Historical and ethnographic evidence suggests that people around the world use supernatural beliefs to explain misfortune. The cross-cultural prevalence of this pattern may arise from our expectations that norm violations lead to sanctioning. In cases where an outcome seems punitive yet lacks an identifiable cause, individuals, motivated to fill this explanatory gap, may rely on beliefs in supernatural punishment to make sense of what has happened. If true, supernatural explanations for misfortunes should be more common when a victim is believed to have not cooperated in the past (i.e., in cases where misfortunes might be unexplained but otherwise appear deserved). Using a vignette experiment across nine diverse populations (N = 714), including African hunter-gatherers and Melanesian horticulturalists, we tested if knowledge of past bad actions increased participants' endorsements of supernatural causes for misfortune. Across all populations, participants rated a misfortune as more likely to be supernaturally caused when the victim was known to have failed to reciprocate a favour or engage in generous actions towards others in the past. This was slightly increased when the behaviour was additionally labelled normative. Responses to open-ended free-listing questions provide additional evidence that when the victim was known to be uncooperative, participants were more likely to propose supernatural causes for misfortune as well as supernatural solutions. Additional normative labelling had only a small effect. Together, these findings suggest that when misfortunes lack clear causes, people's motivation to explain interacts with moral evaluations, leading them to invoke supernatural beliefs most commonly when misfortune appears deserved.
Witchcraft beliefs, or the idea that certain individuals can use magic to harm others, have been widespread historically and remain prevalent in many regions, but their socioecological correlates and potential functions remain unclear. Accusations of harmful magic commonly occur where witchcraft beliefs are socially salient and may provide a means of imposing costs on competitors in contexts of resource competition. We created a global dataset on the presence or absence of witchcraft beliefs in small-scale societies (n = 242) and combined this with socioecological variables from Murdock's Ethnographic Atlas (EA). Using phylogenetic comparative methods, we tested whether witchcraft beliefs are associated with socioecological conditions, particularly those relating to resource competition and conflict. Witchcraft beliefs were less common in mobile hunter-gatherer societies than in sedentary agricultural societies, consistent with the possibility that mobility provides opportunities to mitigate conflict through physical separation. Beliefs were also more common in societies with class divisions than in relatively egalitarian societies, but declined in societies characterised by complex stratification, suggesting a nonlinear relationship between social inequality and witchcraft beliefs. We found no association between witchcraft beliefs and environmental uncertainty, while phylogenetic covariation suggests that cultural history also contributes to their distribution. However, variation remained among relatively egalitarian societies. These findings suggest that both socioecological pressures and cultural history contribute to the distribution of witchcraft beliefs.
Cultural evolutionary theory has long modeled offspring trait variance as constant across generations, an assumption borrowed from quantitative genetics that has remained largely untested. We examine this by comparing a Parental Variability-Dependent Inheritance (PVDI) model, in which offspring variance scales with parental variance, against the classic Galton-Pearson model, using physical artifacts transmitted across three generations in a cross-cultural experiment spanning Prague and two communities in Cameroon. The PVDI model outperformed alternatives in all tasks, though its expression was modulated by learner background rather than task domain. Cumulative improvement emerged in the engineering but not the aesthetic task, driven by individual-level innovation rather than performance-biased selection. These findings challenge a foundational assumption of the field, make a strong case for cross-cultural designs in cultural evolution research, and introduce a novel framework for the parametrization of the cultural transmission process.
Testosterone has been hypothesized to help explain sex differences in pathogen disgust sensitivity (PDS), which is a measure of how intensely one experiences disgust toward pathogen threats. Guided by the sexual selection framework, researchers have theorized testosterone may downregulate PDS to facilitate mating effort. Yet, this relationship remains largely untested outside women samples. The present study (total N = 355) assessed salivary testosterone and PDS in three distinct populations: A sample of adults from Boston including 1) cisgender men (N = 116), 2) transmasculine adults on hormone therapy (N = 30), and 3) a longitudinal sample of juveniles and adolescents from Utila, Honduras (N = 209; 119 girls). Across all cohorts, testosterone showed no significant associations with PDS. Collectively, we found no evidence that testosterone levels meaningfully shape PDS, regardless of developmental stage, route, or level of hormone exposure.
