The majority of people living on this planet are not weird. No, it’s you reading this (and me, writing this) who are weird. Or I should say, WEIRD: that is, Western, educated, industrialised, rich, democratic.

It’s a nice, smart pun. It’s also entirely in tune with our current trends towards unearthing various kinds of “privilege”. But according to the academic who coined it, Harvard professor Joseph Henrich, understanding WEIRDness could mean a huge re-evaluation of what we think “human nature” is.

In his new book, The Weirdest People in the World: How the West Became Psychologically Peculiar and Particularly Prosperous, Henrich erects a massive theory (backed up by bedazzling amounts of evidence) to explain how partial and specific Western civilisation is. And how it should sit on a planet of cultures which often reject its views.

His story begins in the psychology labs of lush and wealthy American universities. About 10 years ago, the penny dropped with Henrich and others that something was fundamentally wrong with their research.

Grand pronouncements were being made about human “universals”, rooted in our evolved nature. Turns out, however, that 96% of the study participants generating these results were, well, WEIRD – drawn from undergrads or postgrads, or the children of academics, in American campus zones. How humanly universal could those results really be?

As an anthropologist, Henrich was a regular surveyor of non-Western cultures across the world, modern and indigenous. He concluded that we WEIRDos were outliers in a world defined by much older forms of social relations – essentially based on kin and extended families.

The WEIRD are individualist, think analytically, believe in free will, take personal responsibility, experience guilt when they misbehave, and believe nepotism should be strongly discouraged, even outlawed.

The non-weird (okay, we’ll drop the caps for now) have a stronger identification with family, tribe, clan and ethnicity; use their minds in a more “holistic” way; admit responsibility for what’s done by their “group” (and will punish those who dishonour it); experience shame (not guilt) when misbehaving; and find nothing odd about nepotism.

There are some elegant experiments behind this – say, the difference between analytical and holistic thinking. The former puts people or objects into distinct categories, gives them properties. The latter prioritises context, interaction and relationships. “If person A is yelling at person B, an analytical thinker might infer that person A is an angry person,” says Henrich, “while a holistic thinker worries about the relationship between persons A and B.”

Another nice one is called the Triad Task. “Subjects are shown three images – say, a rabbit, a carrot, and a cat,” observes The Atlantic magazine. “The goal is to match a ‘target object’ – the rabbit – with a second object.

A person who matches the rabbit with the cat classifies: the rabbit and the cat are animals. A person who matches the rabbit with the carrot looks for relationships between the objects: the rabbit eats the carrot.”

Again, Henrich exhaustively shows how consistently these tests around the analytical and the relationship-based are playing differently between weird and non-weird cultures.

Anyone who knows anyone from a strong Buddhist, Confucian or Muslim background will hardly be surprised that Henrich and colleagues had found these cultural distinctions (though we mustn’t be simplistic about the way religious and spiritual frameworks inform the projects of contemporary governments in Asia, the Middle East and Africa).

What is intriguing about Henrich’s thesis is his explanation for why our Western model should have become so dominant. And also what might have been lost, as we steadily advanced our mode of being into other cultures.

For Henrich, the West rose because the Roman Catholic Church, in the 11th century, mounted an attack on closely-intermarried, deeply-connected tribal households. Henrich calls it the “Marriage and Family Program” (MFP). This primarily outlawed cousin marriages, pushing any legitimate union out to the sixth relation. It also discouraged adoption and arranged marriages.

The effect of this was to break up the thick layers of duties and obligations in these tribes, and send Christians spiralling elsewhere to find their Christian partners. The MFP also introduced the idea that previously inheritable resources didn’t have to pass down to clan or tribal members – but could potentially go anywhere. Indeed, preferably, into the coffers of the Church itself.

This is an interesting claim. It’s a truism that the Reformation intensified individualism: printed bibles coming into the hands of congregants, who were then free to make their own readings of scripture. And increasingly, other existential choices.

Henrich claims that this de-tribalising process started significantly earlier. But he is oddly blurry about why the Catholic Church would have persisted, decade after decade, with such an unpopular policy. More scholarship is required.

You will also know your own (or others’) family feuds – over property, authority, duty. This can produce mini-mafias and petty dynasties. But as proved by Covid, these thick kin relations can also drive a near-miraculous flowering of mutual aid and support at a moment of crisis.

Musing on the fieldwork he did in Fiji, Henrich talks of “the kind of comfort that comes from the warm embrace of knowing you are at the centre of a tight web of relations”. “They are tied to you in a deep way and they will be tied to your children … WEIRDness undermines this.”

Tribes see themselves as “links in a chain connecting past to future, with a sense of continuity”, notes Henrich. “Then you get Westerners who are like, ‘I’m an individual ape on a pale blue dot in the middle of a giant black space’ and ‘what does it all mean?’”

That’ll be me, then. It’s tempting to be philosophically and culturally curious.

We’re the WEIRD ones, from the perspective of the rest of the planet: Henrich’s excellent, powerful book knocks that point home. But I’m afraid this egoistic, analytic, restless, guilt-ridden ape will not easily be reprogrammed. Suggestions – therapies, encounters, substances – on a postcard, please. And the right kind of weird, if you don’t mind.

The Weirdest People in the World: How the West Became Psychologically Peculiar and Particularly Prosperous, by Joseph Henrich, is on Penguin Books.