Persistent and self-perpetuating political differences between neighbouring communities

The branch of social science known as “legacy studies†has identified the stubborn persistence of political differences, such as levels of prejudice and trust, even between communities that are geographically proximate and otherwise largely similar. The theoretical focus of this literature has largely been on establishing the origin of political divergence. I add instead to theories explaining why such differences manage to persist across time, focusing explicitly on how neighbouring communities with political differences can, under certain circumstances, neither influence nor be influenced by each other. Using a series of simple evolutionary games, I demonstrate that differences can persist so long as intra-community interactions are sufficiently more likely than cross-community interactions. These conditions remain substantively easy to meet across a variety of basic game designs, providing further theoretical basis for the empirical findings of legacy studies.