The target article is an important contribution to the study of cultural evolution and an impressive account of the emergence of group-level traits. In Smaldino's view, norm-enforcing institutions and cultural narratives are necessary for maintaining suites of cultural traits, such as organizational patterns, behavioral norms, and cooperative decision-making heuristics. If these traits are maintained over time, they will potentially contribute to the emergence of group-level traits. These are the phenotypic effects of social organization and interdependent collaborations that are made possible only when individuals with differentiated roles are structurally cooperative and socially coordinated. Furthermore, because religion is one of the most effective mechanisms for transmitting whole suites of cultural traits, such as hierarchies that reinforce the group's social organization, it is one of the most important constituents of traits at the group level.
We are in general agreement with Smaldino's account, but we think he has overlooked two crucial points about religion: its unique role in stabilizing prosocial norms and its distinct effectiveness at transmitting suites of cultural traits. Approaching religion as an institution, as Smaldino does, can lead to worthwhile insights about the social structures that support religion and the function of religion as a cultural organization. However, analyzing religions as complex systems more accurately reveals the structures that maintain religions, as well as the traits that emerge from them. Religious systems consist of core interdependent features, such as rituals, supernatural agent beliefs, and myths, which evolved independently but at some point in human history began to co-occur and coevolve regularly and cross-culturally (Alcorta & Sosis Reference Alcorta and Sosis2005; Purzycki & Sosis Reference Purzycki, Sosis, Voland and Schiefenhovel2009; Sosis Reference Sosis2009). As anthropologists observe, elements of religious systems interact in complex ways, resulting in emergent properties (e.g., Geertz Reference Geertz1973) and creating communities with shared customs, cognitive schemas, historical memories, and identities.
Although we are critical of Smaldino's characterization of religion as a norm-enforcing institution, we believe that an adaptive systems approach is consistent with his argument for the emergence of group-level traits and provides various explanatory advances to his conception of religion. We address each of these advantages in what follows. In doing so, we hope to show that, from a cultural evolutionary perspective, religion is better conceived as a complex adaptive system rather than a norm-enforcing institution.
First, understanding religion as a complex adaptive system clarifies how religions succeed at transmitting suites of cultural behaviors while concurrently adapting to varying socioenvironmental conditions. Religious systems achieve this apparent opposition by maintaining hierarchies of religious discourse, in which adherents focus on core statements of belief that remain unchanged, even as interpretations of those statements change over time. Accordingly, adherents typically accept novel interpretations of fundamental postulates as being reifications of eternal or personally relevant truths, while taking little notice of the modifications to religious rules and social norms with each generation (Rappaport Reference Rappaport1999; Sosis Reference Sosis2011).
Second, the complex adaptive systems approach exposes the mechanisms by which religious systems achieve extensive cooperation and coordination, as observed experimentally and ethnographically (e.g., McKay et al. Reference McKay, Harold and Whitehouse2013; Sosis & Ruffle Reference Sosis and Ruffle2003; Xygalatas Reference Xygalatas2013). One such mechanism is religious signaling systems: religious activities are costly and thus serve as honest signals that enable and sustain trust, allowing groups to cooperate and coordinate socially (Irons Reference Irons and Nesse2001). In other words, by performing religious activities, adherents reinforce cooperative norms and signal their commitments to the group, which in turn provides the necessary levels of trust to overcome collective action problems and to maintain group-level traits. However, signaling theory advances Smaldino's argument on other fronts as well. Because signaling theory recognizes that systems can remain stable despite some deceptive signalers (Johnstone Reference Johnstone, Krebs and Davies1997), it anticipates the inherent variation within and across religious communities that Smaldino presumes (Wildman & Sosis Reference Wildman and Sosis2011). It also explains why adherents are highly attuned to signaling variations: they carry respective fitness consequences. Finally, given that signals require arenas of display and reception, signaling theory emphasizes the importance of social and cognitive niches created by religious communities (Bulbulia & Sosis Reference Bulbulia and Sosis2011).
Third, the complex systems approach can explain the variation in social structures across religious systems, including religious variations among bands, tribes, chiefdoms, and states. Although religious systems consist of a core set of recurring features, cultural variation arises from how these elements interact within local ecologies to produce specific practices, beliefs, and structures. For example, although many Christian groups maintain an office of ministry, as Smaldino describes, it is hardly a universal or even a common feature of most religious systems. Rather, ministries emerge under specific conditions, such as when groups can benefit from economies of scale (Sosis Reference Sosis2003, p. 115), which are more common in state systems.
In addition to these three advances, the complex systems approach also overcomes several inherent limitations to Smaldino's understanding of religion as a norm-enforcing institution. First, Smaldino situates social norms outside of religious systems, such that religious institutions act on norms that emerge independently, which is unreflective of human history. The systems approach, in contrast, recognizes that religion was not a separate and well-defined arena of social activity for most of human existence. Rather, religious systems permeated all aspects of social life, and thus norms coevolved with the system itself. Second, religious systems not only enforce norms, but they also naturalize them (Rappaport Reference Rappaport1999). Because religion is comprised of cognitive, behavioral, and developmental elements – and regularly activates human senses – it fully engages practitioners, making social norms feel correct and natural. Lastly, although we share Smaldino's concerns about reductionism, it is necessary to recognize that reductionism is nevertheless essential for uncovering the constituents of religion. However, the complex systems approach avoids the pitfalls of reductionism by emphasizing that selection operates on the system itself, not its constituent parts (Sosis Reference Sosis2009).
To conclude, we stress that we are not offering a competing alternative to Smaldino's account, but rather a helpful extension of his approach. Indeed, we are curious to hear from Smaldino whether the complex adaptive systems approach can complement the valuable extensions to cultural evolutionary theory that he has offered in the target article.
