Human Nature-An Interdisciplinary Biosocial Perspective最新文献

Humans often display extensive forms of prosocial behavior, frequently beyond what is predicted by inclusive fitness. This observation has led to various models attempting to explain the unique extent of human altruism. While many of these models have been empirically tested, one model, the ancestor-descendant conflict model, which is based on a maximum descendant-leaving strategy, has yet to be explicitly examined with observational human data. The ancestor-descendant conflict model posits that ancestors influence the behavior of their descendants, through traditions passed down from generation to generation, and predicts that humans in traditional societies will favor, both altruistically and cooperatively, their closer kin even at greater genealogical distances than predicted by inclusive fitness. In this paper, we specifically examine the strength of ancestor influence on prosociality using observational (n = 863) and interview (n = 28) data collected with the Iban of West Kalimantan, Indonesia (Borneo). We evaluate kinship cooperation norms, kinship's role in cooperative interactions, and the strength of ancestor influence on those interactions with dyadic data (unique dyads = 668). We find strong norms and behaviors for individuals cooperating more often with closer kin, while also finding limited support for the influence of ancestors on actual cooperative behavior.

Recent research has shown that an array of religious beliefs can be used to enforce socially normative behaviour, but the application of these theories to other supernatural beliefs, including witchcraft, is still nascent. Across two pre-registered studies in Mauritius, we examine how witchcraft is believed to be caused by envy and how this belief can create and enforce social norms around not causing envy. Data was collected in-person in Mauritius. In study 1 (N = 445), we found that both practicing witchcraft and being motivated by envy or self-interest increase perceptions of harm. These motivations also increase the rate with which people suggest a person was doing witchcraft, with envy having the stronger effect. Belief that someone was doing witchcraft increases the negativity with which one views that person and damages their reputation. In study 2 (N = 292), we found that when a person breaks a norm around causing envy, participants believe that a subsequent misfortune is cause by witchcraft, but not by God. When someone acts selfishly towards others a subsequent misfortune is believed to be caused by God but not witchcraft. This suggests that witchcraft beliefs, but not religious ones, are enforcing norms around preventing envy. Together, these studies suggest that witchcraft beliefs can support locally specific social norms, and that these norms might be different than those supported by religion.

Human fascination with art has deep evolutionary roots, yet its role remains a puzzle for evolutionary theory. Although its widespread presence across cultures suggests a potential adaptive function, determining its evolutionary origins requires more comprehensive evidence beyond mere universality or assumed survival benefits. This paper introduces and tests the Collector Hypothesis, which suggests that artworks serve as indicators of collectors' surplus wealth and social status, offering greater benefits to collectors than to artists in mating and reproductive contexts. Our study among Indigenous Papuan communities provides preliminary support for the Collector Hypothesis, indicating that, compared to artists, collectors are perceived as having higher social status and greater attractiveness to women. These findings provide unique insights into Papuan communities and contribute to the ongoing discussion about art's adaptive significance of art by suggesting that artistic capacities may benefit not only creators but also those who accumulate and display art. Further research in diverse cultural contexts is needed for a comprehensive understanding of this interplay.

This study aims to reveal the nature and motivation of human cooperation. By adopting the public goods game paradigm of competition and repetition, and introducing factors such as punishment and heterogeneous contributions, an experiment was conducted at Nanjing University in China, where 224 undergraduate students participated in seven games, including intragroup and intergroup competition. Meanwhile, participants' social value orientation (SVO) was measured. The results indicated that cooperation (non-zero contribution) was the common choice for participants, but their contributions varied across rounds and games. Individuals generally act as conditional free-riders in intragroup competition games, i.e., they use the "small for big" strategy. In contrast, individuals generally act as conditional cooperators in intergroup competitive games, i.e., they use the "tit for tat" strategy. Although SVO should theoretically be related to contribution, analysis revealed that participants' contributions were not significantly dominated by SVO, but were primarily driven by self-interest. Specifically, individuals switch back and forth between conditional cooperators and conditional free-riders to seek maximum self-interest. Our results not only reveal the complexity and strategic nature of human behavior in competitive contexts but also highlight the central role of self-interest in driving individual decision-making, reflecting the balance between individuals' pursuit of self-interest and adaptation to the environment in social interactions.

Given the ubiquitous nature of love, numerous theories have been proposed to explain its existence. One such theory refers to love as a commitment device, suggesting that romantic love evolved to foster commitment between partners and enhance their reproductive success. In the present study, we investigated this hypothesis using a large-scale sample of 86,310 individual responses collected across 90 countries. If romantic love is universally perceived as a force that fosters commitment between long-term partners, we expected that individuals likely to suffer greater losses from the termination of their relationships-including people of lower socioeconomic status, those with many children, and women-would place a higher value on romantic love compared to people with higher status, those with fewer children, and men. These predictions were supported. Additionally, we observed that individuals from countries with a higher (vs. lower) Human Development Index placed a greater level of importance on romantic love, suggesting that modernization might influence how romantic love is evaluated. On average, participants worldwide were unwilling to commit to a long-term romantic relationship without love, highlighting romantic love's universal importance.

