This article explores under what circumstances a species is more likely to evolve. You need mutation but that’s not enough because a potentially salubrious mutation can be snuffed out by random noise; the monkey who has the mutation making him 1% smarter than his peers may get eaten by a lion before his mutation has a chance to spread through the population. If a species goes off to form little breeding colonies periodically and then reconvenes that’s better. In this case our hypothetical smart monkey can go off and breed a little sub-population of smart monkeys, and when this sub-population starts interacting with the rest of the monkeys they can have more offspring and the whole monkey species will evolve.
What are the analogous rules for cultural evolution? It seems like something analogous is true. It’s not enough that there need to be cultural mutations — say a new way of writing poetry that is kicker or more evocative or more memorable — because this new way can just vanish in the marketplace. The new cultural form needs a protected enclave in which it can thrive and get love, and then it can burst onto the global marketplace. This is probably the function of sub-cultures and fandoms.