By-product Accounts of Religion

The By-product Hypothesis

By-product accounts, sometimes referred to as cognitive by-product theories, represent a prominent theoretical framework within the evolutionary study of religion. Unlike adaptationist accounts, which posit that religion evolved as a direct solution to recurrent adaptive problems (e.g., promoting cooperation, reducing anxiety), by-product theories argue that religion arises from the routine operation of cognitive systems that evolved for more general purposes, such as understanding the natural world, navigating social interactions, or detecting threats. These theories suggest that while religion may have subsequent adaptive consequences, its initial emergence is best understood as a non-adaptive side effect.

Key proponents of this view include Pascal Boyer, Scott Atran, and Ilkka Pyysiäinen, who have independently and collaboratively developed detailed models of the cognitive architecture underlying religious phenomena. Their work emphasizes the universality of certain cognitive biases and predispositions that, when combined, create fertile ground for the generation and transmission of religious concepts.

Core Cognitive Mechanisms

Several cognitive mechanisms are frequently implicated in by-product accounts of religion:

Hyperactive Agency Detection Device (HADD)

Humans possess a strong tendency to detect agents, particularly animate ones, even in ambiguous stimuli (Guthrie, 1993; Barrett, 2000). This Hyperactive Agency Detection Device (HADD) is thought to be an adaptive mechanism for survival, as it is less costly to infer the presence of a predator or competitor when none exists than to fail to detect a real one. By-product theorists argue that HADD, operating in contexts where natural causes are not immediately apparent, leads individuals to attribute events like storms, illness, or good fortune to the actions of unseen agents, such as gods, spirits, or ancestors. This cognitive bias provides a foundational element for supernatural belief systems.

Theory of Mind (ToM)

Theory of Mind, or mind-reading, is the capacity to attribute mental states—beliefs, desires, intentions—to oneself and others. This ability is crucial for complex social interaction and cooperation. In the context of religion, ToM allows individuals to conceptualize supernatural agents as having minds, intentions, and desires similar to humans (Boyer, 2001). This enables believers to engage in reciprocal relationships with deities, pray to them, and infer their motivations, thereby making supernatural agents psychologically salient and relatable.

Minimally Counterintuitive (MCI) Concepts

Boyer (2001) posits that religious concepts are often “minimally counterintuitive.” These concepts violate a small number of intuitive ontological expectations (e.g., a person who can fly, a rock that can think) while retaining most intuitive properties (e.g., a flying person still has a body, a thinking rock is still solid). Research suggests that MCI concepts are particularly memorable and transmissible across individuals and generations compared to entirely intuitive or entirely counterintuitive concepts. This cognitive sweet spot facilitates the spread and retention of religious narratives and beliefs.

Intuitive Physics and Biology

Humans possess intuitive understandings of how the physical world operates (e.g., objects fall, cannot pass through each other) and how living things function (e.g., birth, growth, death). Religious concepts often play on these intuitive expectations by introducing violations. For example, a ghost might pass through walls (violating intuitive physics), or a god might be immortal (violating intuitive biology). These violations, when combined with agency detection and ToM, contribute to the compelling nature of supernatural narratives.

The Emergence of Religious Systems

According to by-product accounts, these cognitive mechanisms, operating in concert, predispose humans to generate and accept religious ideas. For example, a sudden, unexplained illness might activate HADD, leading to the inference of an unseen agent. ToM allows this agent to be endowed with intentions (e.g., punishing for a transgression). The concept of this agent might then become minimally counterintuitive (e.g., an invisible, immortal ancestor spirit). As these concepts are shared and elaborated within a community, they can coalesce into complex religious systems, complete with rituals, moral codes, and explanations for life's mysteries.

Boyer (2001) emphasizes that religion is not a single phenomenon but a collection of distinct cognitive systems (e.g., ritual cognition, moral cognition, supernatural agent cognition) that become integrated. Atran (2002) similarly highlights the role of existential anxieties (e.g., fear of death, uncertainty) in providing a motivational context where these cognitive predispositions are most likely to be activated and sustained. Religion, in this view, offers compelling, albeit non-verifiable, explanations and reassurances by leveraging pre-existing cognitive biases.

Evidence and Critiques

Empirical support for by-product accounts comes from studies in cognitive psychology, developmental psychology, and anthropology. For instance, research on children's developing understanding of minds and agents shows early predispositions for animism and teleological reasoning, even in secular environments (Kelemen, 2004). Cross-cultural studies document the widespread presence of MCI concepts in folklore and religious traditions. Neuroimaging studies have also explored the neural correlates of religious experience, often finding activation in brain regions associated with social cognition, emotion, and reward, consistent with the recruitment of general cognitive systems rather than a dedicated “religion module.”

Despite their explanatory power, by-product accounts face some critiques. One common criticism is that while they explain the origins and form of religious concepts, they may not fully account for the persistence and intensity of religious commitment, particularly the costly sacrifices and group cohesion often associated with religion (Sosis, 2004). Some argue that the adaptive benefits of religion, such as promoting large-scale cooperation or reducing stress, are too significant to be considered mere by-products and suggest that natural selection may have subsequently favored religious behaviors or the cognitive predispositions that facilitate them. This leads to a debate about whether religion is primarily a by-product that then acquires adaptive functions, or whether it contains elements that were directly selected for their adaptive value. However, proponents of by-product accounts often respond by acknowledging that while the initial cognitive roots are by-products, cultural evolution and gene-culture co-evolution can subsequently shape and stabilize religious practices due to their emergent social functions. The distinction between the origin of a trait and its later maintenance or adaptive consequences remains a central point of discussion in the evolutionary study of religion. The by-product framework continues to offer a robust explanation for the cognitive foundations upon which religious systems are built.