When populations are homogenous, people see that other people are mostly like them – ethnically, culturally, socioeconomically, etc. This boosts trust broadly, which makes everyone more open to progressive social policies and safety nets.

When populations are diverse, people are more visibly different, at least on the surface, which leads to othering, dampens trust, and leads to more protectionist, socially conservative policies.

This is an oversimplification, and happens only in our subconscious, but there may still be a nugget of truth to it. It might be one reason that Scandinavian countries have long been so open, progressive, and even socialist: their populations are extremely homogenous. North America and western Europe are historically diverse, on the other hand, now more than ever, which has coincided with populist waves of nationalism, isolationism, and xenophobia.

Stephan Shakespeare, co-founder of pollster YouGov, has a famously evocative metaphor:

We are either “drawbridge up” or “drawbridge down.” Are you someone who feels your life is being encroached upon by criminals, gypsies, spongers, asylum-seekers, Brussels bureaucrats? Do you think the bad things will all go away if we lock the doors? Or do you think it’s a big beautiful world out there, full of good people, if only we could all open our arms and embrace each other?

Whichever you feel personally, this begs the question: why do you feel that way? Homogeneity or diversity in your immediate surroundings could be one answer.

Subtle, powerful point that I hadn’t fully appreciated until now. Thanks to Jonathan Haidt.