#DevTalks: Culture, Psychology and Economic Development

Joseph Henrich is the Ruth Moore Professor of Biological Anthropology in the Department of Human Evolutionary Biology at Harvard University. Dr. Henrich's research deploys evolutionary theory to understand how human psychology gives rise to cultural evolution and how this has shaped our species’ genetic evolution. Using insights generated from this approach, Professor Henrich has explored a variety of topics, including economic decision-making, social norms, fairness, religion, marriage, prestige, cooperation and innovation.

Eliana La Ferrara, Professor of Public Policy at Harvard Kennedy School, moderated a discussion with Prof. Henrich on November 8, 2022 at Harvard Kennedy School.


DISCLAIMER: This webinar transcript was loosely edited and there may be inaccuracies. 

Eliana LaFerrara: Hello, everyone, Welcome to Dev talks. I am Eliana LaFerrara, and I'm a professor of public policy at the Harvard Kennedy School. It is a great pleasure today to be welcoming Dr. Joe Henrich from Harvard University for a session that will largely revolve around his book, titled the weirdest people in the world how the West became psychologically peculiar and particularly prosperous.

Joseph Henrich: Thanks to the Growth Lab for having me and for being flexible on the format. So in the the initial there was going to be more discussion. But one of my goals here, and and why I'm. So excited to be talking to a diverse group with policy interests and interest in economic development is that I come from the field of cultural evolution, which is a a kind of newly emerging discipline, and I think it can provide a valuable framework. But most of you are probably unfamiliar with cultural evolution. So I wanted to do a little bit of groundwork and kind of lay some of that out, so i'll be drawing on both books, and we'll spend some time on the weirdest people in the world. But this book really provides the framework for thinking about culture and cultural evolution one.

Now, I thought, since the group is maybe half economists, I would make this my outcome variable and just start thinking about the things that influence economic growth, and my kind of ah prelude or preamble is going to be based on a new paper where we just try to establish a simple and robust connection between family structures around the world, traditional family structures and economic growth. So i'm, drawing here on a a paper with Duma and Barani, Rod Jonathan Beecham and Jonathan Shilts.

And we're going to argue that we should think about kinship norms as kin based institutions so cult fully transmitted social norms that shape things like marriage, the organization of family. Some societies have clans, kindreds, different marriage systems, and different forms of customary inheritance.

I'll be talking about this more, But the key dimension we want to try to measure is kinship intensity. And this is actually a concept from anthropology. So we're going to combine an economic problem with an idea from anthropology, and see if we can look for a link here.

Ultimately I'll be arguing that economic growth is generated when there's a fit between informal institutions, like kinship and the psychology, that they produce the kinds of social networks they produce in larger scale impersonal institutions, things like democracy or the organization of business firms.

So, as a as an outcome measure as an initial outcome measure, we're going to use this nighttime satellite luminosity which has been widely used. Now it's. Ah, you know, it gives us a fine-grained pixel level measure of economic prosperity that correlates strongly with other measures of economic growth and prosperity, and in the paper I'm. Referring to, we also use regional Gdp measures from genioli, twenty, fourteen, which gives us over one thousand five hundred different regions in eighty four countries, and we perform a bunch of analyses linking these two in the paper.

Now, kinship intensity, As I mentioned many of you. If You're from societies that are Western, educated, industrialized, rich, and democratic. A lot of this talk about kinship may seem strange because those societies are at the extreme end of low kinship intensity where the family has been suppressed and doesn't play an important role in distribution. Consumption networks, all kinds of things like that.

So we're going to measure kinship intensity by looking at the presence of Clans cousin. Marriage rules about post marital residents where you live. After you get married you live near uh the bride's family, or the grooms family. Uh, do you have polygeny? And what kind of inheritance system do you have patrilineal matrilineal inheritance by Testament.

So we're going to measure this kinship intensity from this anthropological data source composed in the nineteen sixty S. Um. Which is going to has a whole bunch of information about kinship, and when I first went to graduate school I was like, Why are anthropologists so obsessed with kinship?

and then I went to do research in the South Pacific, and i'm like Oh, because the people are obsessed with kinship. And so they write about what the people obsess about. And So there's lots of data in the ethnographic atlas on that the year which most of these observations refer to as one thousand nine hundred. So it's going to precede our satellite observations, our nighttime luminosity measures, which are two thousand and ten we're; also going to be drawing this kinship intensity Measure from a a paper by Jonathan Schultz, myself, and others. Actually, it's the same Co. Authors uh that we published in science. So in that sense we're going to tie our hands right. We have to use the exact same measure that we use in the science paper, so we can't kind of fudge around with the index at all.

