Evolution and Human Behavior最新文献

Occupation of the foraging niche requires an extensive body of ecological knowledge, and humans rely heavily on social learning to master this curriculum in a safe, efficient, timely manner. This presents a formidable information management problem: In the absence of writing, how did ancestral hunter-gatherer societies accurately store and transmit their accumulated knowledge from generation to generation? Pronounced patterns in forager oral story corpora suggest a partial answer. Cross-culturally, these stories exhibit similar themes, genres, and characters, which in turn map onto critical domains of ecological knowledge. These stories also exhibit pronounced consistencies in their formal properties, predictably utilizing strategies that engage attention (e.g., ostensive communication) and facilitate memorization (e.g., repetition, rhythm, imagery). These patterns suggest that storytelling is an information technology that addresses key problems posed by our entry into the information niche: in conjunction with other forms of symbolic behavior (e.g., ritual, visual art, song, dance, games) storytelling provides a mnemonic framework for encoding accumulated knowledge, rules for faithfully copying it, and regular occasions for refreshing and transmitting it. Collectively, these behaviors may have been instrumental in the emergence of cumulative culture.

The tendency for women, relative to men, to more strongly prefer mates with good financial prospects has been reliably documented across a variety of cultures. Malovicki-Yaffe et al. (2018) provided data to the contrary, demonstrating that Haredi women of the ultra-Orthodox community in Israel care little for a wealthy partner. They reported no significant sex difference in ratings of a partner's economic prospects, and a reversal for trait rankings, such that men rated a woman's earning capacity as more important than women did. These findings illustrate that status is culturally determined. The most conservative members of the ultra-Orthodox community in Israel endorse a sociocultural agreement in which women enter the workforce as the breadwinner to enable men to devote their time to religious pursuits. As a consequence, little power can be earned by men for their wealth, but is instead presumed to be conferred by their status as a religious scholar. Women's preferences follow suit, with a strong desire to acquire a highly intelligent and educated religious scholar as a mate. This sociocultural arrangement is still practiced within the ultra-Orthodox community, but recent shifts toward modernization in religious beliefs among some sects provide an opportunity to build on past research in three ways (1) replicate the reversed sex difference in mate preferences for economic prospects with a larger and more religiously varied sample (N = 1414 via an online Haredi Panel, Study 1), (2) examine whether the sex-reversed effect is weaker among those who have shifted to more modern religious beliefs (Study 1), and (3) validate the underlying assumptions made by past work with respect to how Haredi men and women earn power (N = 949 via online convenience sampling, Study 2). The results document a sex reversal in mate rankings and ratings for economic prospects, demonstrate that this effect is strongest among the most religiously conservative Haredi people, and confirm that men's strongest source of power in the ultra-Orthodox community is their role as a Torah scholar—eclipsing the impact of wealth. Additionally, we demonstrate the stability of men's preferences for a young and attractive partner, and explore whether women's role as an economic breadwinner translates into power in the home or community.

Human society rests on communicated information, much of which is shared without an expectation of reward. We suggest that, like other forms of prosociality, this type of information provision is fueled by gratitude. To reflect the fact that information differs in some ways from other goods, we call this form of gratitude epistemic gratitude. In a first experiment (all preregisterered, with US participants), we show that participants are more grateful for information that provides more benefits, at a greater cost to the sender, that was sent intentionally, and gratuitously. Experiment 2 shows that information shared with a large audience generates less gratitude in individual audience members. Experiment 3 shows that information that can be further passed on to others elicits more gratitude. In the supplementary materials, we also report a series of inconclusive experiments testing whether gratitude increases when an initially doubted piece of information is confirmed, and whether participants think others communicate in a way that maximizes gratitude in the audience. In conclusion, we speculate on the consequences of epistemic gratitude—in particular, which type of information is more likely to elicit epistemic gratitude—for diverse cultural phenomena, from personalization in marketing to rumor diffusion.

In low fertility settings, religious people tend to have larger families than non-religious people. One way religious individuals may achieve larger relative family sizes is through support from their families. In this paper, we investigate the relationships between religiosity, kin contact, allomaternal investment from relatives, and fertility in two high income low fertility settings: the United Kingdom and the United States. Data for this pre-registered research come from an online survey of 609 women living in the US and 919 women living in the UK, recruited through Prolific, who answered questions about their religious practices, childbirth histories, social networks, and allomaternal networks. We find that, compared with less religious peers, more religious women: 1) have more geographically diffuse kin networks (particularly in the UK) but have social networks that are equally kin-dense; 2) receive more allomaternal support from kin beyond their partner, particularly help with household tasks, though the countries differ in the exhibited relationship between religiosity and partner support; and 3) have higher fertility in both countries. We do not find strong evidence for a mediating role of allomaternal support on the relationship between religiosity and fertility. Our study highlights important variation in the relationship between religion and fertility across two high income low fertility countries and raises new questions about the role that religion plays in allomaternal support networks in these settings.

Costly ritual behaviours have frequently been of interest to evolutionary researchers seeking to understand whether they have an adaptive benefit. Here we examine the costliness of initiation rituals across a large group of hunter-gather societies in Pama-Nyungan Australia and compare these with a range of possible adaptive benefits, including warfare, food sharing, demography, and mate competition. We find that in Australia, desert habitat was mostly strongly associated with these rites. Such rites may support the collective action, such as food sharing, necessary for survival in such a precarious environment.

Religious practices vary greatly worldwide. Lifelong celibacy is present in many world religions, but it remains unclear why the frequency of monks and nuns (male and female celibates) varies at different times and places. Here, we develop a two-sex inclusive fitness model of lifelong celibacy. We find that the sex that competes more over parental resources is favoured to have more celibates, that is more monks than nuns are expected when brother-brother competition is higher than sister-sister competition. Moreover, the extent to which brothers and sisters compete over the same parental resources influences these patterns: intermediate sibling competition leads to more extreme differences in the proportion of monks and nuns. The sex that disperses less is also favoured to have more celibates. We show how our model can explain variation in the frequency of monks and nuns in three populations that differ in post-marital residence, marriage systems and inheritance rules.