The psychological construct of sociosexuality—one's sexual openness or propensity to engage in uncommitted sexual relationships—has been broadly examined within numerous cultures and mating contexts. Although there is some evidence suggesting that components of sociosexuality, namely behavior, desire and attitude, change within-person, relatively little research has investigated potential sources of

Like psychology more broadly, developmental psychology has long suffered from a narrow focus on children from WEIRD societies—or those that are Western, Educated, Industrialized, Rich, and Democratic. In this review, we discuss how developmental scientists have sought to correct this bias through two complementary approaches: one centered on detailed, ethnographic investigations of child development

Research in the social sciences has largely relied on Western, Educated, Industrialized, Rich, and Democratic (WEIRD) participants, yet scholars tend to use findings from such WEIRD samples to draw conclusions about human psychology at large. There is, however, one prominent area of psychological science drawing on evolutionary theory that marks a major exception to this trend: research on the nonverbal

Human behavior and collective actions are strongly affected by social institutions. A question of great theoretical and practical importance is how successful social institutions get established and spread across groups and societies. Here, using institutionalized punishment in small-scale societies as an example, we contrast two prominent mechanisms - selective imitation and self-interested design

Why is life paced so differently across as well as within organisms? Can one expect across-species patterns to be repeated within a species too, among individuals? The answer to these questions requires understanding conditions under which reaction norms evolve. We provide an overview of what we believe to be understudied areas of life-history theory, to foster theoretical work and to help deriving

Among non-human animals, a key strategy to resolve conflicts without fighting relies on assessing relative fighting ability on the basis of physical cues such as size and strength. Recent studies hypothesize that the human mind also contains mechanisms for spontaneously coordinating conflict behavior on the basis of difference in physical strength, even if strength is not rationally relevant to the

The evolutionary social sciences (ESSs) are thriving, and seem to have entered a period of normal science. This is a good time to examine our own practices, theoretical and empirical, and to ask how we might improve. Here I review papers published in the past five years in EHB to explore major trends in the field. Theoretically, the popularity of certain topics (cooperation, mating, life history) has

There are two broad functional explanations for second-party punishment: fitness-leveling and deterrence. The former suggests that people punish to reduce fitness differences, while the latter suggests that people punish in order to reciprocate losses and deter others from inflicting losses on them in the future. We explore the relative roles of these motivations using a pre-registered, two-player

Researchers have suggested that more attractive women will show stronger preferences for masculine men because such women are better placed to offset the potential costs of choosing a masculine mate. However, evidence for correlations between measures of women's own attractiveness and preferences for masculine men is mixed. Moreover, the samples used to test this hypothesis are typically relatively

The idea that individual differences in behavior and physiology can be partly understood by linking them to a fast-slow continuum of life history strategies has become popular in the evolutionary behavioral sciences. I refer to this approach as the “fast-slow paradigm” of individual differences. The paradigm has generated a substantial amount of research, but has also come increasingly under scrutiny

During evolution, humans faced the trade-off between preferences for feminine and masculine traits which are presumably connected to parental care, and genetic quality or provisioning abilities, respectively. Recent research has shown that environmental factors influence preferences for femininity/masculinity in potential mates. However, studies mainly focus on women's preferences for isolated cues

Moral elevation is a positive social emotion, which is triggered by observing third parties behaving benevolently, and which in turn triggers a motivation to behave benevolently towards others in general. It has been suggested that this relatively obscure emotion may be the output of a naturally selected cognitive adaptation which functions to help us retain our position in the competition for access

An overall evaluation of potential relationship partners (mate value) is fundamental to numerous key lifetime decisions, but how people integrate the diverse component traits of mate value remains poorly understood. Three within-subjects studies (N = 190) contrast multiple models of mate value trait integration, including both compensatory and non-compensatory decision-making strategies. A weighted

Modern-day environments differ drastically from those in which humans evolved, which likely has important implications for human mating psychology. Particularly notable is the modern advancement of hormonal contraceptives (HCs), which alter the natural hormones of the many women who use them. According to the HC congruency hypothesis, HCs alter sex hormones and brain processes that are linked to numerous

Hundreds of studies demonstrate human cognitive biases that are both inconsistent with “rational” decision-making and puzzlingly patterned. One such bias, the “endowment effect” (also known as “reluctance to trade”), occurs when people instantly value an item they have just acquired at a much higher price than the maximum they would have paid to acquire it. This bias impedes a vast range of real-world

