Why Rain Rituals Survive in Some Climates but Not Others
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- José-Antonio Espín-Sánchez of Yale University co-authored a study, published in the Quarterly Journal of Economics, comparing customs of 1,290 ethnic groups with local climate data and finding rain-making rituals present in 44% of groups where rain probability rises with successive dry days versus 30% where it does not.
- The research traces why rituals like Murcia, Spain's seven-century-old Catholic special prayers and dragon invocations in China around AD 1000 appear to work — in those climates, the longer a drought lasts, the more likely rain becomes.
- Simon Papalexiou at the Hamburg University of Technology, who was not involved in the study, called the central statistical idea 'plausible' and identified two mechanisms: true duration dependence, and seasonal anticipation, where rituals happen near the end of the dry season when rain would soon arrive anyway.
- Espín-Sánchez built a mathematical model showing that priests who time rituals just before rains return are more likely to keep their jobs, and that those religions or rituals are more likely to survive.
- Kevin Hong at the University of Macau, who published a separate study on Chinese rain-making emphasizing confirmation bias, said Espín-Sánchez's results suggest he may have 'underestimated the possibility that these rituals may be, in a sense, objectively effective.'
- Espín-Sánchez argued the model could extend to rituals for other hardships like epidemics or diseases that are 'sufficiently complex that you cannot really see that it's just going to go away on its own, but sufficiently simple that doing something looks like you're curing the illness.'
Why it matters: The study offers a rare testable mechanism for why religious rituals cluster in particular environments: in climates where dry spells end predictably, priests who time ceremonies just before the rain are rewarded with credibility, and their rituals survive. For scholars of religion and behavioral economics, it bridges two literatures that rarely meet, and Espín-Sánchez suggests the same framework could explain the persistence of healing rituals around self-resolving illnesses.
