Proximity, Connectivity, Trust - The magical elixir

From Friends of a Certain Age by Alex Williams.

Discussing the making of new friends as one ages.

As external conditions change, it becomes tougher to meet the three conditions that sociologists since the 1950s have considered crucial to making close friends: proximity; repeated, unplanned interactions; and a setting that encourages people to let their guard down and confide in each other

Never heard of those as the three conditions before but it makes logical sense. Also sounds like the preconditions for meme exchange as well as creativity. Also would support the sense of history accelerating. If you are a hunter-gather society, hardly any of those conditions are ever met. As communal living becomes more dense through agriculture and then hamlets, villages, towns, all three conditions can be met more often. People may or may not end up with more friends but there is a greater and greater capacity for meme exchange and serendipitous insight leading to innovation.

The critical item is the last one. In hetergenous society where people increasingly have the opportunity to live self-constructed lives in the midst of high density (i.e. are able to effectively isolate themselves from that with which they do not wish to engage), how do you encourage the creation of trust. Trust seems to me to be the linchpin for experimentation.