Despite a staggering body of research demonstrating sex differences in expressed emotion, very few theoretical models (evolutionary or non-evolutionary) offer a critical examination of the adaptive nature of such differences. From the perspective of a socio-relational framework, emotive behaviors evolved to promote the attraction and aversion of different types of relationships by advertising the two most parsimonious properties of reciprocity potential, or perceived attractiveness as a prospective social partner. These are the individual's (a) perceived capacity or ability to (...) provide expedient resources, or to inflict immediate harm onto others, and their (b) perceived trustworthiness or probability of actually reciprocating altruism (Vigil 2007). Depending on the unique social demands and relational constraints that each sex evolved, individuals should be sensitive to advertise and cues through selective displays of dominant versus submissive and masculine versus feminine emotive behaviors, respectively. In this article, I introduce the basic theoretical assumptions and hypotheses of the framework, and show how the models provide a solid scaffold with which to begin to interpret common sex differences in the emotional development literature. I conclude by describing how the framework can be used to predict condition-based and situation-based variation in affect and other forms of expressive behaviors. (shrink)
I argue that the magnitude and nature of sex differences in aggression, their development, causation, and variability, can be better explained by sexual selection than by the alternative biosocial version of social role theory. Thus, sex differences in physical aggression increase with the degree of risk, occur early in life, peak in young adulthood, and are likely to be mediated by greater male impulsiveness, and greater female fear of physical danger. Male variability in physical aggression is consistent with (...) an alternative life history perspective, and context-dependent variability with responses to reproductive competition, although some variability follows the internal and external influences of social roles. Other sex differences, in variance in reproductive output, threat displays, size and strength, maturation rates, and mortality and conception rates, all indicate that male aggression is part of a sexually selected adaptive complex. Physical aggression between partners can be explained using different evolutionary principles, arising from the conflicts of interest between males and females entering a reproductive alliance, combined with variability following differences in societal gender roles. In this case, social roles are particularly important since they enable both the relatively equality in physical aggression between partners from Western nations, and the considerable cross-national variability, to be explained. (shrink)
Sex differences in mortality rates stem from genetic, physiological, behavioral, and social causes that are best understood when integrated in an evolutionary life history framework. This paper investigates the Male-to-Female Mortality Ratio (M:F MR) from external and internal causes and across contexts to illustrate how sex differences shaped by sexual selection interact with the environment to yield a pattern with some consistency, but also with expected variations due to socioeconomic and other factors.
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)
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)
Previous research suggests that individuals diagnosed with morbid jealousy have jealousy mechanisms that are activated at lower thresholds than individuals with normal jealousy, but that these mechanisms produce behavior that is similar to individuals with normal jealousy. We extended previous research documenting these similarities by investigating sex differences in partner-directed violence committed by individuals diagnosed with morbid jealousy. The results support some of our predictions. For example, a greater percentage of men than women diagnosed with morbid jealousy used physical (...) violence, attempted to kill, and actually killed their partners, and used their hands rather than an object to kill their partners. These results replicate results generated for individuals with normal jealousy. Discussion addresses implications of the current research and highlights directions for future research on the psychology of morbid jealousy. (shrink)
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)
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)
For nearly 70 years, studies have shown large sex differences in human mate selection preferences. However, most of the studies were restricted to a limited set of mate selection criteria and to college students, and neglecting relationship status. In this study, 21,245 heterosexual participants between 18 and 65 years of age (mean age 41) who at the time were not involved in a close relationship rated the importance of 82 mate selection criteria adapted from previous studies, reported age ranges (...) for the oldest and youngest partner that they would find acceptable, and responded to 10 yes/no questions about a potential marriage partner. For nearly all mate selection criteria, women were found to be the more demanding sex, although men placed consistently more value on the physical attractiveness of a potential partner than women. Also, the effects of the participants’ age and level of education were nearly negligible. These results demonstrate the robustness of sex differences in mate selection criteria across a substantial age range. (shrink)
