Commitment through Sacrifice: How Longer Ramadan Fasting Strengthens Religiosity and Political Islam
利用斋月禁食时长因纬度和年份变化的自然实验，发现禁食时间每增加半小时，土耳其伊斯兰政党得票率上升11%，并增加古兰经课程参与率，表明牺牲通过承诺机制强化宗教信仰和政治支持。
Religions seem to defy the law-of-demand, which suggests that all else equal, an increase in the cost of an activity will induce individuals to decrease the resources they spend on that activity. Rather than weakening religious organizations, evidence shows that the sacrifices exacted by religious practices are positively associated with the success of those organizations. We present the first strong evidence that this association is neither spurious nor endogenous. We use a natural experiment that rests on a peculiar time-shifting feature of Ramadan that makes the fasting duration—our measure of sacrifice—vary not just by latitude but from year-to-year. We find that a half-hour increase in fasting time during the median Ramadan day increases the vote shares of Islamist political parties by 11 percent in Turkey’s parliamentary elections between 1973 and 2018, and results in one additional attendee per 1,000 inhabitants for voluntary Quran courses. We further investigate two mechanisms, screening and commitment, that could explain the effects we find. By testing their divergent implications, we infer that commitment is the mechanism triggered by sacrifice, which drives up the intensity of religious beliefs and participation that in turn bolster the success of religious organizations.