Large-scale societies in which strangers regularly engage in mutually beneficial transactions are puzzling. The evolutionary mechanisms associated with kinship and reciprocity, which underpin much of ...primate sociality, do not readily extend to large unrelated groups. Theory suggests that the evolution of such societies may have required norms and institutions that sustain fairness in ephemeral exchanges. If that is true, then engagement in larger-scale institutions, such as markets and world religions, should be associated with greater fairness, and larger communities should punish unfairness more. Using three behavioral experiments administered across 15 diverse populations, we show that market integration (measured as the percentage of purchased calories) positively covaries with fairness while community size positively covaries with punishment. Participation in a world religion is associated with fairness, although not across all measures. These results suggest that modern prosociality is not solely the product of an innate psychology, but also reflects norms and institutions that have emerged over the course of human history.
Suicidality is an important contributor to disease burden worldwide. We examine the developmental and environmental correlates of reported suicidal ideation at age 15 and develop a new evolutionary ...model of suicidality based on life history trade-offs and hypothesized accompanying modulations of cognition. Data were derived from the National Longitudinal Survey of Children and Youth (Statistics Canada) which collected information on children’s social, emotional, and behavioral development in eight cycles between 1994 and 2009. We take a model selection approach to understand thoughts of suicide at age 15 (N ≈ 1,700). The most highly ranked models include social support, early life psychosocial stressors, prenatal stress, and mortality cues. Those reporting consistent early life stress had 2.66 greater odds of reporting thoughts of suicide at age 15 than those who reported no childhood stress. Social support of the primary caregiver, neighborhood cohesion, nonkin social support of the adolescent, and the number of social support sources are all associated with suicidal thoughts, where greater neighborhood cohesion and social support sources are associated with a reduction in experiencing suicidal thoughts. Mother’s prenatal smoking throughout pregnancy is associated with a 1.5 greater odds of suicidal thoughts for adolescents compared to children whose mother’s reported not smoking during pregnancy. We discuss these findings in light of evolutionary models of suicidality. This study identifies both positive and negative associations on suicidal thoughts at age 15 and considers these in light of adaptive response models of human development. Findings are relevant for mental health policy.
Inheritance and inequality among nomads of South Siberia Hooper, Paul L; Reynolds, Adam Z; Jamsranjav, Bayarsaikhan ...
Philosophical transactions of the Royal Society of London. Series B. Biological sciences,
08/2023, Letnik:
378, Številka:
1883
Journal Article
Recenzirano
Odprti dostop
At the headwaters of the Yenisei River in Tuva and northern Mongolia, nomadic pastoralists move between camps in a seasonal rotation that facilitates their animals' access to high-quality grasses and ...shelter. The use and informal ownership of these camps depending on season helps illustrate evolutionary and ecological principles underlying variation in property relations. Given relatively stable patterns of precipitation and returns to capital improvement, families generally benefit from reusing the same camps year after year. We show that locations with higher economic defensibility and capital investment-winter camps and camps located in mountain/river valleys-are claimed and inherited more frequently than summer camps and camps located in open steppe. Camps are inherited patrilineally and matrilineally at a ratio of 2 : 1. Despite its practical importance, camp inheritance is not associated with livestock wealth today, which is better predicted by education and wealth outside the pastoral economy. The relationship between the livestock wealth of parents and their adult children is significantly positive, but relatively low compared to other pastoralists. The degree of inequality in livestock wealth, however, is very close to that of other pastoralists. This is understandable considering the durability and defensibility of animal wealth and economies of scale common across pastoralists. This article is part of the theme issue 'Evolutionary ecology of inequality'.
Costly Punishment Across Human Societies Henrich, Joseph; McElreath, Richard; Barr, Abigail ...
Science (American Association for the Advancement of Science),
06/2006, Letnik:
312, Številka:
5781
Journal Article
Recenzirano
Recent behavioral experiments aimed at understanding the evolutionary foundations of human cooperation have suggested that a willingness to engage in costly punishment, even in one-shot situations, ...may be part of human psychology and a key element in understanding our sociality. However, because most experiments have been confined to students in industrialized societies, generalizations of these insights to the species have necessarily been tentative. Here, experimental results from 15 diverse populations show that (i) all populations demonstrate some willingness to administer costly punishment as unequal behavior increases, (ii) the magnitude of this punishment varies substantially across populations, and (iii) costly punishment positively covaries with altruistic behavior across populations. These findings are consistent with models of the gene-culture coevolution of human altruism and further sharpen what any theory of human cooperation needs to explain.
Innovative teaching knowledge stays with users Lane, A. Kelly; McAlpin, Jacob D.; Earl, Brittnee ...
Proceedings of the National Academy of Sciences - PNAS,
09/2020, Letnik:
117, Številka:
37
Journal Article
Recenzirano
Odprti dostop
Programs seeking to transform undergraduate science, technology, engineering, and mathematics courses often strive for participating faculty to share their knowledge of innovative teaching practices ...with other faculty in their home departments. Here, we provide interview, survey, and social network analyses revealing that faculty who use innovative teaching practices preferentially talk to each other, suggesting that greater steps are needed for information about innovative practices to reach faculty more broadly.