In this article, we argue that there is an essential difference between social intelligence and creative intelligence, and that they have their foundation in human sexuality. For sex differences, we refer to the vast psychological, neurological, and cognitive science research where problem-solving, verbal skills, logical reasoning, and other topics are dealt with. Intelligence tests suggest that, on average, neither sex has more general intelligence than the other. Though people are equals in general intelligence, they are different in special forms (...) of intelligence such as social intelligence and creative intelligence, the former dominant in women, the latter dominant in men. The dominance of creative intelligence in men needs to be explained. The focus of our research is on the strictly anthropological aspects, and consequently our explanation for this fact is based on the male-female polarity in the mating systems. Sexual dimorphism does not only regard bodily differences but implies different forms of sex life. Sex researchers distinguish between two levels of sexual intercourse: procreative sex and recreational sex, and to these we would add “creative sex.” On all three levels, there is a behavioral difference between men and women, including the subjective experience. These differences are as well attributed to culture as genetically founded in nature. Sexual reproduction is only possible if females cooperate. Their biological inheritance makes females play a decisive role in mate choice. Recreational sex for the purpose of pleasure rather than reproduction results from female extended sexual activity. Creative sex, on the contrary, is a specifically male performance of sexuality. We identify creative sex with eroticism. Eroticism evolved through the transformation of the sexual drive into a mental state of expectation and fantasizing. Hence, sex differences (that nowadays are covered up by cultural egalitarianism) continue to be the evolutionary origin of the difference between social and creative intelligence. (shrink)
The neuroscientific investigation of sex differences has an unsavoury past, in which scientific claims reinforced and legitimated gender roles in ways that were not scientifically justified. Feminist critics have recently argued that the current use of functional neuroimaging technology in sex differences research largely follows that tradition. These charges of ‘neurosexism’ have been countered with arguments that the research being done is informative and valuable and that an over-emphasis on the perils, rather than the promise, of such research (...) threatens to hinder scientific progress. To investigate the validity of these contrasting concerns, recent functional magnetic resonance imaging (fMRI) investigations of sex differences and citation practices were systematically examined. In line with the notion of neurosexism, the research was found to support the influence of false-positive claims of sex differences in the brain, to enable the proliferation of untested, stereotype-consistent functional interpretations, and to pay insufficient attention to the potential plasticity of sex differences in both brain and mind. This, it is argued, creates a literature biased toward the presentation of sex differences in the brain as extensive, functionally significant, and fixed—and therefore implicitly supportive of a gender essentialist perspective. It is suggested that taking feminist criticisms into account would bring about substantial improvement in the quality of the science, as well as a reduction in socially harmful consequences. (shrink)
Neuroscience research examining sex/gender differences aims to explain behavioral differences between men and women in terms of differences in their brains. Historically, this research has used ad hoc methods and has been conducted explicitly in order to show that prevailing gender roles were dictated by biology. I examine contemporary fMRI research on sex/gender differences in emotion processing and argue that it, too, both uses problematic methods and, in doing so, reinforces gender stereotypes.
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)
In this article I flesh out support for observations that scientific accounts of social groups can influence the very groups and mental phenomena under investigation. The controversial hypothesis that there are hardwired differences between the brains of males and females that contribute to sex differences in gender-typed behaviour is common in both the scientific and popular media. Here I present evidence that such claims, quite independently of their scientific validity, have scope to sustain the very sex differences (...) they seek to explain. I argue that, while further research is required, such claims can have self-fulfilling effects via their influence on social perception, behaviour and attitudes. The real effects of the products of scientists’ research on our minds and society, together with the fact that all scientific hypotheses are subject to dispute and disconfirmation, point to a need for scientists to consider the ethical implications of their work. (shrink)
A self-report questionnaire about involvement in different types of bullying, what behaviours were regarded as bullying, and attitudes towards bullying, bullies and victims was completed by pupils in Year 7 (aged 11/12) through to Year 10 (aged 14/15) ( n = 170). Overall, direct verbal assault was the most commonly reported, and stealing the least frequently reported, type of bullying. For six specific types of bullying investigated, and for a composite measure of all types of bullying, significantly fewer Year 9 (...) pupils than pupils in the other three years reported that they had behaved in these ways in the previous week. No significant sex differences emerged on these measures. These findings suggest that general patterns in bullying activities as a function of age and sex obtained in previous studies do not always hold. Although most pupils indicated that they thought that six out of eight types of behaviour viewed as bullying by researchers should be regarded as bullying, a substantial minority did not. The present study also extended bullying research by examining associations between pupils' definitions and attitudes towards bullying and their reports of bullying others. For one specific type of bullying, 'Forcing people to do things that they don't want to do', significantly fewer pupils who reported that they had behaved in this way than who reported that they had not done so included it in their definition of bullying. A consistent pattern of significant negative correlations of moderate size between attitudes and self-reported involvement in specific types of bullying were obtained. The implications of these findings for those concerned with tackling bullying in schools were discussed. (shrink)
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.