Ah, and we're also going to take data from genetics. So my colleague, David Reich, who's over in the department of Human Evolutionary biology, has put together the largest data set of human genetic data, and these kinship practices leave an imprint in the genome, which is one way to kind of assess that what these anthropologists report is actually affecting things because it's going to shape the the lengths of runs of homozygosity, both polygeny and cousin marriage and other kinds of endogamous marriage preferences should do that. So we're going to use that, and we're just going to substitute this in sometimes for that.

Okay, So a standard issue economic regression table. Hopefully, at least half of you are familiar with these. I'll just walk you through some of the key insights. So we're trying to predict this pixel level luminosity. So the logarithm of pixel level luminosity we're using this kinship intensity index from the anthropologists in the nineteen sixty s that we've used to assign ethnic groups all around the world a measure of of kinship intensity.

And so, by putting this here and noticing that this is about one, this coefficient. Here we can interpret this as a as a prosperity per capita, so it's luminosity per capita.

So that's that, And then this is our coefficient here. So a one standard deviation increase in kinship, intensity across societies results in a forty percent decrease in luminosity. So if you buy that as a measure of economic prosperity. There's a relationship there now. We estimate a whole bunch of different specifications, different models We always. We put in country fixed effects. So we're comparing only ethnic groups in the same country.

We can't. We control for a whole bunch of the standard geographic controls political hierarchy and malaria index stuff from other other work that could be leading us astray.

And then we take that out. We use the exact same model, and then we stick in our f value, and we're able to show that that gives the same result. And then we do the same thing with our satellite luminosity. We take that out same specification plug in the G, and only regional stuff.

You have to make a few adjustments. But you get basically the same. Answer. So that's that's suggesting that There's this robust linkage there.

There's some details about how we match the ethnographic Atlas that i'm going to pass over for our purposes here. 

Now the other thing we did that helps us, maybe think that this is. There's really something to this: this ancestral kinship intensity affecting contemporary economic outcomes.

We do what's called a spatial regression, discontinuity, analysis. So we look at the borders between our ethnic groups, and we only focus on groups within countries, So there's no country level differences here, and we compare, and we look at what happens when we move from a a population that has a low kinship intensity so small, maybe monogamous nuclear families to a group with clans or something like that, some intensive group.

And what we find that you can see pictured here is that there's a drop in ah in luminosity. So you have less economic prosperity as you move from groups with hot, with low kinship, potentially to high intensity. So that's consistent with the other results.

We can, you know, do the full analysis. And that's the basic answer. We get these coefficients here are just the Ki when you cross that uh the effect there.

Okay. So that suggests that there's a linkage here. Now, why is that the case?

Lots of economists and others have argued that. Well, it has to do with differences in innovation, specialization, political institutions, trade. And so there's a causal relationship there. Potentially. I leave that to other people. I'm. Interested in how these affect this.

So in the weirdest people in the world, I make the case that different kinship norms create an environment that leads to different ways of thinking about the world, and then that leads to more or less innovation, specialization, different functioning, political institutions, and more or less trade.

These can also be seen in social networks. So these have a huge and direct effect on your social networks. And so these two co-evolve.

Where's my arrow? Okay, there it is now. I'm also going to think about where kinship norms come from.

So there's a lot of reason to think ecology matters, and that'll pop up at one point, but I'm. Mostly interested in the historical effect of religions. Religions have been very opinionated about marriage in the family, especially as you move through time over the last few millennium, so we'll get into the Catholic Church. But other religions also have opinion, so we can think about how different religious traditions may have affected things through kinship. Mars.

One of the challenges. If you look across the social science, I think, is how people think about culture.

When I first started in anthropology. Culture felt like this sort of murky thing, that sort of looms almost like a haze around people. It's hard to get, you know my my background is aerospace engineering that I was an engineer for a while before going into this business, and so I want things to be concrete and measurable.

So I found this work by. Ah, yeah, I ended up working closely with Rob Boyd and Pete Richardson, and also there's other work by two biologists, cavali, sports, and feldman. And they said, Well, culture is this stuff that resides in individuals heads, and it gets transmitted from one person to another.

