Evolution and Human Behavior最新文献

Mate choice is a fitness-relevant decision, that can be informed by the mate choices of others. Such mate-choice copying has been documented across multiple species, including humans. However, so has copying in many other contexts. As such, the exent to which mate-choice copying is underpinned by the same psychological mechanisms as copying in other contexts remains unclear. To test these hypotheses, we conducted an online experiment (recruiting from M-Turk, n = 165) to examine whether human mate choice copying is prestige and/or conformist biased (both of which are documented in other domains), and whether it differs between men and women. If mate choice copying is underpinned by broad-context mechanisms, we predict it will be similar in men and women, with both groups also exhibiting prestige-biased and conformist transmission. Our results match these predictions, exhibiting no evidence of a difference in mate-choice copying between men and women, and evidence of prestige-biased and conformist transmission. These results suggest that mate choice copying is the product of adaptive, broad-context copying mechanisms.

Life history theory applied to human development stipulates that humans have evolved to detect and encode information from the early developmental environment that entrain coordinated development pathways. One possible mechanism is epigenetic age acceleration but few studies have prospectively examined associations between epigenetic aging and life-history related phenotypes. The purpose of this study was to examine the relations between epigenetic age acceleration when children were age 7 years and indices of reproductive development during adolescence using a sample of N = 512 youth from the Avon Longitudinal Study of Parents and Children (ALSPAC). A path model was used to test direct and indirect associations between epigenetic age acceleration and age at menarche (AAM), age at first sex, and lifetime and past year sexual partner number. Results showed epigenetic age acceleration was directly associated with earlier age at first sex and increased sexual partner number. There were further indirect associations with sexual partner number via age at first sex. Epigenetic age acceleration was not associated with AAM. Follow-up analyses to determine if aspects of the early developmental environment were associated with age acceleration were null. Implications for life history theory and the need for additional research are discussed.

Gender inequalities in status and prestige are common across many populations, but while considerable attention has been paid to understanding the drivers of men's status, the causes and consequences of women's status have received scant attention, particularly outside industrialized contexts. We combine demographic, health and dyadic rating data from an endogamous community to show that women of higher status have improved outcomes for themselves and their children. We find perceptions of generosity, intelligence, and respectfulness best predict women's status. Women of greater status marry higher quality partners and have children with better growth outcomes, results similar to those found for men across cultures, but rarely demonstrated in women. The results suggest women's status can be an important driver of fitness-related outcomes, and should be considered alongside men's status in evolutionary studies.

Within evolutionary psychology, a dominant assumption is that adaptive variation in fast versus slow life history strategies centrally includes variation in sociosexual orientations. Fast reproductive strategies—prioritizing current reproduction and high number of low-quality offspring—are purportedly facilitated by short-term, uncommitted sexual relationships with multiple partners and investing little in resulting offspring (a high mating effort, low parental effort strategy). Slow strategies—of producing few, high-quality offspring—purportedly entails having few lifetime sexual partners and forming long-term, committed pair-bonds in which both parents invest heavily in offspring (a high parental effort, low mating effort strategy). Notably, proposals for individual variation in human life history strategies are inspired by cross-species evidence on covariation of traits related to reproduction and longevity. However, examination of evidence across mammals, birds, and primates reveals that variations in mating versus parental effort are not central to the interspecies dimensions of fast-slow strategies. Variations in pair-bonding and biparental care likewise do not map onto the fast-slow continuum or offspring quantity versus quality dimension. Indeed, in human foraging groups, male provisioning appears to increase offspring quantity. For several reasons, sex with multiple partners does not promote women's fertility rate. Alternative selection pressures are more likely to have led to adaptive variation in human mating strategies.

We present a study testing the existence and correlates of personality concepts in the village of Conambo, Ecuador, which is home to horticultural-foragers located in the Sápara Territory of the Ecuadorian Amazon. Lexical terms to describe the three focal personality concepts from the HEXACO taxonomy—Sociability, Immodesty, and Un-emotionality—were interpreted from Spanish into the Indigenous languages of Achuar and Quichua. These terms were employed in a photo ranking task wherein 76 adult community members ranked the relative standing of same-sex others on each personality concept. Inter-ranker agreement was high for Sociability and Immodesty, but low for Un-emotionality. We tested the associations among individual differences in (i) Sociability and Immodesty, (ii) hierarchical status and fertility, which are hypothesized fitness-linked benefits of high Sociability and Immodesty, and (iii) physical strength, which is a hypothesized calibrator of status-oriented personality strategies. Using Bayesian models and psychological networks including age controls, we found good evidence that men's physical strength associated positively with Sociability, Immodesty, and status. Among both sexes, Sociability and Immodesty exhibited strong positive correlations with status, but evidence was weaker that the personality traits associated with fertility. Status associated positively with fertility among both sexes. We conclude that two personality concepts imported from the HEXACO and Big Five taxonomies, Sociability and Immodesty, exist with common meaning in the minds of Conambo villagers and appear adaptively patterned in relation to physical strength and fitness-linked outcomes. We argue that the photo ranking task employed in this research produces personality assessments with high validity and should therefore be adopted in future studies of individual differences in face-to-face groups.

