UCLA Library

Religion, a shared social system that connects people with a supernatural power, exists in human populations worldwide. Scientists have long debated whether religion is a cultural or evolutionary phenomenon; that is, whether religion is a learned set of values, beliefs, and behaviors, or instead the result of gene variants that have increased in frequency over time. In this paper, I argue that natural selection, the process by which the frequency of certain genes increases over generations due to their reproductive benefit, has played a role in the persistence of religion. I begin by providing background on the definitions of religion, biological evolution, and adaptation, which are necessary to clarify before analyzing the role of biological evolution and adaptivity in religion. I then explain and provide evidence for how religion meets the three conditions of natural selection. Finally, I present multiple adaptive hypotheses to explain how religion might increase fitness. This work clarifies scientific understanding of how natural selection impacts religion and expands on existing adaptive hypotheses that explain how religion might increase biological fitness.