Why, you're growing up, but also why are an adult? So it's about how you learn from people. So you can build models of cultural evolution by understanding how people learn from each other and then cobbling up thinking, Okay, people interact, They learn, they do stuff, they interact again. And how can that get us to explain sociological phenomena, and what we know from a lot of research now is people automatically and unconsciously learn all sorts of things. So they learn motivations, valences, ideas, beliefs, and values. They also learn decision, making biases and heuristics and the kinds of things that directly affect people's decision making.

So culture Here is information stored in people's brains that got there via social learning. And so with that definition, technologies fall into this. Languages fall into this fertility, preferences, or any traits that influence fertility. I'm just throwing those out there, because often some people try to carve those out of culture.

So anything we socially learn from others we acquire while growing up. Of course, institutions are shaped strongly by social wars.

So now, where the evolution comes in, and why, I think that's really important is, How do we decide how people learn from each other?

Well, I mean, when I talk to economic theorists who think about this, they'll just make an assumption or or assume people are rational. What we do in the cultural evolution field is, we recognize that we're a kind of ape, and that natural selection has shaped our minds to be good at learning from others.

So, more than any other species, we're awesome at imitation. We're awesome at inferring the underlying ah motivations and strategies that others have, and we copy those all the time. And outside of conscious awareness we're particularly tuned into copying some kinds of people and not other kinds. So we use cues of shared dialect or prestige to figure out who to pay attention to.

So we can use evolutionary theory and build formal models that tell us what this should look like. And then, of course, we have other features of our evolved psychology that are going to affect behavior, and this is going to be really important for kinship.

Now, the product of this cultural evolution creates things like complex tools, rituals, and practices, but also social norms at institutions as well as languages. And this is the world in which kids are evolved in.

And so the argument that's in the secret of our success is, we have these big brains, and we have a great deal of plasticity, because we need to learn how to navigate the world built by cultural evolution. And of course, cultural evolution has built lots of different worlds, and it's been doing it for hundreds of thousands of years, so our minds have evolved to figure out how to navigate these worlds and some things we know. We know that the illusions that people see across societies vary. So if you read a look at a textbook on cognitive psychology, you might see something like the molar allusion which has the arrows in or the arrows out well, and if you're in Chicago you'll you have to see. One line has to be twenty five percent longer than the other line before people perceive them in Chicago as the same length. If you study hunter-gatherers, they don't see the illusion so basic. Visual perception. Depends. On the world you grow up on. Self. Regulation is affected by religious devotion. People who engage in daily religious devotion have greater self regulation. It's cultural practice, same thing with the others. I could go into secret of our success gets into something.

all right, and the last thing i'll mention is that we're at the stage, and the evolution of the social sciences where we have to get rid of the the dualism, the you know, culture. On one hand, biology, on the other hand, when we grow up in these worlds it changes our brains. So you can take genetically identical twins. Raise them in two different societies. They end up with different brains.

So that's just that's just a fact.

Okay. And then my interest is actually, I think this has been going on for a really long time. So i'm interested in how this has shaped features of human psychology.

All right.

Okay. And i'll just make a comment on the culture and institutions question. Just because this seems to be an ongoing issue in economics from the perspective that I've tried to lay out here There's no Is it institutions, or is it culture? Because institutions are a product of cultural evolution?

So people learn from each other, and this gives rise to social norms. What are social norms?

So they are. Ah! You acquire both the behavior. Don't, eat pig, and the rules for judging other pig eaters or bad news. And so then you get a social norm that prevents some group from eating pig. It's it's enforced. It's self-reinforcing, and you can build game, theoretic models it'll remain stable that sort of thing, so that gives rise to norms collections of norms that govern a domain or institution.

So marriage societies have had marriage institutions, for as long as we can figure, and marriage is governed by where the where the couple lives after they get married. Who pays bride price or dowry? There's all these rules surrounding marriage. It's an institution so formal institutions. The only difference is there you can write stuff down, and then future generations can interpret it all right now. Kin based institutions, i'm going to argue are special as institutions go, because we have an evolved psychology that we share with other animals to preferentially be altruistic towards those who are genetically related to. So those who have a probability of sharing the same altruistic genes.

