تکامل نمایشگرهای پر هزینه، همکاری و مذهب: اعتبار افزایش نمایش و پیامدهای آن برای تکامل فرهنگی

This paper lays out an evolutionary theory for the cognitive foundations and cultural emergence of the extravagant displays (e.g., ritual mutilation, animal sacrifice and martyrdom) that have so tantalized social scientists, as well as more mundane actions that influence cultural learning and historical processes. In Part I, I use the logic of natural selection to build a theory for how and why seemingly costly displays influence the cognitive processes associated with cultural learning — why do “actions speak louder than words?” The core idea is that cultural learners can both avoid being manipulated by their models (those they are inclined to learn from) and more accurately assess their belief commitment by attending to displays or actions by the model that would seem costly to the model if he held beliefs different from those he expresses verbally. Part II examines the implications for cultural evolution of this learning bias in a simple evolutionary model. The model reveals the conditions under which this evolved bias can create stable sets of interlocking beliefs and practices, including quite costly practices. Part III explores how cultural evolution, driven by competition among groups or institutions stabilized at alternative sets of these interlocking belief-practice combinations, has led to the association of costly acts, often in the form of rituals, with deeper commitments to group beneficial ideologies, higher levels of cooperation within groups, and greater success in competition with other groups or institutions. I close by discussing the broader implications of these ideas for understanding various aspects of religious phenomena.

Researchers from across the behavioral sciences have long proposed a connection between apparently costly displays — often in various ritualized forms such as firewalking, ritual scarification, animal sacrifice and subincision — and deep levels of commitment to group ideologies, religious beliefs and shared values that promote solidarity and in-group cooperation (Atran and Norenzayan, 2004, Cronk, 1994, Durkheim, 1995, Irons, 1996, Rappaport, 1999 and Sosis and Alcorta, 2003). This paper provides a novel approach to understanding these observations by considering how natural selection might have shaped our cognitive processes for cultural learning so as to give salience to certain kinds of displays or actions, and what the implications of such cognitive processes are for cultural evolution. Since my goal is merely to get this approach on the table, where it can compete with alternatives, I aim to provide a prima facie case for considering these ideas, and not a set of conclusive tests.

I began by hypothesizing that, over the course of human evolution, cultural learners faced an adaptive challenge created by our increasing capacities for symbolic (cheap) cultural transmission. To meet this challenge natural selection favored a reliance on CREDs in determining how much to commit to, or believe in, a particular representation. Learners evolved to look for displays (often actions) that indicate a model's degree of commitment to, or belief in, verbally expressed representations. These CREDs are actions that (a) are consistent with a model's professed beliefs, and (b) a model would be unlikely to perform if he believed something different from what he expressed symbolically. Building on this, I examined the implications of this evolved bias for cultural evolution by constructing a simple formal model. The model reveals a wide range of conditions under which this reliance on CREDs can create multiple stable states, with one of these involving an interlocking combination of a costly practice and a belief. Such situations can arise when (1) particular practices influence the transmissibility of certain belief adoptions (CREDs), (2) committing to a belief favors some practices over others (compatibility content bias) and (3) learners tend to copy more successful people (prestige-bias cultural learning).