Evolution and Human Behavior最新文献

Children have evolved “psychological weapons” to endear them to adults, enhancing their chances of surviving. Earlier research has shown that, during early childhood, caregivers feel positively attracted by children's vocal and cognitive cues of immaturity, which in turn provide adults with information about children's attributes and needs. The purpose of this study was to disentangle which of these two cues (vocal or cognitive), if either, might be more relevant for adults in assessing children's attributes and needs. College students (n = 273) listened to four pairs of children reasoning either in a mature or an immature manner about two types of thinking, one we labeled supernatural that reflects “magical thinking” (e.g., “The sun's not out because it's mad”) and the other we labeled natural that reflects abilities such as estimating one's cognition abilities or inhibition (e.g., “I can remember all the words you showed me”). In one condition (Consistent), the immaturity/maturity of children's reasoning matched the immaturity/maturity of their voices, whereas in the other condition (Inconsistent) they did not. Results revealed that, regardless of the type of reasoning, children's vocal cues prevailed over cognitive cues for assessing attributes of positive affect and helplessness. Conversely, children's cognitive cues prevailed over vocal cues for assessing intelligence (but only for supernatural thinking), and negative affect (but only for natural thinking). The results reveal natural selection's use of different cues of immaturity to promote caregiving during early childhood and reflect the complexity of multimodal features when adults evaluate young children.

The costly signaling theory of religion states that costly religious behaviors, badges, and bans (“religious practice” for short) are signals of commitment to the ingroup and its moral code. Such signals are proposed to increase cooperation. Here we review the empirical literature, which suggests that religious actors are often perceived as especially trustworthy and may be more likely recipients of help and cooperation. The evidence does not present a clear picture regarding the actual trustworthiness nor prosocial tendencies of religious actors. Limited available evidence suggests that routine forms of religious behavior are associated with ingroup favoritism. High-cost, infrequent, highly social forms of religious practice are associated with an increase in religious identity, but also an expanded social identity and greater tolerance for outgroup members. Following the literature review, we provide a discussion of proposed future research directions pertaining to the costs and benefits of religious practice, moderators, secular versus religious practice, and mediation of the relationship between observed religious practice and perceptions of religious actors' trustworthiness.

While scholars largely agree men's infidelity evolved by increasing offspring quantity, the evolutionary drivers of women's infidelity remain debated. The “good genes” (dual mating strategy) hypothesis posits infidelity allows women to pair the preferred genes of an affair partner with the preferred investment of their primary partner (Gangstad & Thornhill, 1998). The mate-switching hypothesis instead argues infidelity helps women obtain a new mate without a period of deprivation (Buss et al., 2017). To test these hypotheses, we conducted a pre-registered survey of 254 individuals from 19 countries and 6 continents who were previously or currently engaged in infidelity. We measured individuals' perception of their primary partner and their affair partner across four domains: physical attractiveness, personal attractiveness, attractiveness as a co-parent, and overall desirability (mate value). We also asked participants to report their motivations for the affair. Consistent with a dual mating strategy, women experienced stronger physical attraction to their affair partners and stronger parental attraction to their primary partners. Contrary to the mate-switching hypothesis, women did not prefer their affair partners overall, parentally, or personally. There were no significant gender differences in these findings, suggesting strategic dualism in men as well. Our qualitative data revealed a more nuanced story at the individual level, with participants reporting motives consistent with a variety of evolutionarily coherent strategies. While our quantitative results speak to the relevance of the dual-mating hypothesis to understanding infidelity, our findings also suggest that seeking infidelity's primary explanation in either gender is, perhaps, too simple an approach to the issue.

What past selection pressures have shaped human traits and their variation and covariation across individuals? These are key questions in the evolutionary social sciences. Recent advances in the field of human genomics have yielded a wealth of evidence that sheds light on these questions, yet the findings and their implications seem to be little known in the evolutionary social sciences. In this paper I aim to bring together these findings while explaining the conceptual and technical background that is often assumed knowledge for reading the primary reports. First, I outline the genomics methodologies that have enabled the relevant findings, such as genomewide association studies and DNA-based heritability estimation. I describe how these methodologies reveal the genetic architecture of traits, and then how this information in turn enables inferences about past selection. The findings show pervasive evidence that the genetic architecture of complex traits has been shaped by negative (purifying) selection, implying that the extant genetic variation in the traits has been maintained by mutation-selection-drift balance. On the other hand, there is no evidence that balancing selection has substantively shaped complex traits, and strong evidence that it has not. Finally, I discuss the implications of these findings for issues such as the dimensional structure of personality variation and the plausibility of psychological life history theory.

This study responds to Martin Daly's critique of our 2022 study on the correlation between income inequality and homicide rates in Mexican municipalities. Our updated analysis incorporates both immediate and lagged effects of income inequality, revealing significant non-linear relationships between past inequality and current homicide rates. We find that higher levels of past inequality interact with present inequality to increase homicide rates, particularly among currently average and highly unequal municipalities –not so much in less unequal municipalities. These findings support Daly's argument that economic inequality's influence on violent behavior accumulates over time, highlighting the need for a time dimension in homicide rate models. Our study emphasizes the importance of considering historical economic conditions when addressing socio-economic determinants of homicide, aiming to contribute constructively to ongoing attempts to effectively reduce homicidal violence.