Considering the role of human interactions in infectious disease outbreaks and cooperation in mitigating natural disasters consequences, ecological threats to human survival have been among proposed drivers of collectivism. Utilizing established and novel measures of parasite stress and natural disasters, we investigated their association with collectivism in a large sample of countries (N = 188). Linear mixed-effect models indicated that after controlling for national wealth, neither natural disasters nor infectious disease can predict collectivism scores. Null results were consistent across different measures of threats, suggesting that previous findings can be attributed to small, non-representative samples of cultures. When universal patterns are a major concern, drawing conclusions based on small, nonrepresentative subsets of cultures risks promoting unreliable findings. Future cross-cultural research will benefit from data-driven exploratory methods to uncover factors previously unexamined in the theory-driven studies of collectivism.

This study examined whether supermarkets can be considered patches in the marginal value theorem (MVT) sense despite their particular features and whether they are models of human food foraging in resource-dense conditions. On the basis of the MVT, the quantitative relationship between gains in the Euro and patch residence time was modeled as an exponential growth function toward an upper asymptote, allowing the choice of an optimal strategy under diminishing returns. N = 61 participants were interviewed about their current shopping trip and contextual variables at a German supermarket and provided data to estimate relevant model parameters. A nonlinear model of the patch residence time and resulting gain based on an exponential function was fitted via nonlinear orthogonal distance regression. The results generally revealed the relationships predicted by the model, with some uncertainty regarding the estimation of the upper asymptote due to a lack of data from participants with long residence times. Despite this limitation, the data support the applicability of the MVT-based model. The results show that approaches from optimal foraging theory, such as the MVT, can be used successfully to model human shopping behavior even when participants' verbal reports are used.

The coordination of beliefs, norms, and behaviors is foundational to theories of group formation. However, because beliefs and norms are not directly observable, signaling mechanisms are required to build reliable signals of latent traits. Although the mathematical theory behind these signals is robust, there is very little testing of ethnic marker theory or of its key propositions that markers become more prevalent along ethnic boundaries and where more than two cultural groups are in contact. We present an ethnographic test of this theory with phonetic differences serving as potential group signals. The data derive from an ethnographic and linguistic investigation in two contrasting secondary school settings in Utah, one that is majority European American and one that is ethnically more diverse. Word list recordings were collected as part of interviews with teens from different backgrounds. We extracted acoustic data from the speech of European Americans (EAs) and Pacific Islanders (PIs), then analyzed differences in the pronunciation of the vowel in words such as "bit." We found evidence of greater phonetic marking at the more diverse school, along more prominent boundaries of ethnic interaction. These results align with predictions made by the theoretical models. This initial empirical test of model predictions provides justification for the development of more complex models that could account for more variables within the environment.

We study game-theoretic models of human evolution to analyze fundamentals of human nature. Rival-claimants games represent common situations in which animals can avoid conflict over valuable resources by mutually recognizing asymmetric claiming rights. Unlike social-dilemma games, rival-claimants games have multiple equilibria which create a rational role for communication, and so they may be good models for the role of language in human evolution. Many social animals avoid conflict by dominance rankings, but intelligence and language allow mutual recognition of more complex norms for determining political rank or economic ownership. Sophisticated forms of economic ownership could become more advantageous when bipedalism allowed adaptation of hands for manufacturing useful objects. Cultural norms for claiming rights could develop and persist across generations in communities where the young have an innate interest in learning from their elders about when one can appropriately claim desirable objects. Then competition across communities would favor cultures where claiming rights are earned by prosocial behavior, such as contributions to public goods. With the development of larger societies in which many local communities share a common culture, individuals would prefer to interact with strangers who identifiably share this culture, because shared cultural principles reduce risks of conflict in rival-claimants games.

How old is war? Is it a deep-seated propensity in the human species or is it a recent cultural invention? This article investigates the archaeological evidence for prehistoric war across world regions by probing two competing hypotheses. The "deep roots" thesis asserts that war is an evolved adaptation that humans inherited from their common ancestor with chimpanzees, from which they split around seven million years ago, and that persisted throughout prehistory, encompassing both nomadic and sedentary hunter-gatherer societies. In contrast, the "shallow roots" viewpoint posits that peaceful intergroup relations are ancestral in humans, suggesting that war emerged only recently with the development of sedentary, hierarchical, and densely populated societies, prompted by the agricultural revolution ~ 12,000-10,000 years ago. To ascertain which position is best supported by the available empirical evidence, this article reviews the prehistoric archaeological record for both interpersonal and intergroup conflict across world regions, following an approximate chronological sequence from the emergence of humans in Africa to their dispersal out of Africa in the Near East, Europe, Australia, Northeast Asia, and the Americas. This worldwide analysis of the archaeological record lends partial support to both positions, but neither the "deep roots" nor the "shallow roots" argument is fully vindicated. Intergroup relations among prehistoric hunter-gatherers were marked neither by relentless war nor by unceasingly peaceful interactions. What emerges from the archaeological record is that, while lethal violence has deep roots in the Homo lineage, prehistoric group interactions-ranging from peaceful cooperation to conflict-exhibited considerable plasticity and variability, both over time and across world regions, which constitutes the true evolutionary puzzle.