In the early 1990s, a political economist named Laurence Iannaccone claimed that seemingly arbitrary demands and restrictions, like going without electricity (the Amish) or abstaining from caffeine (Mormons), can actually make a group stronger. He was trying to explain religious affiliation from a rational-choice perspective: in a marketplace of religious options, why would some people choose religions that make serious demands on their members, when more easygoing, low-investment churches were ”“ literally ”“ right around the corner? Weren’t the warmer and fuzzier churches destined to win out in fair, free-market competition?
According to Iannaccone, no. He claimed that churches that demanded real sacrifice of their members were automatically stronger, since they had built-in tools to eliminate people with weaker commitments. Think about it: if your church says that you have to tithe 10% of your income, arrive on time each Sunday without fail, and agree to believe seemingly crazy things, you’re only going to stick around if you’re really sure you want to. Those who aren’t totally committed will sneak out the back door before the collection plate even gets passed around.
And when a community only retains the most committed followers, it has a much stronger core than a community with laxer membership requirements. Members receive more valuable benefits, in the form of social support and community, than members of other communities, because the social fabric is composed of people who have demonstrated that they’re totally committed to being there. This muscular social fabric, in turn, attracts more members, who are drawn to the benefits of a strong community ”“ leading to growth for groups with strict membership requirements.