I had a request to report on the CFI panel on the evolutionary origins of religious belief. I didn’t take notes, but I’ll try to recall some of the highlights. These are not my views, I’m just passing along what was discussed.
Randy Thornhill, Professor of Biology at the University of New Mexico, presented his “parasite-stress theory,” which essentially argues that people’s political and religious temperament is largely shaped by subconscious biological processes in response to their perceived risk of infection. In our evolutionary past, disease was a massive factor, maybe the primary factor, driving our evolution. In tribal societies, you’ve probably already been exposed to all the germs of everyone in your tribe, so the real risk of deadly contagion comes from outsiders. In this environment, hostility to outsiders can be a strong survival trait, but too much hostility to outsiders can also hinder your survival, as it cuts you off from trade, possible mates, etc. So hostility to outsiders has to be carefully calibrated according to the risk of infection. Religion, in his view, is a powerful force for strengthening in-group solidarity while increasing out-group hostility, and would therefore be expected to evolve in tandem with high levels of parasite-stress. The theory goes that the more stressed you are about possible infection, the more your biology responds to elevate your hostility to outsiders. Thornhill presented graph after graph demonstrating this correlation (though of course establishing causation from correlation is extremely problematic). Conservatism is generally characterized by higher antipathy toward outsiders. The more disease there is in any given country, the more Conservative that country is likely to be. The more disease there is in a given U.S. state, the more Conservative that state is likely to be. Individuals who are more concerned about disease are more likely to be Conservative. Most striking of all, pregnant women in their first trimester (when the immune system is suppressed so as not to reject the fetus) are markedly more Conservative on issues such as immigration than they are either before pregnancy or after the first trimester. Thornhill also concludes that the Liberal movements of the 1960s in Western countries — civil rights, the women’s movement, the sexual revolution — were the result of decreased parasite-stress, which was brought about by innovations such as chlorinated/fluoridated water several decades prior. (In countries without such technological innovations, no comparable social revolutions occurred.)
David Sloan Wilson, Professor of Biology at SUNY Binghamton, began with a sort of survey of the various evolutionary models to explain religion. These fall into adaptive and non-adaptive categories. Non-adaptive explanations are ones such as that metaphysical belief systems really have no impact on an organism’s survivability, so religion spreads and changes more or less arbitrarily, similar to genetic drift. It might also be the case that religion is a non-adaptive necessary byproduct of a linked adaptive trait — for example, we evolved to be really smart, which helped us survive, but one consequence of being really smart was that we could worry about our own mortality, which created the impetus for not-terribly-constructive religious rituals. Another non-adaptive explanation would be that religion was once adaptive, given the drastically different environment in which we evolved (tribal societies on the African savannah) but is no longer so. (Wilson compared this to our eating habits. We’re biologically programmed to stuff ourselves with as much fat and sugar as we can lay our hands on, which is a perfectly rational survival strategy when you’re at constant risk of starvation, but which becomes extremely maladaptive when you continually have more food available than you need.) There are also the adaptive explanations, which he favors, i.e. that religion makes an organism more likely to survive, either at the group level (religious communities have more solidarity) or at the level of the individual (religious people are less stressed). This is in marked contrast to the adaptive explanation put forth by Dawkins and Dennett, which states that religion operates like a virus, spreading itself through populations, constantly mutating into ever more powerful and seductive narratives, aiding the survival of nobody but the ideas themselves. (For example, the Greek/early Jewish concept of the afterlife — a dismal place of perpetual boredom and emptiness — mutated into the more attractive notion of eternal bliss for you and your friends along with eternal torment for your enemies, and that second narrative therefore thrived while the first largely died out.) Wilson talked about the importance for human beings of having meaningful narratives for their lives — which religion provides. (Though there are equally potent non-religious sources of meaningful narratives.) He described an experiment in which one group of students was regularly assigned to write essays about the things that mattered most to them while another was tasked to write about abstract or trivial topics. At the end of the semester, the first group was actually measurably healthier than the second. Wilson also does research in which college students are asked to wear a device that beeps at them eight times a day. Each time the device beeps, the students are supposed to fill out a quick questionnaire about what they’re doing and how they’re feeling. Wilson was looking specifically at the differences between adherents of notably Liberal religions (Unitarian) versus notably Conservative religions (Seventh Day Adventist). One of the findings was that students belonging to Liberal religions were more stressed generally, perhaps because they experience more worry and anxiety around making decisions, whereas members of Conservative religions were more likely to apply a simple set of black-and-white rules, obviating the need to stress about making tough calls. Conversely, the study also found that Liberals spend about twice as much time alone, and are comfortable doing so, whereas Conservatives experience sharply rising levels of anxiety when separated from their social group.
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