"We applaud Michele J Gelfand and colleagues on their analysis of cultural tightness–looseness in relation to COVID-19.1 Their work provides an informative and, given the reported effect sizes, compelling demonstration that countries with greater cultural tightness have fewer COVID-19 cases and deaths than culturally looser countries do. The authors also propose an interesting corollary to their results, stating that: “The results suggest that tightening social norms might confer an evolutionary advantage in times of collective threat.” and that “Social norm interventions will be critical for helping groups to tighten norms […] to deal with future collective threats.”. These statements raise an intriguing and important possibility. Cultural tightness might offer a compelling explanation for variations in, and be a potential vector for influencing, national action on another collective threat: national climate change mitigation. We tested this possibility..."

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