We used 7,415 advertisements published in Spain to analyze traits sought/offered by men and women from different age groups. Findings regarding age, socioeconomic status, and physical attractiveness requirements support evolutionary predictions about mate preferences. However, changes in trait preferences among women under 40 appear to be contingent on Spain’s socioeconomic transformation. Women under 40 seek mainly physical attractiveness in men, whereas those over 40 seek mainly socioeconomic status. The trait most sought by men in all age groups is physical attractiveness. (...) Traits sought and offered by advertisers may be conditioned by the personal situation of the advertiser. Mean age of advertisers (around their forties) and Spain’s social indicators suggest that the majority of advertisers have been unsuccessful in the mating arena at the conventional age. (shrink)
Research demonstrates that women experience disgust more readily and with more intensity than men. The experience of disgust is associated with increased attention to disgust-related stimuli, but no prior study has examined sex differences in attention to disgust facial expressions. We hypothesised that women, compared to men, would demonstrate increased attention to disgust facial expressions. Participants completed an eye tracking task to measure visual attention to emotional facial expressions. Results indicated that women spent more time attending to disgust facial (...) expressions compared to men. Unexpectedly, we found that men spent significantly more time attending to neutral faces compared to women. The findings indicate that women’s increased experience of emotional disgust also extends to attention to disgust facial stimuli. These findings may help to explain sex differences in the experience of disgust and in diagnoses of anxiety disorders in which disgust plays an important role. (shrink)
The relation between testosterone levels and aggressive behavior is well established. From an evolutionary viewpoint, testosterone can explain at least part of the sex differences found in aggressive behavior. This explanation, however, is mediated by factors such as prenatal testosterone levels and basal levels of cortisol. Especially regarding sex differences in aggression during adolescence, these mediators have great influence. Based on developmental brain structure research we argue that sex differences in aggression have a pre-pubertal origin and are (...) maintained during adolescence. Evidence of prenatal, adolescent, and adult levels of testosterone in relation to aggression taken together, support Archer's argument for sexual selection as the driver of sex differences in aggression. (shrink)
In this commentary, we review evidence that production-based (perceiver-independent) measures reveal few consistent sex differences in emotion. Further, sex differences in perceiver-based measures can be attributed to retrospective or dispositional biases. We end by discussing an alternative view that women might appear to be more emotional because they are more facile with emotion language.
Vigil's socio-relational framework of sex differences in emotional expressiveness emphasizes general sex differences in emotional responding, but largely ignores the social context in which emotions are expressed. There is much empirical evidence showing that sex differences in emotion displays are flexible and a function of specific social roles and demands, rather than a reflection of evolutionary-based social adjustments.
Gangestad & Simpson make a major contribution by highlighting the importance of mate choice for good genes, the costs of alternative strategies, and tradeoffs inherent in human mating. By downplaying sex differences and ignoring the nongenetic adaptive benefits of short term mating, however, they undermine their goal of “strategic pluralism” by presenting a theory devoid of many documented complexities of human mating.
According to I3 Theory, individuals enact aggressive behaviors when (a) instigating triggers are severe, (b) impelling forces are strong, and/or (c) inhibiting forces are weak. Archer's analysis of human sex differences in aggression could be bolstered by a careful analysis of male-female discrepancies in reactivity (or exposure) to instigating triggers, proneness toward impelling forces, and/or proneness toward inhibiting forces.
