The Number of Cultural Traits Is Correlated with Female Group Size but Not with Male Group Size in Chimpanzee Communities

What determines the number of cultural traits present in chimpanzee (Pan troglodytes) communities is poorly understood. In humans, theoretical models suggest that the frequency of cultural traits can be predicted by population size. In chimpanzees, however, females seem to have a particularly important role as cultural carriers. Female chimpanzees use tools more frequently than males. They also spend more time with their young, skewing the infants' potential for social learning towards their mothers. In Gombe, termite fishing has been shown to be transmitted from mother to offspring. Lastly, it is female chimpanzees that transfer between communities and thus have the possibility of bringing in novel cultural traits from other communities. From these observations we predicted that females are more important cultural carriers than males. Here we show that the reported number of cultural traits in chimpanzee communities correlates with the number of females in chimpanzee communities, but not with the number of males. Hence, our results suggest that females are the carriers of chimpanzee culture

The Cultural Evolution of Democracy: Saltational Changes in A Political Regime Landscape

Transitions to democracy are most often considered the outcome of historical modernization processes. Socio-economic changes, such as increases in per capita GNP, education levels, urbanization and communication, have traditionally been found to be correlates or ‘requisites’ of democratic reform. However, transition times and the number of reform steps have not been studied comprehensively. Here we show that historically, transitions to democracy have mainly occurred through rapid leaps rather than slow and incremental transition steps, with a median time from autocracy to democracy of 2.4 years, and overnight in the reverse direction. Our results show that autocracy and democracy have acted as peaks in an evolutionary landscape of possible modes of institutional arrangements. Only scarcely have there been slow incremental transitions. We discuss our results in relation to the application of phylogenetic comparative methods in cultural evolution and point out that the evolving unit in this system is the institutional arrangement, not the individual country which is instead better regarded as the ‘host’ for the political system

Demographic histories and genetic diversity across pinnipeds are shaped by human exploitation, ecology and life-history

A central paradigm in conservation biology is that population bottlenecks reduce genetic diversity and population viability. In an era of biodiversity loss and climate change, understanding the determinants and consequences of bottlenecks is therefore an important challenge. However, as most studies focus on single species, the multitude of potential drivers and the consequences of bottlenecks remain elusive. Here, we combined genetic data from over 11,000 individuals of 30 pinniped species with demographic, ecological and life history data to evaluate the consequences of commercial exploitation by 18th and 19th century sealers. We show that around one third of these species exhibit strong signatures of recent population declines. Bottleneck strength is associated with breeding habitat and mating system variation, and together with global abundance explains much of the variation in genetic diversity across species. Overall, bottleneck intensity is unrelated to IUCN status, although the three most heavily bottlenecked species are endangered. Our study reveals an unforeseen interplay between human exploitation, animal biology, demographic declines and genetic diversity

An Open Resource for Non-human Primate Imaging.

Non-human primate neuroimaging is a rapidly growing area of research that promises to transform and scale translational and cross-species comparative neuroscience. Unfortunately, the technological and methodological advances of the past two decades have outpaced the accrual of data, which is particularly challenging given the relatively few centers that have the necessary facilities and capabilities. The PRIMatE Data Exchange (PRIME-DE) addresses this challenge by aggregating independently acquired non-human primate magnetic resonance imaging (MRI) datasets and openly sharing them via the International Neuroimaging Data-sharing Initiative (INDI). Here, we present the rationale, design, and procedures for the PRIME-DE consortium, as well as the initial release, consisting of 25 independent data collections aggregated across 22 sites (total = 217 non-human primates). We also outline the unique pitfalls and challenges that should be considered in the analysis of non-human primate MRI datasets, including providing automated quality assessment of the contributed datasets

Religion vs. Health

Religion may affect personal health in at least two ways. First, religious prescriptions concerning matters such as diet, waste, sexual relationships and social support networks may have actual health consequences. Second, religious healing practices may induce placebo and nocebo responses. Through such mechanisms, religion can result in both positive and negative health effects, depending on prescriptions and rituals involved. Contingent on magnitude, health effects may constitute an underestimated component in understanding the prevalence and persistence of religions in human societies. Health aspects of religion may have become important in human societies through natural selection of susceptibility to placebo responses from religious healing rituals, or through cultural selection of components of religions that involve functioning health advice or that have piggy-backed on practices invoking placebo responses. What exact significance health effects have for understanding the persistence and ubiquity of religions remains to be thoroughly investigated, however

Evolutionary explanations for religion: An interdisciplinary critical review

Some form of religion exists in every documented society on earth. However, ‘religion’ is a multifaceted phenomenon commonly including aspects, such as rituals, myths, rules and regulations concerning ethical behaviour, social practices and some form of belief in the supernatural (e.g. gods, spirits or souls). Due to its pervasiveness, many researchers of biological and cultural evolution have suggested that religion needs a universal evolutionary explanation. However, most proposed explanations have either treated religion as a single all-encompassing entity or only focused on a single or a few aspects of religion. We propose, instead, to carry out an extensive review of such suggested evolutionary explanations with the express aim of pairing up proposed explanations with religious components in order to form a more comprehensive depiction of causation and how religion and human cognition both have evolved, each influenced by the other. We also propose to summarise predictions and hypotheses that spring from each explanation, with the express aim of stating how each may be evaluated and tested. Crucially, different aspects of religion may have different explanations and different explanations may apply to several aspects of religion. Proposed explanations will be summarised in a series of thematically oriented scientific articles, as well as in a summary monograph. Our dual competencies, in evolutionary theory and religious studies, provide us with a unique opportunity to evaluate these issues from both a natural and a humanistic point of view