People don't like to hear it, but a high-trust society is enabled by homogeneity.
Look at Japan's demographics, and opposition to foreign religions, languages, etc.
They don't allow "the world" to recreate itself inside them, and the conflict and distrust (Bowling Alone, Robert Putnam) that that brings.
This is probably a just-so story. Australia is, by the numbers, a high-trust country, and is more diverse than Canada. Both are higher-trust than Japan. Contrary to your claim here, Japan and the US have in fact very similar surveyed levels of trust. What seems actually to be the case is that remarkably high-trust countries, surveyed at, I don't know, several SD above the mean, are rare. Several of them happen to be Nordic, and people extrapolate from there.
I'm sure being ethnically homogenous does smooth things over for Norway. But so does being small and galactically wealthy from extractive industry.
Yes though increase in diversity brings higher demand for authority because it seems to be the only thing that can bring order. Some would call Singapore "authoritarian" (how compatible is it with "Democracy" of the West? Or post-Imperial Japan for that matter -- the main topic here). They invest energy into micromanaging it.[1]
There was a lot of racial tension[2] in Singapore before Lee Kuan Yew straightened them out. Mandates on what languages to use for what ethnicities, with English being the main language, seems to have worked.
As well as a racial quota system to prevent natural self-sorting into ethnic groups, and to enforce integration.
"To prevent conflicts and ethnic isolation (Singapore is the safest city in the world according to Gallup) ethnic quotas are mandatory.The distribution of public housing is carried out based on these quotas and it is impossible to find a block of apartments in which the percentage of Chinese, Indians and Malay people gives preference to one of the groups (with regard to the country’s population). And since the construction and ownership of the property are strictly regulated, given the lack of space on the island, it is extremely hard to escape the system. These quotas are also applied within the administration itself, in businesses and even in some activities such as leisure.To date, the system has been a success that has almost prevented any sign of segregation. However, the model depends on a system of surveillance, punishment and repression, which feels somewhat Orwellian, but without which, its implementation would not be feasible. This is, paradoxically, a society that voluntarily relinquishes certain freedoms related to the way in which citizens interact with one another, in order to guarantee their coexistence."[3]
Difficult to say probably the latter considering the previous cases of racial tensions in Singapore but if you want a non-authoritarian example I think Canada is a good one.
Like it or not, racial tensions fuel a lot of conflict inside nations. America itself has had a lot of racial tension based conflict in its short lifespan than many other countries much older than it. I'm not condoning it of course, just explaining it.
>I hope you don't mean racial homogeneity, because that would be a load of _equine excrement_
I'd argue that Mumbai/India or Lagos/Nigeria are overwhelmingly racially homogeneous. So there must be some additional factor beyond racial homogeneity.
Only if you see "races" as the American-style social construct and not as people in India and Africa see it, which is at a tribal level. I had an hour-long discussion with a Ugandan once that explained to me the major tribes in Uganda, and he says that anyone can tell the tribes apart just by look and dialect. A European looks at Lagos and sees "Nigerians", a Nigerian looks at Lagos and sees Yoruba, Igbo, etc. The Indians also have a brutal caste system and thousands of sub-dialects originating from provincial clan systems and would never call any of their major cities "homogeneous".
Europeans also had a lot more tribal-based racism in the past; southern vs. northern Italians, Scottish vs. Welsh, even sub-clans inside both of those nations, etc.
Look at Japan's demographics, and opposition to foreign religions, languages, etc. They don't allow "the world" to recreate itself inside them, and the conflict and distrust (Bowling Alone, Robert Putnam) that that brings.