Human Nature-An Interdisciplinary Biosocial Perspective最新文献

Kin relations have a strong theoretical and empirical basis for explaining cooperative behavior. Nevertheless, there is growing recognition that context-the cooperative environment of an individual-also shapes the willingness of individuals to cooperate. For nomadic pastoralists in Norway, cooperation among both kin and non-kin is an essential predictor for success. The northern parts of the country are characterized by a history of herder-herder competition exacerbating between-herder conflict, lack of trust, and subsequent coordination problems. In contrast, because of a history of herder-farmer competition, southern Norway is characterized by high levels of between-herder coordination and trust. This comparative study investigates the relative importance of "cooperative context" and kinship in structuring cooperative behavior using an experimental gift game. The main findings from this study were that in the South, a high level of cooperation around an individual pushes gifts to be distributed evenly among other herders. Nevertheless, kinship matters, since close kin give and receive larger gifts. In contrast, kinship seems to be the main factor affecting gift distribution in the North. Herders in the North are also concerned with distributing gifts equally, albeit limiting them to close kin: the level of intragroup cooperation drives gifts to be distributed evenly among other closely related herders. The observed regional contrasts in cooperative decisions fit with the different historical levels of conflict and trust in the two regions: whereas herders in the South are affected by both cooperative context and kinship, kinship seems to be the main determinant of cooperation in the North.

Thermoregulation is often thought to be a key motivating factor behind the origins of clothing. Less attention has been given, however, to the production and use of clothing across traditional societies in contexts outside of thermoregulatory needs. Here I investigate the use of disguises, modesty coverings, and body armor among the 10 hunter-gatherer societies in the Probability Sample Files (PSF) within the Human Relations Area Files (HRAF) World Cultures database, with a particular focus on disguise cases and how they compare with strategies of deception across other taxa. The employment of disguises-defined as altering one's appearance for purposes of deceiving conspecifics or other animals-is noted for eight of the 10 societies, with their use occurring in contexts of hunting, religious or cult practices, and war or interpersonal violence. Most hunter-gatherer disguises demonstrated clear similarities to cases of visual deception found in other species, with the majority of examples fitting categories of animal mimicry, masquerading as plants, disruptive coloration (camouflage), or background matching (camouflage), while disguises unique to humans involved the impersonation of culture-specific "spirit-beings." Clothing for modesty purposes (nine societies) and body armor (six societies) are also noted. I propose that strategic initiatives by individuals or groups to disguise or conceal themselves represents one possible initial pathway to the cultural evolution of clothing. There are likely multiple potential (nonexclusive) social and functional pathways to the emergence of clothing outside of thermoregulatory needs.

Research has found that both cisgender and transgender androphilic males (i.e., males sexually attracted to and aroused by other adult males) have female-typical occupational preferences when compared with gynephilic males (i.e., males sexually attracted to and aroused by adult females). Moreover, whereas cisgender androphilic males' occupational preferences tend to be intermediate between those of gynephilic men and androphilic women, transgender androphilic males tend to have occupational preferences that are more similar to androphilic women. No study has directly compared both types of androphilic males within the same culture. The present study investigated occupational preference and its relation to childhood sex-atypical behavior (CSAB), among gynephilic men (n = 208), androphilic women (n = 138), and cisgender (n = 132) and transgender (n = 129) androphilic males from the Istmo region of Oaxaca, Mexico, where androphilic males are recognized as third gender, muxes. The study found large sex differences in occupational preferences (d = 2.80). Furthermore, both cisgender muxe nguiiu (d = 2.36) and transgender muxe gunaa (d = 3.44) reported having more sex-atypical occupational preferences compared with men. However, muxe gunaa reported higher female-typical occupational preferences than women (d = 0.59) and muxe nguiiu (d = 0.57), whereas muxe nguiiu and women did not differ (d = 0.08). These findings are consistent with the conclusion that sex-atypical occupational preferences are a cross-culturally universal aspect of male androphilia. Finally, CSAB was associated with sex-atypical occupational preferences among all participants. These findings suggest that a developmental continuity exists between childhood and adulthood sex-atypicality.

Tinbergen's classic "On Aims and Methods of Ethology" (Zeitschrift für Tierpsychologie, 20, 1963) proposed four levels of explanation of behavior, which he thought would soon apply to humans. This paper discusses the need for multilevel explanation; Huxley and Mayr's prior models, and others that followed; Tinbergen's differences with Lorenz on "the innate"; and Mayr's ultimate/proximate distinction. It synthesizes these approaches with nine levels of explanation in three categories: phylogeny, natural selection, and genomics (ultimate causes); maturation, sensitive period effects, and routine environmental effects (intermediate causes); and hormonal/metabolic processes, neural circuitry, and eliciting stimuli (proximate causes), as a respectful extension of Tinbergen's levels. The proposed classification supports and builds on Tinbergen's multilevel model and Mayr's ultimate/proximate continuum, adding intermediate causes in accord with Tinbergen's emphasis on ontogeny. It requires no modification of Standard Evolutionary Theory or The Modern Synthesis, but shows that much that critics claim was missing was in fact part of Neo-Darwinian theory (so named by J. Mark Baldwin in The American Naturalist in 1896) all along, notably reciprocal causation in ontogeny, niche construction, cultural evolution, and multilevel selection. Updates of classical examples in ethology are offered at each of the nine levels, including the neuroethological and genomic findings Tinbergen foresaw. Finally, human examples are supplied at each level, fulfilling his hope of human applications as part of the biology of behavior. This broad ethological framework empowers us to explain human behavior-eventually completely-and vindicates the idea of human nature, and of humans as a part of nature.

