Pulotu: Database of Austronesian Supernatural Beliefs and Practices

Abstract

Scholars have debated naturalistic theories of religion for thousands of years, but only recently have scientists begun to test predictions empirically. Existing databases contain few variables on religion, and are subject to Galton’s Problem because they do not sufficiently account for the non-independence of cultures or systematically differentiate the traditional states of cultures from their contemporary states. Here we present Pulotu: the first quantitative cross-cultural database purpose-built to test evolutionary hypotheses of supernatural beliefs and practices. The Pulotu database documents the remarkable diversity of the Austronesian family of cultures, which originated in Taiwan, spread west to Madagascar and east to Easter Island–a region covering over half the world’s longitude. The focus of Austronesian beliefs range from localised ancestral spirits to powerful creator gods. A wide range of practices also exist, such as headhunting, elaborate tattooing, and the construction of impressive monuments. Pulotu is freely available, currently contains 116 cultures, and has 80 variables describing supernatural beliefs and practices, as well as social and physical environments. One major advantage of Pulotu is that it has separate sections on the traditional states of cultures, the post-contact history of cultures, and the contemporary states of cultures. A second major advantage is that cultures are linked to a language-based family tree, enabling the use phylogenetic methods, which can be used to address Galton’s Problem by accounting for common ancestry, to infer deep prehistory, and to model patterns of trait evolution over time. We illustrate the power of phylogenetic methods by performing an ancestral state reconstruction on the Pulotu variable “headhunting", finding evidence that headhunting was practiced in proto-Austronesian culture. Quantitative cross-cultural databases explicitly linking cultures to a phylogeny have the potential to revolutionise the field of comparative religious studies in the same way that genetic databases have revolutionised the field of evolutionary biology.

Cultural macroevolution matters

“…Previously published language-based phylogenies were used as a proxy for the population history of these cultures (52). These trees fit remarkably well with archaeological evidence that shows Austronesianspeaking cultures were some of the greatest ocean voyagers in human history, sailing from their homeland in Taiwan to settle on islands ranging in size from the 0.4-km 2 island of Anuta up to the 785,000-km 2 continental island of New Guinea (14,53,54). The archaeological, genetic, and linguistic evidence suggests that this expansion started ∼5,000 y ago and spread in a series of expansion pulses and pauses through Island South East Asia and the Pacific (52)(53)(54)(55).…”

“…However, clichés can be true. Certainly, there are a growing number of global comparative cultural and linguistic databases, such as D-PLACE (2), DRH (7), WALS (8), ASJP (9), and Phoible (10), as well as relatively large regional databases, such as the Austronesian Basic Vocabulary Database (11), SAILS (12), Chirilla (13), and Pulotu (14). Although these databases might not technically qualify as "big data," they are large enough to afford the application of the type of sophisticated computational methods that are often used in the biological sciences such as network analysis of reticulate evolution, epidemiological models, and phylogenetic comparative methods.…”

“…Using this approach and data from the Pulotu database (14, 49), we recently tested a series of hypotheses about the role of religion in the emergence of social complexity (14,50,51). The Pulotu database contains quantitative variables documenting the traditional religious beliefs and practices as well as the social organization of 106 Austronesian cultures.…”

“…The Pulotu database contains quantitative variables documenting the traditional religious beliefs and practices as well as the social organization of 106 Austronesian cultures. Special care was taken in the coding of these data to ensure that, as far as possible, the coding reflected the state of the culture before conversion to major world religions and colonization (14). Previously published language-based phylogenies were used as a proxy for the population history of these cultures (52).…”

“…Population sizes ranged from ∼200 people on Anuta (58) to approximately half a million people in the case of the Merina of Madagascar (59). No less diverse were their religious systems, with supernatural beliefs including anthropomorphic, animistic, and nature deities, and religious rituals ranging in scale from humble personal offerings to multiday community-wide festivals (14). Because Austronesian cultures were some of the last cultures in the world to have contact with major world religions, and their traditional beliefs were well documented, they provide an ideal sample for testing theories about the role of religion in the emergence of social complexity.…”