David Sloan Wilson’s essay provides ample fodder for provocative discussion on cultural evolution. Are cultural traits adaptations, and if so, at what level(s) of selection? These questions can only be resolved on a case-by-case basis but that will mean we also need to know much more about how cultural traits and groups change over time. It can be misleading to offer hypotheses to explain present day group behaviors without considering forces molding the past. We cannot assume that the same underlying processes affecting emerging groups in the distant past are still at work in those groups today. Below we use religious traditions as examples of cultural groups more generally but our arguments would be equally applicable to secular polities or financial corporations.
It is possible that religions emerge and flourish because they are adaptive for their members or for religious groups or both. Those that persist as a consequence may undergo further growth and perhaps indefinite evolution, but the cultural transformations that have resulted in the major religions we see today may not have been selected in a Darwinian sense. Even if they are, then present day selection might not operate at the same level as in the past. Once a religious tradition is established, individual decisions and behaviors continue to influence group dynamics as a (metaphorical) “tug-of-war”: group governance seeks to maintain (or perhaps increase) numbers of adherents, whereas individuals seek fulfillment as members, perhaps leaving the group if the perceived benefits of defection outweigh the costs. If a religious tradition were to go extinct as a consequence this is not necessarily because of competition between religious groups. A group could simply lose members without any distinctive outside influence. Successful groups that continue to grow and (perhaps slowly) evolve will express emerging behaviors that do not stem from selection in the distant past. Rather, they are evolving “survival machines”, much like invasive species or (and no deeper parallels intended) cancer.
It is possible that the rate at which religious groups expand or contract can be predicted largely by internal factors. For example, a simple rule of thumb may be that the longer a tradition has been established the harder it becomes to eradicate due to the ‘weight of tradition’ (and all that implies psychologically). On this view, established religions with deep histories do continue to evolve, but the institutions change their functions over time not as a consequence of between-group competition, but only because the needs of the tradition change as the system matures. In this scenario, we are left with a time course in the life-cycle of a human group: initially requiring Darwinian selection on culture towards increased expectations of individual survival and/or productivity (which may be tied to group performance and competitive ability), but through time, involving more diffuse forces that continually shape the group, and depend less and less on survival of the fittest and more on group maintenance through internal adaptation to more complex environments (internal and external).
Cultural group selection may be a more prominent feature of warring groups. When tribes or states go to war the fates of individuals may become closely entwined with those of the group. Sedentarism and territoriality may contribute to these processes. But even in these circumstances, processes of cultural group selection are likely to be complex, since the characteristics of prevailing polities will depend on among other things, history, bordering states, local environments, cultural composition, etc.
We can actually test these hypotheses empirically. In much of the debate responding to David Sloan Wilson’s essay the question of evidential support is somewhat neglected.
Historians, anthropologists and evolutionary biologists can combine forces to study recent and present day religious cults, or hunter-gatherers that either make or don’t make the transition to sedentarism. They can study insurgencies and nation states. They can investigate .com startups and established firms and industries. There is a trove of simple questions waiting to be answered. What are the characteristics of groups that survive and those that do not? What are the individual and group level traits associated with different demographic trajectories, such as membership or employment? Is there good evidence for competition being reduced and/or cooperation being fostered within groups? What are the associated traits (individual, group)? Do these nascent groups, once gaining a foothold “reproduce”, spawning spatially distinct daughter groups? Are traits transferred to new groups with high fidelity (otherwise said, what is trait heritability)? For the oldest of these groups where histories are sufficiently detailed, did they experience a “transition” in their past that permitted them to go from a cult or emerging status to one that is more established, and in so doing, grow in membership number? Finally, and critically, does this transition process occur via measurable Darwinian processes, and if so, at what level(s) does it occur?
Michael E. Hochberg (University of Montpellier II, France; Santa Fe Institute, USA)
Harvey Whitehouse (University of Oxford, UK)