It's quite a bit of research on that. But kinship systems extend that so lots of societies will call cousins, brothers or sisters, and you're supposed to treat that person like us like a classicatory sibling. You're also not supposed to have sex with them, if you call them sister, and you're a male, or and vice versa mit ctl and um. We also have a pair Bonding instinct, and marriage builds on that so like gorillas, who also have a pair of bonding instinct. We form long-term emotional bonds for the purposes of child rearing and protection. And then marriage formalizes that reinforces it et cetera, one hundred and fifty, and then finally incest aversion. Like other animals, we have to avoid inbreeding with close relatives. So we have an in a diversion that we develop towards siblings. People will grow up in the same household with, but that can be extended and created an incest taboos, and apply to in-laws apply to cousins other other members of the group,

and even hunter-gatherers in the Kalahari would, if you asked him about sex with a cousin they'd be like. Well, that's like having sex with my sister, and they'll they'll actually make the link, and everybody knows what that sounds like. The sibling of what that feels like.

So Anyway, these structure human social networks, and they're highly variable across human societies. It's good to ask why. And that's one of the things I want to do.

And then, finally, one of the arguments and the weirdest people in the world is that the emergence of pre-modern States were really built on the logic of kin, based institutions so lower strata and upper strata. Think about kings and queens, and marrying cousins and lineages, and all that stuff, and of course, the lower strat. It worked as a productive unit. They'd re, you know, arranged marriage, that kind of thing, and it was really this thin layer of, and in personal institutions sandwiched between two versions of complex kinship that made pre modern states work mit ctl. And and it's hard to get to modern states. If you have all this complex kinship operating in the background. So part of this is an argument about where modern states can come from one hundred and fifty.

Okay, Now, all of this talk about kinship and clans and stuff may seem unusual to at least some of you. Ah, because you come from these weird societies, and just to give you a sense of how  unusual it is. These are a set of kinship traits that vary around the world and bilateral descent. So tracing descent through Mom and Dad. Most societies Haven't had that they've had something else. Patrilineal descent, matrilineal descent. So that's rare cousin marriage seventy five percent of societies have some form of cousin marriage. In some places it's preferred monogamous marriage.

Eighty five percent of human societies have allowed high status elite males to take additional lives. Nuclear families rarer yet ninety two percent of societies. Haven't had nuclear families. They're organized in some kind of extended family and near local residents. So that's when the bride and the groom lives separate from either the bride or the groom's family, and that's even more rare if we look at the world as presented in the ethnographic Atlas.

Most societies have none of these weird traits. So fifty, one, fifty point, one percent of societies have zero. If we look down at other societies that have five. They're either European descent societies that appear in the ethnographic Atlas, or they're places where usually Spanish missionaries have arrived early.

So I actually found there's this island of Sebu, which has weirdly five of these, all five of these traits. So I went and did research on it, and I went to Antonio Pig fed his journal of Magellan's Chronicles, and he records polygeny like crazy and cousin marriage, and all that stuff in Sabb. But then the Spanish Dominican missionaries got there, and by the time the anthropologist wrote stuff down, the Spanish missionaries had done their bit, kay, So families are a great place to start, because they're where children are born into. So they're the first institution kids encounter, and they're historically the oldest institution. So everything we know is that some societies only have kin based institutions.

All right. So where did they come from? A common assumption is that these come from wealth? People get rich, and then they start living in monogamous nuclear families. That's what everybody wants to do. Right?

Um. But there's good reason to believe in. Historians and anthropologists have long argued that it was actually the action of the Roman Catholic Church, one branch of Christianity that dissolved the complex kinship networks of Europe into monogamous nuclear families,

And one fun piece of evidence is that you know all of us speak English. We know the term for affine, so that's the anthropological term. But if you where does the in-law come in? Sister-in-law, or brother-in-law or father-in-law, it comes from in canon law so every time you say sister-in-law you're channeling the Catholic church's taboo on sex with your sister-in-law or sex with your brother-in-law, because that was supposed to remind you treat her like a sister you can't marry her.

Important, because even in the Bible there were forms of marriage, where, if your husband died, you'd marry his brother so like Leverett marriage so oral marriage very common across societies. Church does away with it.

You're also, maybe familiar with the common thing in marriage ceremonies. Oftentimes the priest or preacher will say something like if any one here can show just cause why this couple should not be lawfully joined together in holy matrimony, let them speak now or forever to hold their peace. That comes from the caroling gene. Empire's effort to root out incest meaning marriage with cousins, and you get everyone together, and you say, Ok, are these two related in any way? Does anybody know how they might be related? And that's essentially what that is?

