I have read that people are capable of maintaining about 150 relationships with other humans. This therefore seems like a reasonable maximum size for human organizations — churches, businesses, towns, etc. For maximum trustiness, perhaps all humans should live in communities of 150, which could then reasonably organize for their own self-interest, well-being and happiness.
But humans seem to desire to live in slightly bigger communities, and to network between much larger groups of people. So how to manage it?
First, each community of 150 could appoint one person to go to a meta-council of 150 people from 150 other communities.
That would be kind of pressing our meta-council members, but they would probably be able to maintain close relationships with enough of their constituents and enough of their fellow meta-council members to effectively represent their areas and cooperate with each other for regional benefits. This allows for the governing of 22,500 people, or a small city. (For comparison, the island of Palau has about 21,000 people; a few other small island nations have similar population sizes.)
The meta-meta level seems difficult to achieve, as we’re already asking people to effectively have 300 contacts, and anyone appointed to a meta-meta council would really have their primary interests back in their 150 member community, and so would do a bad job of representing the interests of everyone else in their 22,500 meta-community. (This is precisely the problem of Congress.)
The meta-meta level might be doable on a basic referendum level–that is, if the meta-meta councilors simply represent the majority views of their meta-regions in a system that does not require them to interact with or convince each other. This would allow for the administration of about 3.4 million people–a large city or small country. (By comparison, Iceland has 330,000 people; Lithuania has 2.9 million, and New Zealand has 4.6 million.)
However, we might be able to organize a few more people into our system by taking advantage of some sort of network effects at the bottom level. Perhaps instead of including all 150 people in our community in a community council, we utilize 150 heads of households (each household can appoint whoever it wants to the council). If we estimate about 4 people per household, then the basic community has 600 people, the meta-community has 90,000, and the meta-meta community has 13.5 million. (Belgium has 11.2 million people.)
Effective, long-term organization beyond this size probably becomes very difficult (unless you are okay with dictatorship, and even that can fail miserably at organizing things).
Predictive value: If my train of thought is correct, communities of <14 million should generally be stable, high-trust, efficient, and effectively democratic in nature. Communities of >14 million should generally be low trust, unstable, inefficient, or undemocratic.
A quick glance at a list of countries by size indicates that there are a bunch of small, poorly-run countries, which may contradict the theory. Perhaps badly run countries break up into pieces until they find an organizational level they can function on.
Here is a list of countries by interpersonal trust. (Unfortunately, this dataset seems to lack many of the tiny countries. Anyone else got a better dataset?) The top scorers–countries where most people reported trusting most of their neighbors, were:
New Zealand: trust level 102.2, population 4.6 mill
Vietnam: trust level 104.1, population 91.5 mill, not democratic
Saudi Arabia: trust level 105.8, population 31.5 mill, not democratic
Switzerland: trust level 107.4, population 8.2 mill
Finland: trust level 117.5, population 5.5 mill
China: trust level 120.9, population 1.4 billion, not democratic
Denmark: trust level 131.9, population 5.7 mill
Sweden: trust level 134.5, population 9.8 mill
Norway: trust level 148, population 5.2 mill
So, it’s a small set of countries and the small ones generally aren’t in the dataset, but the democratic, high-trust countries are all between 4 and 10 million people. The larger high-trust countries are all not democracies.
The worst scorers (countries where fewer than 1 in 10 people said they thought most people were trustworthy):
Trinidad and Tobago: trust level 7.9, population 1.3 mill
Cape Verde: trust level 9, population 500 thousand
Rwanda: trust level 10.2, population 11 mill
Turkey: trust level 10.2, population 78 mill
Botswana: trust level 12.3, population 2 mill
Malawi: trust level 14.9, population 16 mill
Cambodia: trust level 15.6, population 15.4 mill
Indonesia: trust level 16.9, population 255 mill
Brazil: trust level 17.5, population 204.3 mill
Malaysia: trust level 17.7, population 30.6 mill
Looks like unpleasant countries can come in any size.
I’d love it if someone made a scaterplot of size vs. trust, with democracies in blue and non-democracies in red. :D