Despite recent rapid advances in medical knowledge that have improved survival, conventional medical science's understanding of human health and disease relies heavily on people of European descent living in contemporary urban industrialized environments. Given that modern conditions in high-income countries differ widely in terms of lifestyle and exposures compared to those experienced by billions

It is commonly asserted that when extrinsic mortality is high, individuals should invest early in reproduction. This intuition thrives in the literature on life-history theory and human behavior, yet it has been criticized repeatedly on the basis of mathematical models. The intuition is indeed wrong; but a recent theoretical criticism has confused the reason why it is wrong, thereby obscuring earlier

Few studies have examined the role of early vs. later environment in the development of life history (LH) strategies, whether age at sexual debut mediates LH development, or whether LH indicators contribute to environmental stress in adulthood. In the current study, we addressed these gaps cross-culturally using data from Jenu Kurubas who live in the rural outskirts of Mysore (n = 133), India, and

Accurately assessing others' reputation, and developing a reputation as a competent, honest, fair individual—a good epistemic and moral reputation—are critical skills. In six online experiments (N = 2811), replicated with English and Japanese participants, we found that one way to improve our epistemic reputation is to display our competence by sharing valuable ideas, especially if we appropriate these

Inter-group competition including warfare is posited to be a key force in human evolution (Alexander, 1990; Choi & Bowles, 2007; Wrangham, 1999). Chagnon's research on the Yanomamö is seminal to understanding warfare in the types of societies characteristic of human evolutionary history. Chagnon's empirical analyses of the hypothesis that competition for status or cultural success is linked to reproduction

Anthropologist Napoleon A. Chagnon was a central figure in the development and foundation of evolutionary approaches to human behavior. We highlight his ethnographic fieldwork, contributions to studies of kinship and marriage, and his foundational role in the development of evolutionary approaches to human behavior. As a holistic anthropologist Chagnon led anthropology toward the integration of cultural

Evolutionary social scientists have argued that impulsive behavior is adaptive in harsh and unpredictable conditions. Is this true? This paper presents a mathematical model that computes the optimal level of impulsivity in environments varying in harshness and unpredictability. We focus on information impulsivity, i.e., choosing to act without gathering or considering information about the consequences

Links between the human facial width-to-height ratio (fWHR) and aggressive behaviours have been debated in recent years. The question of whether fWHR is a cue to dominance could benefit from the study of primate species that are closely related to humans. We therefore built on the broad literature in humans, and recent research in capuchins, macaques and bonobos, and examined associations between fWHR

Feuding was a near-universal phenomenon, and a classic topic of anthropology and sociology. This article focuses on feuding among nobles in early modern Germany. The German noble feud assumed characteristics that differentiated it from vendetta. It developed into a distinct institution in terms of its legal status, methods and social conditions. It presents a puzzle: most feuds punctuated ongoing relationships

In three studies (n = 427), participants wrote and answered questions about autobiographical episodes involving helping behavior from the perspective of the helper vs. the recipient. Both helpers and recipients reported that the benefits of help outweighed the costs (i.e., the help was non-zero-sum). Helpers underestimated the degree to which recipients felt indebted as a result of receiving help.

Evolutionary theories suggest that humans prefer sexual dimorphism in faces because masculinity in men and femininity in women may be an indicator of immune function during development. In particular, the immunocompetence handicap hypothesis proposes that sexual dimorphism indicates good immune function during development because the sex hormones, particularly testosterone in men, required for the

Close friendships are associated with greater happiness and improved health; historically, they would likely have provided beneficial fitness outcomes. Yet each friendship requires one's finite time and resources to develop and maintain. Because people can maintain only so many close relationships, including friendships, at any one time, choosing which prospective friends to pursue and invest in is

We critically review the use of the term “life history theory” in recent publications on evolutionary psychology, focusing on how the idea of a fast-slow continuum is deployed in that literature. We raise four issues: First, concerning plasticity, should we expect the effects of plasticity on the developmental response of a trait to mirror the effects of selection on the mean of that trait? We conclude

Previous studies have found that using software to pitch shift people's voices can boost their perceived attractiveness to opposite-sex adults: men prefer women's voices when pitch-shifted up, and women prefer men's voices when pitch-shifted down. In this study, we sought to determine whether speakers could affect their perceived vocal attractiveness by voluntarily shifting their own voices to reach