Ah! So eventually the church begins in late antiquity bands first cousin marriage, but it eventually goes out to six cousins, and then it contracts a bit in twelve, fifteen. Ah! Down to third cousins, but still pretty broad incest taboos, Remember, most societies have cousin marriage. Seventy five percent of them.

Polygamy also is banned. Europeans had polygamy like crazy secondary wives all that kind of stuff before the church.

Um no arranged marriages so very common cross-culturally the church required bride to the the Christian marriages still have. The bride has to say I do. At one point Most societies don't ask the bride her opinion. Ah, but so the church forces that, and the priest is supposed to be checking. Right? Okay, you're good with this right?

And the church also discourages corporate ownership. So they wanted people to be able to give the church land, and if the uncles can get a hold of the land after their brother dies, the church can't get their hands on it, so they they try to confine ownership to the individual and prevent collateral inheritance.

So the a great book to read about this is Jack Goody's development of the church and family and marriage in Europe.

Oh, gosh! What happened to this slide? Um. Okay. So this is just the same thing I was showing you before, and i'm going to focus on this link and this link, all right. So the first thing that I may need to persuade you of is that there's a lot of psychological variation around the world, and if you didn't know about this, you'd be forgiven. Because if you take a course in social psychology, there's a social psychology text which presents it. As if this is how people think, when actually it to how weird people think uh. So just to give you a sense. This is a measure of individualism around the world. Ninety-six percent of psychology studies are with European descent populations, the Us. Primarily. So they're studying some of the most psychologically unusual populations around the world. Similar things with differences between trust in your out group versus trust in your in group.

This affects beliefs and preferences. So here i'm thinking of economists. But if you're a cognitive scientist, it also affects attention, memory, perception, reasoning, decision, styles, and and a challenge. I have yet to find a decision-making heuristic, prevented by the found by the behavioral economist that doesn't vary across societies. There's either no evidence or I can show you there's a variation.

And I'm going to focus on individualism in personal trust conformity and and patients which, at least to an intuitive first approximation, might affect economic outcomes.

Okay, Now, one thing I have a caveat, which is that people from societies tend to think traits that promote success in their society are good. Ah! And so they tend to negatively balance things. And some people think you know. Why are you saying bad things about these people calling them conformists?

You know it's thinking of a more conformist society. But in those societies being a conformist, is good, so um conformity is well-studied. So if you show Americans parents with their child behaving in a conformist way in a Nonconformist way. The American parents like the non-conformist They'll be like that Kid's smart, you know, we we like that kid. Whereas if you go to other societies and show a conformist and a non-conformist child you know same videos, they pick the other kid Mit.

Okay, Now, I want to give you a sense of why our psychology would vary. So i'm going to think about an intensive tin based society and a weak kinship society.

So in an intensive kinship society you get your relationships at birth, and a lot of life is about figuring out how to navigate those relationships live up to your responsibilities.

You can form to the roles and obligations of this society might be. Why, conformity is good? Because you're trying to. You know not shame anybody Now, in a weak kinship. Society, you don't have very many family connections. You have to find your ah mates and friends and partners and all that kind of thing by cultivating a set of attributes that make you interesting to other people. So maybe you want to be creative or trustworthy or honest mit seek. Others based on attributes and mutual interests, seek new relationships based on existing network connections. So in lots of places you're not worried about whether someone has a trustworthy disposition.

You want to have a lot of social connections to them, because if you do, you know, they'll behave in a business relationship, say, and and other kinds of relationships. It's the linkage between ah people. So trust is based on embedded embeddedness and trust, based on dispositions.

Ah, these these tend to be shame oriented. So you're trying to not violate social norms. If you do, other members of your family could experience shame so social standards here. Here. Guilt is often your personal standards, so I might feel guilty for not going to the gym, because i'm trying to stay in shape. But my neighbor doesn't care about that. And if they find out my brother's not going to experience shame. But i'm feeling guilt, something like that.

And here your identity is based on relationships and network. And here it's that set of cultivated traits on the scientist. I'm a kayaker, that sort of thing.

Okay. Now, empirically, the case we set out for ourselves in the science paper was we needed to connect the church to kinship. We need to be able to connect kinship to weird psychology, and if both of these hold we should also be able to do this.

