Religion & the Social Brain

(funded by the Templeton Religion Trust, grant 0153)

ISSR has recently completed a research project on Religion and the Social Brain, funded by the Templeton Religion Trust (TRT 0153), looking at the evolution of religion from the perspective of the ‘Social Brain’ theory of human evolution developed by Robin Dunbar. For Social Brain theory, religion is not an incidental feature of human evolution; it is crucial to the success of human evolution. The purpose of this blog is to summarise what we have found.


The theoretical background will be introduced in next month’s blog by Leon Turner on the Brain Opioid Theory of Social Attachment (BOTSA). However, in brief, it is assumed that religion evolved gradually and rather piecemeal; it is debatable when it should properly be called ‘religion’. However, it seems clear that it started with embodied practices rather than with cognition; cognition seems to be one of the later aspects of religion to develop, and the cognitive aspects of religion started with narrative before they became doctrinal. Trance dancing was the soil out of which religion emerged, as the endorphin release triggered by trance dancing also triggered various transcendent experiences. Reflection on those exceptional experiences led to a religious worldview.


The research project that ISSR has just completed has had multiple strands. One has involved phylogenetic analyses of ethnographic databases. Our newly-built Hunter-Gatherer Religion Database contains data on 85 historical societies from around the world. This database has allowed us to study the features of hunter-gatherer religious systems on an unprecedented scale. Existing theories about the evolution of religion often characterise hunter-gatherer religious systems as being largely unstructured. The findings from our database show that religious specialists were found in almost every society, and many of those specialists were paid professionals. We also find that structured, community-wide ritual events were widespread in hunter-gatherer societies, and often played an important role in the identities of societies. Evolutionary accounts of religion need to take better account of the complexity of beliefs and practices in hunter-gatherer societies.


We have also carried out research on contemporary religion. Some of this has been naturalistic, looking at markers of endorphin release such as pain tolerance, how that changes as a result of church services, and how it correlates with increases in feelings of group bonding. We have also undertaken lab studies in which we can investigate this in more tightly controlled conditions.


In a large field study, which included Christian and Afro-Brazilian churches, as well as a secular church (Sunday Assemblies), we found that social bonding and pain threshold increased from before the ritual service to after. The pain threshold effect (a proxy for endorphins release) was stronger in the Brazilian churches, than with the UK Christian churches. We found no change in the pain threshold for the secular services.


Across a five-week lab ritual intervention, comparing spiritual versus secular yoga training, we replicated the effects of the field study. We found that social bonding and pain tolerance increased from before the yoga sessions to after, and that the social bonding effect increased with time. We found no significant differences between the spiritual and the secular conditions, except that participants in the spiritual condition felt more connected to ‘something beyond’ than in the secular condition.


Finally, we conducted a double-blind lab/field study where we used an endorphin blocker (Naltrexone) to more directly test the effects of endorphins. We found that social bonding significantly decreased for participants taking the endorphin blocker compared to the placebo.


This is the first empirical test of the Social Brain Hypothesis applied to religion. The results suggest that rituals play an important role in social bonding and that endorphins are an important biological mechanism in fostering such feelings of social connectedness.


One of the best-known aspects of Social Brain theory is ‘Dunbar’s number’ (150), which seems to represent a limit on the size of a viable social network. We have investigated the significance of Dunbar’s number for contemporary religious life, and connected it with congregation size theory. We found that the Social Brain Hypothesis provides an accurate and useful account of the growth of church congregations, not only in the theoretical literature on the church growth, but also in interviews with clergy and large scale surveys of church members. The prediction from the Social Brain hypothesis of an optimal congregation size of 150, beyond which restructuring or replanting must occur to avoid a growth plateau, was broadly confirmed in empirical assessment.


Building on the Social Brain suggestion that a common worldview is an important component in religion we ran a series of online experiments using a cultural transmission paradigm to explore whether religious people think about the world, and give explanations for events in the world, differently to the way non-religious people do. We also used an online survey methodology to explore the relationship between active religious participation, size of friendship circles, degree of life satisfaction and the role of the religious community in providing active support networks and a sense of security.


New religious movements present a special opportunity to study processes linked to the emergence and formation of religion in recent history and the present day. We found that the Social Brain hypothesis provided a powerful lens through which to interpret the core social functions taking place within a  New religious Movement (NRM) such as the Panacea Society; it suggests that the emergence of NRMs may be a natural evolutionary process.


We have also explored the broader philosophical and theological implications of the Social Brain approach to religion. The most important implications of the project concern its potential to counter the individualism that pervades the current evolutionary cognitive science of religion (ECSR).  Although ECSR does not explicitly try to reduce human persons to machine-like entities, some of its most important claims fail to do justice to the idea of the individual person in the way that theologians and social scientists conceive it.  The social brain approach to religion and social bonding, by contrast, works with a much rounder idea of the individual human person.


This approach explores religion’s history primarily in terms of the evolution of particular ritualistic practices that bond people together by stimulating the endorphin system. By explaining the origins and development of religion through the gradual evolution of ritual practices rather than focusing primarily on natural cognitive capacities responsible for the origins and development of beliefs in gods, the Social Brain approach strongly emphasises the social context both of religion itself, and of religious believers. The incorporation of research into the endorphin stimulating capacities of religious rituals into the broader evolutionary study of religion deflects some of the criticism of the study of the evolution of religion has received for its individualistic bias.


Our other major write-up on this project by Leon Turner can be found by clicking here.


We have uploaded the keynote lectures from the Social Brain conference onto YouTube. They are posted here for your convience.

Lecture Video One: Prof. Robin Dunbar

Lecture Video Two: Prof. James W. Jones

Lecture Video Three: Prof. Celia Deane-Drummond

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