Instructional reform in STEM aims for the widespread adoption of evidence based instructional practices (EBIPS), practices that implement active learning. Research recognizes that faculty social ...networks regarding discussion or advice about teaching may matter to such efforts. But teaching is not the only priority for university faculty – meeting research expectations is at least as important and, often, more consequential for tenure and promotion decisions. We see value in understanding how research networks, based on discussion and advice about research matters, relate to teaching networks to see if and how such networks could advance instructional reform efforts. Our research examines data from three departments (biology, chemistry, and geosciences) at three universities that had recently received funding to enhance adoption of EBIPs in STEM fields. We evaluate exponential random graph models of the teaching network and find that (a) the existence of a research tie from one faculty member
i
to another
j
enhances the prospects of a teaching tie from
i
to
j
, but (b) even though faculty highly placed in the teaching network are more likely to be extensive EBIP users, faculty highly placed in the research network are not, dimming prospects for leveraging research networks to advance STEM instructional reforms.
Variability in men’s reproductive success (RS) is partly attributable to the ability of successful men to influence resource flows relevant to the mate choice and reproduction of women. This study ...explores the effects of variability in resource flows on men’s RS in an indigenous foraging/mixed-economy community in northern Siberia where monogamous marriage norms predominate. A series of material, embodied, and relational wealth indicators are tested as predictors of men’s age-adjusted RS and age at first birth. Material wealth related to hunting, embodied wealth as represented by hunting skill, and relational wealth as represented by numbers of kin are the most consistent predictors of men’s RS. In this monogamous population, the wives of men with more hunting capital and of men rated as better hunters have shorter interbirth intervals, and hunters show strong producer priority. These findings and ethnographic observations appear more consistent with a provisioning model than with a signaling-for-mates model.
While it is commonly assumed that farmers have higher, and foragers lower, fertility compared to populations practicing other forms of subsistence, robust supportive evidence is lacking. We tested ...whether subsistence activities-incorporating market integration-are associated with fertility in 10,250 women from 27 small-scale societies and found considerable variation in fertility. This variation did not align with group-level subsistence typologies. Societies labeled as "farmers" did not have higher fertility than others, while "foragers" did not have lower fertility. However, at the individual level, we found strong evidence that fertility was positively associated with farming and moderate evidence of a negative relationship between foraging and fertility. Markers of market integration were strongly negatively correlated with fertility. Despite strong cross-cultural evidence, these relationships were not consistent in all populations, highlighting the importance of the socioecological context, which likely influences the diverse mechanisms driving the relationship between fertility and subsistence.
Subsistence food sharing in Ust’-Avam (Taimyr Region, Russian Federation) is analyzed in light of Arctic research on sharing and current debate. Cultural traditions such as food sharing practices are ...widespread across indigenous communities in the Arctic and are arguably fundamental to the sustainability of indigenous Arctic cultures and their ability to buffer against environmental disequilibrium. Sharing diaries from 10 respondents over 12 weeks in August and October 2001, describe 162 distributions among 69 household dyads. Independent variables, including household relatedness, reciprocal sharing, and interaction effects, influence the documented food sharing pattern. Economic need and social association also influence sharing. Indicators of risk buffering are weaker than in two previous analyses of food sharing in Ust’-Avam that focus on primary distributions after the hunt and interhousehold meal sharing. Consideration of sharing by nonhunters provides an opportunity to examine explanatory hypotheses of food sharing, illustrating the nuances and robusticity of social ecology in indigenous subsistence economies.
In the face of economic and political changes following the end of the Soviet Union, total fertility rates fell significantly across the post-Soviet world. In this study we examine the dramatic ...fertility transition in one community in which the total fertility rate fell from approximately five children per woman before 1993 to just over one child per woman a decade later. We apply hypotheses derived from evolutionary ecology and demography to the question of fertility transition in the post-Soviet period, focusing on an indigenous community (Ust’-Avam) in the Taimyr Region, northern Russia. We employ a mixed parametric accelerated failure-time model that allows comparison of age at first birth, interbirth interval, and reproductive postponement or cessation prior to and following 1993. We find that short-term reproductive delay alone does not explain the dramatic drop in fertility in Ust’-Avam. Age at first birth remains constant. Interbirth intervals increase moderately. The estimated fraction of women who have ceased or indefinitely postponed reproducing doubles (for parities 2 through 4) or triples (for nulliparous women). We caution against assuming that environmental harshness necessarily leads to earlier and more rapid reproduction. An evolutionary theory of fertility responses to acute environmental shocks remains relatively undeveloped. In such contexts it is possible that selection favors a conservative reproductive strategy while more information is learned about the new environment. When investigating fertility responses to environmental stressors we suggest researchers examine postponement and stopping behavior in addition to changes in age at first birth and interbirth interval.
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