So. Ah! We have the kinship, intensity, index, which I told you about. We also got a lot of data on cousin marriage. We can do that within Europe based on dispensation requests. And then we also have measures from this biologist in bittles, and then we have measures of the duration of the church's marriage and family program which we can calculate globally or within different European regions based on the diffusion of bishoprics.

I'll say more about that in a second. So this just gives you a sense of cousin marriage around the world. One in ten marriages even today, is between cousins, the pashtun in in Afghanistan, fifty, two percent cousin marriage. That's the Taliban as a pashtun organization.

So I want to avoid doing. I can show you I can show you seventeen different plots like this for seventeen different psychological variables cross nationally.

But let me summarize all that, and it summarizes nicely by this plot more centuries under the church for a population less cousin marriage. The same would be true if I put kinship intensity as measured from the ethnographic atlas, so that link holds cross nationally, more cousin marriage, less individualism and impersonal psychology. So people are less individualists more relationally oriented. And then, finally, we can go this way, and in all of our analysis we always do. The Eastern Church, which had a kind of a soft, less enthusiastic version of the marriage and family program that the Western Church imposed to dismantle the family structures in Western Europe. So you often see a weak but positive correlation with the Eastern Church, and then the strong result with the Western Church. So with the crossnet we see lots of variation cross nationally it roughly seems to pattern how we think it might pattern.

But we want to dig in and see if we can get closer to you know, build more confidence in that. There's really a relationship here.

So my collaborator, Jonathan Shilts, created a database of the diffusion of Catholic bishoprics through Europe. So we have a Gps location and a year, and so we can use that to assign a dosage to each place, and this is actually spiraling through time. So it just started. You'll see certain places turn gray.

That's because that part of the of Europe was under a political power unfriendly to the Bishop of Rome. So the Pope in Rome you'll see. Southern Spain deal is so Sicily. Well, Sicily's under Islamic powers.

Okay. So you get this variation in dosages. We have the Carolingian Empire here, which which may come up later, and we have also the the Iron Curtain, both of which we have to deal with in the analysis.

But just ah! To to measure psychology. We use questions from the European Social Survey. Um, I won't. Go into the detail, but they asked about conformity and obedience, individualism, independence, impersonal fairness, and in personal trust. So we get variation around through hundreds of thousands of Europeans. Ah, contemporary, and we see if we can explain the variation, and what we find is that regions. So we have four hundred and forty, two European regions that had more exposure to the Church mit ctl, and have greater impersonal fairness, greater impersonal trust, less conformity and obedience, and greater individualism independence. So we're only comparing Europeans and Europeans. Here we're just doing it within the same country. And so we're comparing different regions of the same country two.

We can hold individual demographics, so sex, age, h squared income and education are important ones. They don't seem to do much work at all.

Geography, climate, the influence of Roman roads, initial prosperity. We also put in medieval universities, monasteries, and the Carolingian Empire. One of one of the most persuasive analyses for me was when we threw out Western Europe, and we just do this analysis on Eastern Europe, and we find we can explain this variation in these aspects of psychology within Eastern Europe.

Okay, Um. We also managed to get some cousin marriage data. And so this is the percentage of cousin marriage on a log scale, and that's conformity. So more cousin marriage in Italy, Spain, France, and Turkey, we get greater conformity and obedience, less impersonal trust

and less individualism, independence, and less impersonal fairness. So interestingly, Turkey, which actually has a very different history right from places like France, they fall right where they should be on the plot. Once we know the rates of cousin marriage, so one of the differences could be this shift in kinship.

Um, i'm actually going to just really short-circuit this because i'm looking at the clock. But we did this trick, which is a fantastic trick from economics, where we look only at second-generation immigrants. So these are people who grew up their whole lives in Europe, but their parents come from somewhere else, and we can actually tag them to an ethnic group.

We tagged that individual who grew up entirely in Europe with a kinship intensity, or a cousin marriage rate from where their parents came from, and then we can predict aspects of their psychology and control for their income and all that sort of thing all right.

Okay, Now, one of the things I wanted to explain in the weirdest people in the world was that industrial revolution simple topic, because it shouldn't take long. Ah! And i'm interested in this idea of the collective brain which I develop in the secret of our success. And there the idea is pretty simple. It's that most innovations are recombinations of different ideas. So the things that should feed into that you want larger populations. You want more cognitively diverse populations, and you want more free flow amongst individuals. So we can get together and swap ideas.

