Whereas most people are biologically either male or female, their genetic interests are almost never aligned with just their own sex. Drawing on the evolutionary theory of inclusive fitness gained through relatives, we partition the effects of kin on fitness into those that derive from female versus male relatives. We argue that the balance of these female- and male-derived effects, which we call ‘Gendered

People vary widely in their attitudes towards how much their government should redistribute wealth. Evolutionary theory may shed light on why this variation occurs. Numerous studies have established an association between upper body strength and attitudes towards equality and wealth redistribution in males, showing that physically stronger men are more likely to hold self-serving beliefs on these issues

Humans are distinctive in their dependence upon products of culture for survival, products that have evolved cumulatively over generations such that many cannot now be created by a single individual. Why the cultural capacity of humans appears unrivalled in the animal kingdom is a topic of ongoing debate. Here we explore whether innovation and/or social learning propensities may constrain the ability

In many human societies, truth-making institutions are considered necessary to establish an officially valid or “received” description of some specific situation. These range from divination, oaths, and ordeals to judicial torture or trial by jury. In many cases, these institutions may seem odd or paradoxical, e.g., why would an ordeal reveal a defendant's guilt or innocence? Here we propose to address

Grandmothers play a crucial role in families enhancing grandchild wellbeing and survival but their effects can be context-dependent, and the children born in poor conditions are most likely to benefit from the investments made by helping grandmothers. In this study, we examined, for the first time, whether grandmothers' presence modified associations between adverse birth status and survival up to

Intergroup interaction can be hindered by legacies of conflict and group biases. Many studies have looked at intergroup attitudes and pro-sociality in the wake of intergroup conflict, but few have explicitly studied how the group affiliation of another person affects the willingness to interact economically, especially when the interactions concern contested issues. In this study, I investigate the

When humans engage in social interactions, they are often uncertain about what the possible outcomes are. Because of this, highly sophisticated cooperation strategies may not be very effective. Indeed, some models instead predict the emergence of ‘social heuristics’: simple cooperation strategies that perform well across a range of different situations. Here, we put these predictions to the test in

Humans usually favour members of their own group, ethnicity or culture (parochial cooperation), and punish out-group wrongdoers more harshly (parochial punishment). The evolution of parochial cooperation is mainly explained by intergroup conflict, as restricting cooperation to in-groups can provide a relative advantage during conflict. However, explanations for the evolution of parochial punishment

There is widespread concern in both the popular and academic literature that a surplus of men in a population intensifies mating competition between men, particularly unpartnered men, resulting in increased violence towards both men and women. Recent contributions challenge this perspective and argue that male mating competition and levels of violence will be higher when sex ratios are female-skewed

Interest in incorporating life history research from evolutionary biology into the human sciences has grown rapidly in recent years. Two core features of this research have the potential to prove valuable in strengthening theoretical frameworks in the health and social sciences: the idea that there is a fundamental trade-off between reproduction and health; and that environmental influences are important

Life history theory has become a prominent framework in the evolutionary social sciences, and the concept of trade-offs, the cornerstone of life history theory in studies on non-human taxa, has likewise been widely adopted. Yet, human life history research often assumes trade-offs without demonstrating them. This is not surprising given the practical difficulties in measuring trade-offs in long-lived

This meta-analytic review aims to address the mixed findings in previous research by quantifying the associations between early-life stress and risk, time, and prosocial preferences, and testing the boundary conditions of these associations. We meta-analyze 123 articles reporting 867 effect sizes among 199,019 adults to test different predictions from a life history perspective, a sensitization perspective

Research on social judgments of faces often investigates relationships between measures of face shape taken from images (facial metrics), and either perceptual ratings of the faces on various traits (e.g., attractiveness) or characteristics of the photographed individual (e.g., their health). A barrier to carrying out this research using large numbers of face images is the time it takes to manually

Human male height is one of the most conspicuous sexually dimorphic, phenotypic characteristics that affect how men are perceived both by men and women, impacting mate selection and intra-sexual competition. Testosterone is a key hormone linked to morphological masculinity and advantage in intra-sexual competition. To date, there have been limited studies linking height with testosterone levels. Here

Over the past decade, there is increasing interest in the ways in which environmental unpredictability shapes human life history development. However, progress is hindered by two theoretical ambiguities. The first is that conceptual definitions of environmental unpredictability are not precise enough to be able to express them in statistical terms. The second is that there are different implicit hypotheses

Parents with substance misuse provide their children with a potentially risky rearing environment. According to the evolutionary life history theory, such environments steer individuals towards faster reproductive strategy. However, parents providing their children with hazardous environments may also pass on genes associated with early parenthood. In register data on individuals born in Sweden 1973–1993

The marriage of older men to younger women is common across cultures. On one hand, husband-older marriage may serve the interests of both sexes, a conclusion broadly consistent with reported gender differences in mate preferences. On the other hand, men alone may benefit from such marriages at a cost to women if seniority enables men to exert dominance in conflicts of interest. Indeed, in public health

Debate over wealth redistribution plays a prominent role in society, but the causes of differences in support for redistribution remain contested. A recent three-person two-situation model suggests these differences are shaped by evolved motivational systems of self-interest, compassion, and dispositional envy. We conducted a close replication testing this prediction, all subjects were British, recruited