Sexual selection traditionally involves male-male competition and female choice, but in some species, including humans, sexual selection can also involve female-female competition and male choice. The degree to which one aspect of sexual selection or another is manifest in human populations will be influenced by a host of social and ecological variables, including the operational sex ratio. These variables are discussed in connection with the relative contribution of sexual selection and the division of labor to the evolution of human sex (...)differences. (shrink)
An evolutionary psychological perspective drawing on sexual selection theory can better explain sex differences in aggression and violence than can social constructionist theories. Moreover, there is accumulating evidence that, in accordance with predictions derived from sexual selection theory, men modulate their willingness to engage in risky and violent confrontations in response to cues to fitness variance and future prospects.
Human aggression has two important dimensions: within-group aggression and between-group aggression. Archer offers an excellent treatment of the former only. A full explanation of sex differences in aggression will fail without accounting for our history of inter-group aggression, which has deep evolutionary roots and specific psychological adaptations. The causes and consequences of inter-group aggression are dramatically different for males and females.
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.
At the heart of the debate between social role theorists and evolutionary psychologists is whether natural selection has designed the minds of the sexes differently to some interesting extent. In this commentary I describe the standards of evidence for both the positive and negative claims. In my opinion, Archer has met the standard for designed sex differences in intrasexual conflict.
Among hunter-gatherers, the sharing of male and female foods is often assumed to result in virtually the same diet for males and females. Although food sharing is widespread among the hunting and gathering Hadza of Tanzania, women were observed eating significantly more tubers than men. This study investigates the relationship between patterns of dental wear, diet, and extramasticatory use of teeth among the Hadza. Casts of the upper dentitions were made from molds taken from 126 adults and scored according to (...) the Murphy dental attrition scoring system. Females had significantly greater anterior occlusal wear than males when we controlled for age. Males exhibited greater asymmetry in wear, with greater wear on the left side in canines, first premolars, and first molars. We suggest that these sex differences in wear patterns reflect the differences seen in the diet, as well as in the use of teeth as tools. (shrink)
The ultimate causes of sex differences in human aggressive behavior can lie mainly in evolved, inherited mechanisms that differ by sex or mainly in the differing placement of women and men in the social structure. The present commentary contrasts Campbell's evolutionary interpretation of aggression sex differences with a social structural interpretation that encompasses a wider range of phenomena.
We agree with Archer that human sex differences in aggression are well explained by sexual selection, but note that explanations of human behaviors are not logically mutually exclusive from explanations and therefore should not be framed as such. We discuss why this type of framing hinders the development of both social learning and evolutionary theories of human behavior.
Archer recognizes that sexual selection theory is sensitive to the effects of ecologies on sex differences, yet he does not explain the impact of such variation. For example, to what degree are there sex differences in aggression in polygynous and monogamous societies? I demonstrate how differences in mating perceptions affect the traditional dichotomy that males compete for and females choose mates.
As Archer argues, recent developmental data on human physical aggression support the sexual selection hypothesis. However, sex differences are largely due to males on a chronic trajectory of aggression. Maternal characteristics of these males suggest that, in societies with low levels of physical violence, females with a history of behavior problems largely contribute to maintenance of physical aggression sex differences.
Four issues relevant to sex differences in human aggression and violence are considered. (1) The motivation for play and serious aggression in children and juvenile animals is different. Consequently, the evolutionary explanations for each may be different. (2) Sex differences in intrasexual aggression may be due to effects of the attacker or the target. There is evidence that both males and females are more physically aggressive against males and less physically aggressive against females. The evolutionary explanation for each (...) component of the sex difference in intrasexual aggression may be different. (3) Aggression and violence are defined. The former is the attack, and the latter is the consequent injury or death. The evolutionary explanation for each may not be the same. (4) Most men and women are neither physically aggressive nor criminally violent. The evolutionary explanations of sex differences in aggression and violence should take this polymorphism into account. (shrink)
Dream research shows sex differences in dream aggression that fit very well with the findings for waking-life aggressive behaviour. Dream studies are a valuable tool for investigating variables underlying the sex difference in aggression. One might argue that studying dream aggression might be even more promising because aggression in dreams is not socially labelled, as being aggressive in waking life is.