So that's the basic idea of the collective brain, and I apply it to you, fluid social interactions among cognitively diverse individuals. And I look at the institutions, and I also look at the psychological relationships between innovation and and those psychological traits, but something like the journeyman phase. And an apprenticeship means You've apprenticed under a master, and you're probably he's probably not your father, which is unlike many places or another kin kinfolk, and then you have to go to somewhere far away. It's. Like a post-doc, go somewhere far away and hang out with a bunch of other people who apprentice under somebody. It seems like a perfect environment for creating recombinations of diverse ideas one hundred and fifty.

But in elsewhere. If you look at India, you read the literature on apprenticeship. There you look at China. Their clans wanted to keep secrets, or there were regional specializations. Nobody wanted to share information.

And then, finally, the psychological factors that'll create this recombination. Of course, the crucial here is is tolerance.

Okay. So to try to put this to the test. Uh, I started working with Slava Savinsky, who's in the crowd, and Jonathan Schultz, uh former postdoc in my lab, and we took the patent database from uh one thousand nine hundred and eighty to two thousand and fourteen, and that gives us a Let's see. This gives us a measure of patents across Europe, and the idea is, is, we think, that you know, the social networks which allow people to swap. Ideas are going to promote more patent and greater individual, is a nonconformity and impersonal trust. Those same measures that I just told you vary around Europe should lead to more patenting. So does all this psychology stuff I'm talking about on this survey, which you know just could be a bunch of survey answers, but as a cash out and more patents, and we also have the same measure. So again, our hands are tied right. We already tied our hands in the science paper.

So these are the new patent database that Slava put together. You can see It's these very small nuts, three regions in Europe, so over one thousand four hundred regions, and then we have our measures of ah trust, fairness, individualism, and conformity. And the basic question is, is, Can we explain the patents using those as a first step, and what we find is that we can take each of these pieces of psychology, and each one of them will explain patents in a regression holding the country constant and and other stuff. So a standard deviation increase in weirdness, or in in any of these four traits, will lead to between a point two, seven, and point four, three increase in patents. So that's a pretty good increase in patents and patent. Here is my measure of innovation. There's lots of interesting arguments about how good a measure that is. But it does seem to have some some value if we do a principal components on these four pieces of psychology and get a single dimension. We get over half a standard deviation increase in patenting across these different regions. So just a quick look at the standard economics table. So this is each of the four, and the weird psychology with the principal component um country fixed effects, so only comparing people in the same country all the standard battery of of geographic controls and things like that, so that suggests that innovation might be related to psychology. We can do the same thing with our nuclear families. They still vary across Europe, and and we have a measure of that. Or we have this measure of Facebook friends. So what percentage of Facebook friends are over one hundred miles away, And we use that to explain the patents. So, just to give you an example of the kind of result a one standard deviation increase in far away Facebook trends increases. Ah! By a quarter of a standard deviation. Patents per capita across these different regions. So this network thing seems to hold, and we think they're co-evolving with the psychology right? So so those are correlated. But can we go from the church. So this is our medieval church exposure. Bin scatter plot. So each of those dots is a combination of of dots and patents per capita. So it's a partial regression plot, more church exposure, more patents per capita.

Okay, and just the the long arm of history here. So patents per capita is the thing we're trying to explain. And medieval church exposure is Ah is we? Can. We can still pick up that long arm, and i'm making the case that this is due to its effect on psychology and families.

This holds even when we use small administrative regions. So these are subnational regions. So we're really only comparing people that leave which in some small part of Germany rather than all of Germany and all of France, those kinds of things.

Okay, um. I took this out, but somehow I must have not saved that version of the Powerpoint. Ah, so this I just find it amazing, and i'll just mention it here because it's the slide is here, but we have our centuries under the medieval church, and that predicts patents.

But then Jonathan Shilts had gone through the records. You know some historians had helped them a lot, and he found that at these different Bishop Bricks they took attendance when they had a big meeting, and we know all the issues. They talked about. The church keeps good written records at the meeting, and we know who attended. So we have an attendance list.

So Jonathan was able to put together a data set that has, whether the bishops in different parts of Europe actually attended the meetings where incest legislation was discussed, and that picks up some additional variation in patents. So the idea is, the Bishop goes to the meeting. He gets fired up about stamping out incest  mit Ctl, and people believed it was causing all kinds of problems, right? So people were marrying their cousins, and God was angry. And so he was sending plagues and ah, economic hardship and things like that. So it's like a public health campaign. So we had to get rid of the incest one.