The target article is an important contribution to the study of cultural evolution and an impressive account of the emergence of group-level traits. In Smaldino's view, norm-enforcing institutions and cultural narratives are necessary for maintaining suites of cultural traits, such as organizational patterns, behavioral norms, and cooperative decision-making heuristics. If these traits are maintained over time, they will potentially contribute to the emergence of group-level traits. These are the phenotypic effects of social organization and interdependent collaborations that are made possible only when individuals with differentiated roles are structurally cooperative and socially coordinated. Furthermore, because religion is one of the most effective mechanisms for transmitting whole suites of cultural traits, such as hierarchies that reinforce the group's social organization, it is one of the most important constituents of traits at the group level.
We are in general agreement with Smaldino's account, but we think he has overlooked two crucial points about religion: its unique role in stabilizing prosocial norms and its distinct effectiveness at transmitting suites of cultural traits. Approaching religion as an institution, as Smaldino does, can lead to worthwhile insights about the social structures that support religion and the function of religion as a cultural organization. However, analyzing religions as complex systems more accurately reveals the structures that maintain religions, as well as the traits that emerge from them. Religious systems consist of core interdependent features, such as rituals, supernatural agent beliefs, and myths, which evolved independently but at some point in human history began to co-occur and coevolve regularly and cross-culturally (Alcorta & Sosis Reference Alcorta and Sosis2005; Purzycki & Sosis Reference Purzycki, Sosis, Voland and Schiefenhovel2009; Sosis Reference Sosis2009). As anthropologists observe, elements of religious systems interact in complex ways, resulting in emergent properties (e.g., Geertz Reference Geertz1973) and creating communities with shared customs, cognitive schemas, historical memories, and identities.
Although we are critical of Smaldino's characterization of religion as a norm-enforcing institution, we believe that an adaptive systems approach is consistent with his argument for the emergence of group-level traits and provides various explanatory advances to his conception of religion. We address each of these advantages in what follows. In doing so, we hope to show that, from a cultural evolutionary perspective, religion is better conceived as a complex adaptive system rather than a norm-enforcing institution.
First, understanding religion as a complex adaptive system clarifies how religions succeed at transmitting suites of cultural behaviors while concurrently adapting to varying socioenvironmental conditions. Religious systems achieve this apparent opposition by maintaining hierarchies of religious discourse, in which adherents focus on core statements of belief that remain unchanged, even as interpretations of those statements change over time. Accordingly, adherents typically accept novel interpretations of fundamental postulates as being reifications of eternal or personally relevant truths, while taking little notice of the modifications to religious rules and social norms with each generation (Rappaport Reference Rappaport1999; Sosis Reference Sosis2011).
Second, the complex adaptive systems approach exposes the mechanisms by which religious systems achieve extensive cooperation and coordination, as observed experimentally and ethnographically (e.g., McKay et al. Reference McKay, Harold and Whitehouse2013; Sosis & Ruffle Reference Sosis and Ruffle2003; Xygalatas Reference Xygalatas2013). One such mechanism is religious signaling systems: religious activities are costly and thus serve as honest signals that enable and sustain trust, allowing groups to cooperate and coordinate socially (Irons Reference Irons and Nesse2001). In other words, by performing religious activities, adherents reinforce cooperative norms and signal their commitments to the group, which in turn provides the necessary levels of trust to overcome collective action problems and to maintain group-level traits. However, signaling theory advances Smaldino's argument on other fronts as well. Because signaling theory recognizes that systems can remain stable despite some deceptive signalers (Johnstone Reference Johnstone, Krebs and Davies1997), it anticipates the inherent variation within and across religious communities that Smaldino presumes (Wildman & Sosis Reference Wildman and Sosis2011). It also explains why adherents are highly attuned to signaling variations: they carry respective fitness consequences. Finally, given that signals require arenas of display and reception, signaling theory emphasizes the importance of social and cognitive niches created by religious communities (Bulbulia & Sosis Reference Bulbulia and Sosis2011).
Third, the complex systems approach can explain the variation in social structures across religious systems, including religious variations among bands, tribes, chiefdoms, and states. Although religious systems consist of a core set of recurring features, cultural variation arises from how these elements interact within local ecologies to produce specific practices, beliefs, and structures. For example, although many Christian groups maintain an office of ministry, as Smaldino describes, it is hardly a universal or even a common feature of most religious systems. Rather, ministries emerge under specific conditions, such as when groups can benefit from economies of scale (Sosis Reference Sosis2003, p. 115), which are more common in state systems.
In addition to these three advances, the complex systems approach also overcomes several inherent limitations to Smaldino's understanding of religion as a norm-enforcing institution. First, Smaldino situates social norms outside of religious systems, such that religious institutions act on norms that emerge independently, which is unreflective of human history. The systems approach, in contrast, recognizes that religion was not a separate and well-defined arena of social activity for most of human existence. Rather, religious systems permeated all aspects of social life, and thus norms coevolved with the system itself. Second, religious systems not only enforce norms, but they also naturalize them (Rappaport Reference Rappaport1999). Because religion is comprised of cognitive, behavioral, and developmental elements – and regularly activates human senses – it fully engages practitioners, making social norms feel correct and natural. Lastly, although we share Smaldino's concerns about reductionism, it is necessary to recognize that reductionism is nevertheless essential for uncovering the constituents of religion. However, the complex systems approach avoids the pitfalls of reductionism by emphasizing that selection operates on the system itself, not its constituent parts (Sosis Reference Sosis2009).
To conclude, we stress that we are not offering a competing alternative to Smaldino's account, but rather a helpful extension of his approach. Indeed, we are curious to hear from Smaldino whether the complex adaptive systems approach can complement the valuable extensions to cultural evolutionary theory that he has offered in the target article.