Waist-to-hip ratio (WHR) and breast size are considered important biological features defining female body attractiveness; but their neurophysiological correlates remain largely unknown. To shed light on this issue, behavioral and electroencephalographic responses were recorded while healthy heterosexual men and women completed an oddball task, which was then followed by an attractiveness judgement

Why do perceivers categorize and stereotype others by their biological sex and age? We suggest that perceivers do so because sex and age interactively shape adaptive goals (e.g., mating, parenting) and strategies. And because such goals and strategies pose different fitness-relevant opportunities and threats, social perceivers use others' sex-age as a cue for predicting others' behaviors. This perspective

The substantial role of food sharing in human evolution has been widely recognized, and food-soliciting tactics may have been critical in facilitating these transfers. Great apes, our closest living relatives, also use different food-soliciting tactics to obtain food from both kin and non-kin. However, the individual and social factors involved in requests for and subsequent transfers of food have

Pitch is the most perceptually salient feature of the voice, yet it is approximately five standard deviations lower in men than in women, a degree of sexual dimorphism exceeding that of all extant nonhuman apes. Evidence from Western samples suggests that low-frequency vocalizations may have augmented male mating success ancestrally by intimidating competitors and/or attracting mates. However, data

The formation of male-female social bonds and the resulting competition among females for male partners is a core element of human societies. While female competition for a male partner outside the mating context is well studied in humans, evidence from non-human primates is scarce, and its evolutionary roots remain to be explored. We studied two multi male – multi female groups of wild Assamese macaques

Paternal care in humans is facultative, with investment decisions responsive to socioecological context. In particular, paternity confidence is thought to have a significant impact on men's provisioning. However, various aspects of the relationship a man has with his partner can also influence the way he provides for his children. Previous papers have tended to focus either on these kinds of relationship

People often value an item more when they own it than when it is available for purchase, and consequently are relatively reluctant to trade. This is the “endowment effect”, which has been widely documented in human populations and also in some non-human species. This paper develops a simple model in which it is adaptive to have a bias against trade, potentially explaining the basis of the endowment

Accurately assessing others' reputation, and developing a reputation as a competent, honest, fair individual—a good epistemic and moral reputation—are critical skills. One way to gain epistemic reputation is to display our competence by sharing valuable ideas, especially if we appropriate these ideas—i.e. present them as being our own, and not someone else's, whether that is the case or not (H1). However

In small scale societies, lethal attacks on another individual usually invite revenge by the victim's family. We might expect those who perpetrate such attacks to do so only when their own support network (mainly family) is larger than that of the potential victim so as to minimise the risk of retaliation. Using data from Icelandic family sagas, we show that this prediction holds whether we consider

Human child survival depends on adult investment, typically from parents. However, in spite of recent research advances on kin influence and birth order effects on human infant and child mortality, studies that directly examine the interaction of kin context and birth order on sibling differences in child mortality are still rare. Our study supplements this literature with new findings from large-scale

Moving in synchrony leads to cooperative behaviour and feelings of social closeness, and dance (involving synchronisation to others and music) may cause social bonding, possibly as a consequence of released endorphins. This study uses an experimental paradigm to determine which aspects of synchrony in dance are associated with changes in pain threshold (a proxy for endorphin release) and social bonding

Why should organisms incur a cost in order to inflict a (usually greater) cost on others? Such costly harming behavior may be favored when competition for resources occurs locally, because it increases individuals' fitness relative to close competitors. However, there is no explicit experimental evidence supporting the prediction that people are more willing to harm others under local versus global

Over our evolutionary history, humans have faced the problem of how to create and maintain social bonds in progressively larger groups compared to those of our primate ancestors. Evidence from historical and anthropological records suggests that group music-making might act as a mechanism by which this large-scale social bonding could occur. While previous research has shown effects of music making

A model proposed by Lukaszewski and Roney (2011) suggests that each individual's level of extraversion is calibrated to other traits that predict the success of an extraverted behavioural strategy. Under 'facultative calibration', extraversion is not directly heritable, but rather exhibits heritability through its calibration to directly heritable traits ("reactive heritability"). The current study