We examined how children reason about dominance and prestige in Colombia, Finland, and the USA, contexts that vary in terms of societal inequality and hierarchical organization. We tested 496 children aged 4–11 years old to determine whether they: i) recognized and discriminated between dominance and prestige, ii) preferred to learn from a dominant or prestigious character, iii) assigned leadership to a dominant or prestigious character, and iv) self-identified more with a dominant or subordinate character. Older children were more likely to recognize, prefer, learn from, and assign leadership to the prestigious character, and to identify with the subordinate. There were no cross-cultural differences in learning preferences, supporting evolutionary theories that posit a universal bias towards social learning from prestigious individuals. There was variation in leadership preferences; children were the most likely to assign leadership to a prestigious character in more egalitarian Finland, and least likely in more unequal Colombia. We argue that societal factors including levels of inequality and hierarchical social organization shape an underlying propensity for children to learn to reason about rank and to broadly favor prestige in leaders and models for learning from.

The adaptive benefits of cooperation among humans have been widely studied. However, is being cooperative always adaptive across various combinations of ecological conditions? Existing work has focused on cultural, inter-, and intra-individual predictors of cooperation yet there is a lack of research on how an individual's ecology may come into play. In this work, we focus on the interaction of two ecological factors—population density and resource scarcity—on cooperation. Population density is often accompanied by social competition for limited resources. We hypothesise that in response to cues of high (versus low) population density, people facing resource-scarcity would adaptively lower their cooperativeness, more so than those with resource abundance. Results from two studies support our hypothesis—population density lowers cooperation, but only for people who perceive lower resources or social status. Our findings provide insights that cooperation varies adaptively as a function of interacting ecological factors.

Gendered divisions of labor are a feature of every known contemporary hunter-gatherer (forager) society. While gender roles are certainly flexible, and prominent and well-studied cases of female hunting do exist, it is more often men who hunt. A new study (Anderson et al., 2023) surveyed ethnographically known foragers and found that women hunt in 79% of foraging societies, with big-game hunting occurring in 33%. Based on this single type of labor, which is one among dozens performed in foraging societies, the authors question the existence of gendered division of labor altogether. As a diverse group of hunter-gatherer experts, we find that claims that foraging societies lack or have weak gendered divisions of labor are contradicted by empirical evidence. We conducted an in-depth examination of the data and methods of Anderson et al. (2023), finding evidence of sample selection bias and numerous coding errors undermining the paper's conclusions. Anderson et al. (2023) have started a useful dialogue to ameliorate the potential misconception that women never hunt. However, their analysis does not contradict the wide body of empirical evidence for gendered divisions of labor in foraging societies. Furthermore, a myopic focus on hunting diminishes the value of contributions that take different forms and downplays the trade-offs foragers of both sexes routinely face. We caution against ethnographic revisionism that projects Westernized conceptions of labor and its value onto foraging societies.

Trait inferences from faces are pervasive, but sometimes misleading. Past research indicates Americans infer hunting and gathering ability from others' faces, but the accuracy of these perceptions remains unknown. In three studies, we test whether Americans can accurately perceive foraging ability from faces. We used three datasets from two traditional subsistence societies (the Hadza and the Tsimane) in which individuals were photographed and evaluated by their peers on their ability to hunt or gather effectively (N = 175). US MTurkers (N = 579) then evaluated the photos for foraging ability. We found that MTurkers' perceptions of men consistently tracked peer-evaluated hunting ability (overall r = 0.25), suggesting that naïve perceptions of men's productivity from a face photo alone reflect actual hunting ability. MTurkers' perceptions of women's productivity inversely correlated with their peer-evaluated gathering ability, however. We discuss potential mechanisms and implications for research on social perception.

Cross-sectional studies suggest that local ecological knowledge (LEK) helps humans cope with their environment. Among the forms of LEK, adult knowledge of wild plants has been associated with better child and adult health. We assess if the concurrent links between i) LEK and ii) health and nutritional status last and examine if LEK yields delayed benefits when societies face large socioeconomic and environmental changes. We use a yearly panel (2002−2010) from Tsimane’, an Indigenous Amazonian society (Bolivia). All adults (∼440) and children (∼300) measured at baseline (2003) in 13 villages were followed yearly during 2004–2010 to estimate associations between a) baseline adult knowledge and skill about uses of wild plants and b) subsequent (2004–2010) anthropometric markers of nutritional status of themselves and the children (2y ≤ age ≤ 10y) living in the household at baseline. Among children, HAZ, BMI, and sum of four skinfolds were measured; among adults, BMI, sum of four skinfolds, and percent body fat with bioelectrical impedance were measured. Some skill losses increased by a large amount the likelihood of severe childhood stunting (HAZ < -3) for girls; the complete loss of these skills increased the share of severely stunted girls from 5% to 13%–20%. These are big numbers. The effects of LEK on other anthropometric indicators of children or adults were small. For example, if all adults in a household lost all their ethnobotanical knowledge, children's and women's BMI would decrease by only 3% and 11%, respectively.