Cultural Adoption
A culture can grow merely by appealing to and converting outsiders. In practice, cultures with high cultural adoption proliferate over the short term but die quickly over the long run. Why? A common attribute that makes cultures seductive is “easy and forgiving” elements, which in turn contribute to low birth rates.
Strong cultural adoption rates are not as important as one might imagine: Even cultivars with active missionary mandates, like Mormons and Jehovah’s Witnesses, have high birth rates to thank for the lion’s share of their growth. For the most part, religions almost only grow through conversions over very limited temporal and geographic windows. Even when religions do grow rapidly through conversions, they often fail to spread their original culture, instead forming a new cultivar which is a mix of local culture and the new theology.
This is not to say that cultural adoption cannot serve as a major growth driver for a cultivar. Successful proselytization is commonly achieved through harvesting the children of another culture at a very young age in something we will call the “reverse cuckoo strategy”—because they snatch eggs from others’ nests.
Quakers, for example, grew by specializing in educational fields. Shakers gained adherents by specializing in orphanages. Ultimately, however, both Quakers and Shakers began to collapse when government-backed alternatives wiped out their top recruitment channels.
Other top tactics used throughout history by cultivars to grow rapidly through conversions include (in order of descending efficacy):
- Conversion Incentives: Offering tax-advantaged status or highly sought-after jobs only to members of the culture in question can significantly boost conversions. This method was leveraged by both Roman and Islamic empires to significant effect.
(The current university system uses this strategy to convert people by controlling “elite access” in our society and requiring a college degree at one of a few institutions to enter it, then using said institutions to culturally convert people out of more “traditional” birth cultures.)
- Violent/Forced Conversion: Military conquest, followed by intermarriage (in other words, killing the men and marrying the women) and/or state-controlled child-rearing has also been used to boost cultural adherence (as Canada did with some of its native populations through the Canadian Indian residential school system). This type of child conversion is much less effective at wiping out native cultivars than tricking non-members into giving you their kids willingly.
- Missionary Work: By creating a culture-wide expectation that some or all adherents will devote a certain time or amount of their lives to missionary work, as Mormons do, a culture can at least moderately boost cultural adoption rates.*
While the average Mormon missionary baptizes 2.43[[66]**](#_ftn66) people, many of these baptisms are out of convenience (e.g., “You can use our soccer court after you get baptized”)—even though missionaries are technically not supposed to do this.*
More than 50%[[67]](#_ftn67) of those baptized on missions leave the church within a year and within a few years, 75% have left (according to BYU and Reuters,[[68]](#_ftn68) at least). If the church baptized 125,930 people[[69]](#_ftn69) in 2021, total membership was 16,663,663, and the average Mormon lives 85 years; this means the average Mormon converts 0.16 people who stay in the church for more than a few years.
This number feels way off. Our guess is the church chose to include in their statistics anyone who had ever been baptized as a member, so we went to a third-party source to get a different data set. If we use that source, which claims there are 4,400,000[[70]](#_ftn70) active Mormons, then the average Mormon converts 0.6 people in their lifetime. While this is not great, it is at least a viable means of spreading if used in addition to above-repopulation-rate birth rates.
We performed this math to demonstrate that even in best-case scenarios (with a cultivar that both aggressively tries to convert people and is largely viewed favorably), missionary work is only marginally effective and seldom capable of conversion at “above repopulation rate” (e.g., >1 convert per member per lifetime) outside of cases in which the culture controls child-rearing institutions (Quakers and Shakers) and cases in which the culture controls the state apparatus (Roman and Islamic empires).