in their homes and neighborhoods and about the individuals who participate in their favorite activities. The proportion of individuals named by children who were peers was significantly lower for girls than boys both in children’s neighborhoods and in children’s favorite activities. Results strongly support the hypothesis that females and males have evolved differential preferences for interaction with peers. (shrink)

Mower questions some aspects of Geary's proposals regarding the nature of male-male and female-female relationships during human evolution and the implications for understanding the basis for same-sex friendships. The core of this proposal is reviewed and Mower's challenges to the core are addressed.