Okay, Now this. Uh i'm always nervous when I present Iv regressions in front of economists.

So here here the idea is, we think that there's a case that can be made that medieval church. The Church is kind of expanding ideosyncratically wherever it sees a a chance to to kind of get a foothold, and wars are one in law, sometimes by a single battle due to luck. So maybe this is exogenous. But so we use medieval church exposure to predict aspects of psychology which it does nicely. I already do that from the science paper, and then we use the predicted values uh to predict patents per capita, and it comes out. It comes out very nicely.

Maybe there was the ah, maybe this fits the required restriction. Um, exclusion, restriction. Maybe it doesn't, but we did that, and we can show the same thing if we do it this way, where we're looking at the social network data, the Facebook friends or the um nuclear family households, so that seems to make the connection there and then. Finally, I'll just very briefly touch on this.

There's a bunch more analyses in this paper, but One of the things we did was that Carolingian Empire. The historians tell us that the the Carolingians So this is Charlemagne, eight hundred Ce. He. He teams up with the Church and the Popes, and they really try to impose the marriage and family program within the boundaries of the Carolingian Empire.

And if that story holds, we should be able to find that there is a drop off in patents when you cross the border of the Carolingian Empire. So if we can do it for the full sample, but we can also do it for different parts of the Carolingian Empire around Europe, and we get the same result in each piece of Europe.

Um. And again, you know, keeping country constant, at least for those first.

Okay, All right. So that is the basic picture. So there. I'm. Making the case that events that happened with how the Church transformed the family led to differences in psychology and social structure that have implications for innovation today

in the weirdest people in the world. I try to look at different places as well. So kinship intensity varies a lot within China, and even among high Han Chinese and researchers. I'm. Here I'm. Drawing mostly on Thomas Talhelm, but but others have argued that Patty Rice, agriculture, and also environmental risk based on monsoons has affects the presence of clans, and these lineages that spread after one thousand Ce.

So Paddy rice leads to greater kinship intensity, and Thomas has shown by collecting data all around China that that's associated with ah, greater analytic thinking, more individualistic self-concept and less in group loyalty. So it fits the same pattern of psychological variation. If you just look at Han Chinese within China, and it's based here in kinship variation, but not due to the church due to ecological factors that affect kinship, intensity since the book. Ah, Augustine Bergeron, an economist who who graduated from Harvard economics. He has looked at the way in which he's looked at the democratic Republic of Congo, and he has people living in the same city of Conanga,

and he traces them back to their natal villages, and then he asks how close those Natal villages are to historical Christian missions, and the closer the Natal villages are to the historical Christian missions, the lower the kinship, intensity of the individuals, and the higher they are on moral universalism and lower on in group loyalty. So to see the same pattern just analyzing populations within the Drc. Where here it's through Christian missions.

And then, finally, this recent paper by the folks at the University of British Columbia, Goshen colleagues.

What they do is they look at State law. So European populations are expanding across the Us. And some of them are isolated. Their cousin marriage crops back up because the Protestantism didn't embody the same taboos as the Church. Uh cousin. Marriage spreads a bit, States imposed laws that banned cousin marriage, and he's able to show that that reduces the amount of cousin marriage, and then that leads to a greater income and urbanization in the longer run. So that's the ghost paper.

Okay, so ah, final take-home messages is that i'm making the case that we can think about culture systematically. It's something We can measure shapes, economic and political outcomes.

What I actually presented is not a story of historical, of historical persistence, but is actually a story of historical change. So the Church gets these different peculiar views about marriage in the family, and they then use that to T, or that ends up, leaving them to transform the families of Europe, and that change, then leads to different cultural evolutionary trajectories and economic growth.

Um, Okay, Crucially, here is the idea that institutions and psychology co-evolve. So our minds have all that plasticity because we're a cultural species, and we're responding and and learning ways to better navigate the cultural worlds that we confront, and it affects lots of features of our our psychology.

And then, lastly, ah! You know the the place where we're coming from takes evolution very seriously, so you can't get kin based institutions correct. Unless you realize we have pair bonding, We have kin based altruism, and we have incest avoiders which gives incest taboos their power psychologically. And it also means that kinship institutions will always reassert themselves. So they're somehow more natural than anonymous and personal institutions where you have to be nice to strangers and things like that one.