it seems that high-trust groups are those that have somewhat homogeneous culture, and strong extended-family and local ties. In other words, a lot of social enforcement of norms, with less legible codified behavioral limits.
There can be people who are simultaneously members of high-trust groups and communities, AND low-trust societies and groups.
The important related question, as you say, can this be arrested or mitigated as a group gets larger and more diverse, so social/cultural norm enforcement via “what will grandma think?” becomes infeasible.
Speculation only!
it seems that high-trust groups are those that have somewhat homogeneous culture, and strong extended-family and local ties. In other words, a lot of social enforcement of norms, with less legible codified behavioral limits.
There can be people who are simultaneously members of high-trust groups and communities, AND low-trust societies and groups.
The important related question, as you say, can this be arrested or mitigated as a group gets larger and more diverse, so social/cultural norm enforcement via “what will grandma think?” becomes infeasible.