Religions "in the wild" are the varied set of religious activities that occurred before the emergence of organized religions with doctrines, or that persist at the margins of those organized traditions. These religious activities mostly focus on misfortune; on how to remedy specific cases of illness, accidents, failures; and on how to prevent them. I present a general model to account for the cross-cultural recurrence of these particular themes. The model is based on (independently established) features of human psychology-namely, (a) epistemic vigilance, the set of systems whereby we evaluate the quality of information and of sources of information, and (b) threat-detection psychology, the set of evolved systems geared at detecting potential danger in the environment. Given these two sets of systems, the dynamics of communication will favor particular types of messages about misfortune. This makes it possible to predict recurrent features of religious systems, such as the focus on nonphysical agents, the focus on particular cases rather than general aspects of misfortune, and the emergence of specialists. The model could illuminate not just why such representations are culturally successful, but also why people are motivated to formulate them in the first place.

Although a substantial literature in anthropology and comparative religion explores divination across diverse societies and back into history, little research has integrated the older ethnographic and historical work with recent insights on human learning, cultural transmission, and cognitive science. Here we present evidence showing that divination practices are often best viewed as an epistemic technology, and we formally model the scenarios under which individuals may overestimate the efficacy of divination that contribute to its cultural omnipresence and historical persistence. We found that strong prior belief, underreporting of negative evidence, and misinferring belief from behavior can all contribute to biased and inaccurate beliefs about the effectiveness of epistemic technologies. We finally suggest how scientific epistemology, as it emerged in Western societies over the past few centuries, has influenced the importance and cultural centrality of divination practices.

In some small-scale societies, a sexual division of labor is common. For subadult hunter-gatherers, the onset of this division dates to middle childhood and the start of puberty; however, there is apparently no physiological explanation for this timing. The present study uses an experimental approach to evaluate possible energetic differences by sex in gathering-related activities. The energetic cost of gathering-related activities was measured in a sample of 42 subjects of both sexes aged between 8 and 14 years. Body mass and other anthropometric variables were also recorded. Our results show that the energetic differences in the simulated gathering activities depend only on body mass. Both sexes expend a similar amount of energy during locomotion activities related to gathering. Discarding the energetic factor, the sexual division of tasks may be explained as an adaptation to acquire the skills needed to undertake the complex activities required during adulthood as early as possible. Carrying out gathering activities during childhood and adolescence could be favored by the growth and development cycles of Homo sapiens. Moreover, if most of the energetic costs of gathering activities depend on body mass, the delayed growth in humans relative to other primates allows subadults to practice these tasks for longer periods, and to become better at performing them. In fact, this strategy could enable them to acquire adults' complex skills at a low energetic cost that can be easily subsidized by other members of the group.

Gossip (evaluative talk about others) is ubiquitous. Gossip allows important rules to be clarified and reinforced, and it allows individuals to keep track of their social networks while strengthening their bonds to the group. The purpose of this study is to decipher the nature of gossip and how it relates to friendship connections. To measure how gossip relates to friendship, participants from men's and women's collegiate competitive rowing (crew) teams (N = 44) noted their friendship connections and their tendencies to gossip about each of their teammates. Using social network analysis, we found that the crew members' friend group connectedness significantly correlated with their positive and negative gossip network involvement. Higher connectedness among friends was associated with less involvement in spreading negative gossip and/or being a target of negative gossip. More central connectedness to the friend group was associated with more involvement in spreading positive gossip and/or being a target of positive gossip. These results suggest that the spread of both positive and negative gossip may influence and be influenced by friendship connections in a social network.

People often signal their membership in groups through their clothes, hairstyle, posture, and dialect. Most existing evolutionary models argue that markers label group members so individuals can preferentially interact with those in their group. Here we ask why people mark ethnic differences when interethnic interaction is routine, necessary, and peaceful. We asked research participants from three ethnic groups in southwestern Madagascar to sort photos of unfamiliar people by ethnicity, and by with whom they would prefer or not prefer to cooperate, in a wage labor vignette. Results indicate that southwestern Malagasy reliably send and detect ethnic signals; they signal less in the marketplace, a primary site of interethnic coordination and cooperation; and they do not prefer co-ethnics as cooperation partners in novel circumstances. Results from a cultural knowledge survey and calculations of cultural F_ST suggest that these ethnic groups have relatively little cultural differentiation. We concur with Moya and Boyd (Human Nature 26:1-27, 2015) that ethnicity is unlikely to be a singular social phenomenon. The current functions of ethnic divisions and marking may be different from those at the moment of ethnogenesis. Group identities may persist without group conflict or differentiation.