Acoustic signals function in intrasexual mating competition in a wide variety of species, including humans. The low voice pitch of human males has been proposed to represent an honest signal of formidability. Although voice pitch in men affects perceptions of size and dominance, it is relatively weakly associated with objective measures of formidability such as body size and strength. As a result,

For humans, voice pitch is highly flexible and, when lowered, makes male speakers sound more dominant, intimidating, threatening, and likely to aggress. Importantly, pitch lowering could not have evolved as a threat signal with these effects on signal receivers unless it were honest on average. Drawing on Enquist's retaliation-cost model, we tested the hypothesis that heterosexual men high in threat

Previous findings showing that people are reluctant to contact morally disgusting objects such as Nazi clothing have been interpreted as showing that immorality is perceived as physically contaminating. However, self-presentation concerns could underlie the apparent contagiousness of immorality: associating visibly with immoral stimuli risks reputation damage because observers infer immorality by association

Although humans' sense of smell is relatively diminished compared to other species, olfaction is still a central sensory modality through which people evaluate both potential threats and prospective romantic partners. Despite olfaction's role in interpersonal relationships and disease avoidant responses, however, it remains unknown whether variation in olfactory acuity is associated with disease- and

Need-based transfer systems pool risk among interdependent individuals. Such arrangements are bound by two simple rules: Ask for help only when in need and, if you are able, give help to others who ask. But there may be a temptation for individuals to break these rules for short-term personal profit. Here, we study one factor that may enforce honesty in need-based transfer relationships: the visibility

Men's voices may provide cues to overall condition; however, little research has assessed whether health status is reliably associated with perceivable voice parameters. In Study 1, we investigated whether listeners could classify voices belonging to men with either relatively lower or higher self-reported health. Participants rated voices for speaker health, disease likelihood, illness frequency,

Most moral psychology research has been conducted in Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies. As such, moral judgment, as a psychological phenomenon, might be known to researchers only by its WEIRD manifestations. Here, we start with evaluating Moral Foundations Theory (MFT) using the Moral Foundations Questionnaire, and follow up by building a bottom-up model of moral

Many researchers have turned to evolutionary theory to better understand diversity in leadership. Evolutionary theories of leadership, in turn, draw on ethnographic cases of societies thought to more closely resemble the smaller-scale, face-to-face communities in which humans evolved. Currently, though, there is limited systematic data on the nature of leadership in such societies. We coded 109 dimensions

Natural selection is a key mechanism of evolution, which results from the differential reproduction of individuals due to differences in phenotype. We describe fecundity selection on 13 anthropometric traits in a sample of 4000–10,000 of Estonian girls, who were born between 1937 and 1962 and measured at around 13 years of age. Direct selection favoured shorter, slimmer and lighter girls with smaller

The ability to choose the partners we interact with is thought to have been an important driver in the evolution of human social behavior, and in particular, our propensity to cooperate. Studies showing that humans prefer to interact with cooperative others is often cited as support for partner choice driving the evolution of cooperation. However, these studies are largely drawn from Western samples

There is considerable evidence that human male faces contain honest, detectable cues to their physical dominance, which are related to their objective facial masculinity. As such, some have argued that the extent to which observers' rate masculinised male faces as appearing more physically dominant is a useful measure of their ability to detect cues of dominance and threat in other men. We found across

Cognitive and evolutionary research has focused on the powerful deities of large-scale societies, yet little work has examined the smaller gods of animist traditions. In a study of the water spirit Sikameinan of the Mentawai people (Siberut Island, Indonesia), we address three questions: (1) Are smaller gods believed to enforce cooperation, especially compared to bigger gods in larger-scale societies

Voice pitch is the primary perceptual correlate of fundamental frequency (fo) and describes how low or high a voice is perceived by listeners. Prior research showed that men whose habitual voice pitch is lower are perceived to have stronger fighting ability. However, voice pitch is also flexible and can thus be used facultatively to signal states that change situationally, such as current aggressive

Clinicians in Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies are rethinking whether Post-traumatic Stress Disorder (PTSD) is caused solely by exposure to life-threatening experiences, or also by moral injury—witnessing or participating in acts that violate moral beliefs. However, while there are evolutionary hypotheses explaining PTSD as a response to physical danger, the

Moralizing religions encourage people to anticipate supernatural punishments for violating moral norms, even in anonymous interactions. This is thought to be one way large-scale societies have solved cooperative dilemmas. Previous research has overwhelmingly focused on the effects of moralizing gods, and has yet to thoroughly examine other religious moralizing systems, such as karma, to which more

Decades of research conducted in Western, Educated, Industrialized, Rich, & Democratic (WEIRD) societies have led many scholars to conclude that the use of mental states in moral judgment is a human cognitive universal, perhaps an adaptive strategy for selecting optimal social partners from a large pool of candidates. However, recent work from a more diverse array of societies suggests there may be

The evolutionary origin of Primates' exceptionally large brains is still highly debated. Two competing explanations have received much support: the ecological hypothesis and the social brain hypothesis (SBH). We tested the SBH in (n = 82) baboons (Papio anubis) belonging to the same research centre but housed in groups with size ranging from 2 to 63 individuals. We found that baboons living in larger

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