Humans transmit cultural information to others in a variety of ways that can affect productivity, cultural success, and ultimately fitness. Not all potential transmitters are expected to be equally preferred by learners or equally willing to influence their culture acquisition. Across socioeconomic opportunities and ages in the human life course, costs and benefits to both learners and potential transmitters are expected to vary, affecting rates of culture transmission from different vectors. Here we examine reported patterns of culture transmission contributing to 92 essential skills among a sample of 421 Tsimane forager-farmers native to Bolivia. Consistent with the expectation that the costly provision of support and cultural information typically flows from older to younger generations in a subsistence society, we find that the development of essential knowledge and skills is primarily influenced by older same-sex relatives, especially parents. Grandparents are more often reported as transmitters for low-strength/high-difficulty skills that they have comparative advantage in, such as storytelling and musical performance. Though less frequent, same generation peers are more likely to provide discouragement in the learning process and to transmit modern, market-oriented skills. Our findings suggest that kinship, gender, generational seniority, and skill type together explain the vectors and styles of influence responsible for essential culture transmission. The multigenerational pedagogy documented here helps facilitate successful economic and social production in a complex skills niche dependent on multigenerational cooperation, such as observed in human hunter-gatherers and other subsistence populations.

Previous research argues that female choice may not be as powerful an influence on the evolution of human mating preferences as once expected given the importance of parental choice in marital practices across cultures. Furthermore, much of the literature supporting this argument assumes that endorsed cultural norms reported in the ethnographic record accurately represent individuals' behaviors. Here, we argue that the roles of parent-offspring conflict and parental choice are more nuanced. We test predictions from parent-offspring conflict theory and illuminate three loci of conflict between parents and daughters over partner choice. Using data from over 10 years of fieldwork in Shuar communities, we demonstrate that endorsed norms do not reflect complete behavioral repertoires at the individual level. We conclude that analyzing individual behavior provides insight into (1) areas of parental-offspring conflict and (2) complementary aspects of female choice and parental choice.

For most of human evolution, accumulated cultural knowledge has been stored in memory and transmitted orally. This presents a daunting information management problem: how to store and transmit this knowledge in a portable format that resists corruption. One solution–widespread among foragers–is to encode knowledge in narrative. However, this strategy depends on accurate performance of the story. Significantly, some forager cultures have rules regulating myth performance, although the extent of this phenomenon is unknown. We hypothesize that these rules subserve high-fidelity transmission across generations. Accordingly, we predicted that, across forager cultures, myth-telling rules will mandate: (P1) transmission by the most proficient storytellers (P2) under low-distraction conditions with (P3) multiple individuals and (P4) multiple generations present, and the application of measures that (P5) prevent, identify, and/or correct errors, (P6) maintain audience attention, (P7) discourage rule violations and/or (P8) incentivize rule compliance. To test these predictions, we searched the forager ethnographic record for descriptions of myth performance, and coded them for prescriptions/proscriptions regarding narrator age, performance context, audience composition, narrative delivery, and audience comportment, as well as sanctions associated with rule transgression or compliance. Results indicate that rules regulating myth performance are widespread across forager cultures, and are characterized by features that reduce the likelihood of copy errors. These findings help elucidate the role that anthropogenic ratchets played in the emergence of cumulative culture.

The near totality of human mate choice research occurs in large-scale, urban, industrial populations. It is unclear to what extent lessons learned from such populations reflect generalizable features of human mating psychology as opposed to localized responses to the demands of these historically unusual environments. Here, we use couple simulation, an agent-based modeling technique, to compare models of mate choice across both a U.S. sample (n = 1678) and a sample of k = 15 couples from Conambo, Ecuador—a relatively remote community of horticultural-foragers in the Ecuadorian Amazon. The Conambo sample provides a unique opportunity to evaluate models of mate choice in that (1) this sample represents approximately 50% of the households within this community and (2) all of the participants in this sample are acquainted with one another. Participants in Conambo completed a ranking task in which each participant ranked each opposite-sex adult in the community in terms of their quality as a spouse. We used these rankings to simulate the mating market in Conambo under alternative models of mate choice. We find that these models are able to reproduce Conambo marriages at a high degree of accuracy and perform comparably across both the Conambo sample and U.S. samples. Specifically, the resource allocation model performs best in reproducing mate choices in both the U.S. and Conambo samples. These results suggest that at least some aspects of human mating psychology generalize across both large-scale industrialized and small-scale populations.