Popular theory suggests that facial averageness is preferred in a partner for genetic benefits to offspring. However, whether facial averageness is associated with genetic quality is yet to be established. Here, we computed an objective measure of facial averageness for a large sample (N = 1,823) of identical and nonidentical twins and their siblings to test two predictions from the theory that facial

For cooperation to evolve, some mechanism must limit the rate at which cooperators are exposed to defectors. Only then can the advantages of mutual cooperation outweigh the costs of being exploited. Although researchers widely agree on this, they disagree intensely about which evolutionary mechanisms can explain the extraordinary cooperation exhibited by humans. Much of the controversy follows from

Theories in both evolutionary and social psychology suggest that a positive correlation should exist between facial attractiveness and general intelligence, and several empirical observations appear to corroborate this expectation. Using highly reliable measures of facial attractiveness and IQ in a large sample of identical and fraternal twins and their siblings, we found no evidence for a phenotypic

Prior to, or concurrent with, the encoding of concepts into speech, the individual faces decisions about whether, what, when, how, and with whom to communicate. Compared to the existing wealth of linguistic knowledge however, we know little of the mechanisms that govern the delivery and accrual of information. Here we focus on a fundamental issue of communication: The decision whether to deliver information

Homophily, the tendency for people to cluster with similar others, has primarily been studied in terms of proximal, psychological causes, such as a tendency to have positive associations with people who share traits with us. Here we investigate whether homophily could be correlated with perceived group membership, given that sharing traits with other people might signify membership of a specific community

How to allocate resources between somatic maintenance and reproduction in a manner that maximizes inclusive fitness is a fundamental challenge for all organisms. Life history theory predicts that effort put into somatic maintenance (health) should vary with sex, mating and parenting status because men and women have different costs of reproduction, and because life transitions such as family formation

Evolutionary theory predicts that natural selection will fashion cognitive biases to guide when, and from whom, individuals acquire social information, but the precise nature of these biases, especially in ecologically valid group contexts, remains unknown. We exposed four captive groups of chimpanzees (Pan troglodytes) to a novel extractive foraging device and, by fitting statistical models, isolated

Humans find members of the opposite sex more attractive when their image is spatially associated with the color red. This effect even occurs when the red color is not on the skin or clothing (i.e. is extraneous). We hypothesize that this extraneous color effect could be at least partially explained by a low-level and biologically innate generalization process, and so similar extraneous color effects

In contemporary developed populations, stepfather presence has been associated with detrimental effects on child development. However, the proximate mechanisms behind such effects are yet to be fully explored. From a behavioural ecological perspective, the negative effects associated with stepfathers may be due to the reduced quantity and quality of investments children receive within stepfather households

Substantial theoretical and empirical evidence demonstrates that fertility entails economic, physiological, and demographic trade-offs. The existence of trade-offs suggests that fitness should be maximized by an intermediate level of fertility, but this hypothesis has not had much support in the human life-history literature. We suggest that the difficulty of finding intermediate optima may be a function

Could signallers use size contrast illusions to dishonestly exaggerate their attractiveness to potential mates? Using composite photographs of women from three body mass index (BMI) categories designed to simulate small groups, we show that target women of medium size are judged as thinner when surrounded by larger women than when surrounded by thinner women. However, attractiveness judgements of the

As biological and linguistic diversity, the world's cultural diversity is on decline. However, to date there are no estimates of the rate at which the specific cultural traits of a group disappear, mainly because we lack empirical data to assess how the cultural traits of a given population change over time. Here we estimate changes in cultural traits associated to the traditional knowledge of wild

Testosterone plays an important role in mediating male reproductive trade-offs in many vertebrate species, augmenting muscle and influencing behavior necessary for male-male competition and mating-effort. Among humans, testosterone may also play a key role in facilitating male provisioning of offspring as muscular and neuromuscular performance are deeply influenced by acute changes in testosterone

Ethnic categories uniquely structure human social worlds. People readily form stereotypes about these, and other social categories, but it is unclear whether certain dimensions are privileged for making predictions about strangers when information is limited. If humans have been living in culturally-structured groups for much of their evolutionary history, we might expect them to have adaptations for

We propose that intuitions about modern mass-level criminal justice emerge from evolved mechanisms designed to operate in ancestral small-scale societies. By hypothesis, individuals confronted with a crime compute two distinct psychological magnitudes: one that reflects the crime's seriousness and another that reflects the criminal's long-term value as an associate. These magnitudes are computed based