I think we, as Humana, mentally survive a lot better in smaller local groups. Once a certain population density hits, it seens things go wrong much more quickly.
While it’s likely we’re best adapted psychologically for small groups, how much of that is universally relevant in a modern context is unclear. A lot of people have left small towns in recent decades due to their often-gossipy social dynamics and the mental toll that can take… speaking from experience, coming from that being “just a number” in a city can be much needed relief.
Small local groups can exist in cities, too. That’s not too far off from the concept of a neighborhood, something that is being lost in the sprawl of suburbia and commute-by-car.