The Secret of Our Success: How Culture Is Driving Human Evolution, Domesticating Our Species, and Making Us Smarter Kindle Edition

Simple theories of humans and society are nice because they can be easily applied without such huge experience on different cultures or history. Modelling people as rational actors maximizing their utility functions quite well predicts the behaviour of peoples in markets. Such models give good guidelines to develop an efficient society based on free markets on the other hand and good basis for constructing right kind of incentives to people. E.g. taxing CO2 emissions to get people decrease their CO2 emissions. In same way the evolutionary psychology of seeing people and other animals as maximizers of their genetic fitness - or inclusive fitness - give a quite good understanding of the behaviour of humans.

But the simple models do not always work that well. Anthropologists doing field work have especially seen the power of culture and the high decree of differences between human cultures. Anthropologists have seen the huge role of culture specific social norms maintained by a) punishment of norm violators on the one hand and b) the internalization of norms at early age on the second hand. Co-operation is not only about kinship and reciprocity as the evolutionary psychology claims. Or not even about Folk Theorem and Equilibrium Selection as claimed by the game theorist.

This book develops the role of culture in human evolution. The story of humans is more complex than that of the universal human nature of neoclassical economy or evolutionary psychology. Culture is not anything which is just layered on top of our biological nature. Culture has an impact on genes. Cooking and stone tools for processing and hunting the food has had a huge impact on the genetic evolution of the human physiology - it had already an impact on the physiology of Homo Erectus. Most of the people already know how in some human populations, lactase persistence has recently evolved genetically as an adaptation to the consumption of nonhuman milk and dairy products beyond infancy. Culture has an impact on genes. But according to Henrich this is more of a rule than an exception.

Henrich also talks about self-domestication. The culture dependent social norms and the universal human way of punishing norm violators has made us to internalize the norms of our local culture at early age.

As Henrich shows humans are social learners i.e. imitators. Imitation is something which allows our culture to really build on the older knowledge. Cultural mutations happen and some of them enhance the effectiveness of the tribe. The selection happens not only between individuals based on their phenotype but also between tribes / communities based on their institutions or culture. We get cumulative cultural evolution instead of just individual learning. The Darwinian competition between individuals is enhanced by a competition between the groups who have adopted same culture and same tools and institutions.

We are a different animal. But we are not only smart chimpanzees but we are really ultrasocial smart animals who have developed cultural and biological mechanisms to extend our communities to people who we do not even know personally. We have extended our brains to communal brains knowing and learning much more than we can learn as individuals. We have developed institutions which allow us to trust other people to certain extent.

This is the book of year 2015 on evolution. I hope especially the people who have read the meme theory of Richard Dawkins Selfish Gene and who have thought that is the end of the story - to read this book.

It is curious that we have so many books about how culture influences DNA-based evolution and so few books about the evolution of culture. Joe Henrich's book is firmly in the former category. His book is all about the origin of human nature.

There are problems with studying the distant past: evidence is difficult to obtain; experiments are challenging to perform; and predictions are difficult to test. It would make sense for students of cultural evolution to look to modern cultural dynamics, which are not afflicted by these problems.

In fact, Joe doesn't discuss about cultural evolution very much. He doesn't provide an introduction to the topic or attempt to explain how it works. Instead he assumes a theory of cultural evolution and goes on to use it to analyze the evolution of the DNA genes of our ancestors.

Perhaps all the study of the influence of culture on DNA is a bias arising out of academic funding sources. Or maybe the researchers involved all copied each other. What risks getting lost here is the idea of culture as a largely independent system evolving along broadly Darwinian lines that operates on a different timescale to the evolution of DNA genes and proceeds largely independently from it. Ancient history is all very well, but there's also the modern world, technology, the internet and the future to think about.

Anyway, it's not entirely fair to criticize a book because of its chosen subject area. In fact, the book is vastly better than most books on the topic of human genetic evolution because Joe is using a sensible theoretical framework which includes cultural evolution. If I had to describe the book in one word, I would use the term "solid".

Joe argues for the importance of our collective brains, and against the significance of our individual brains. This is well-trodden territory by now, but Joe's book provides an excellent overview of this topic.

Joe has spent some of his life visiting the cultures he studies, and his book has many anecdotes from them. At the start I feared that the book was too anecdote heavy. For a scientists describing evidence as 'anecdotal' is a popular way of saying it is practically worthless. Fortunately, Joe goes beyond anecdotes frequently enough for me.

I was hoping to find material about the cultural brain hypothesis - which Joe publicly supported in 2012. This is the idea that was pioneered by Susan Blackmore, that culture drove the expansion of the human brain. However this idea got very little coverage in the book.

I was also expecting to find some support for and advocacy of group selection. The topic is rarely mentioned in the book. Joe does start out by saying that he is going to go beyond the kin selection and reciprocity explanations for cooperation championed by Dawkins and Pinker. He then spends some time in the book attempting to establish that groups of our ancestors regularly wiped each other out - but this seems obvious and uncontroversial to me. I was expecting some kind of case to be made for group selection, but I missed it.

Overall, I didn't find much to disagree with in the book. There were a few issues. For example, at one point, Joe proposes that millionaire generosity is performed so that others will copy them, and they will benefit from living in a more cooperative society. I'm pretty sure that this is mostly wrong. Virtue signaling explains such generosity. Millionaire generosity is largely performed out of reputational concerns - as proposed by Robin Dunbar in a paper titled "Showing off in humans: male generosity as a mating signal".

Joe argues that cumulative cultural evolution made our species special. This seems to be a fairly common position, but it ignores the fairly substantial scientific evidence that chimpanzees also have cumulative cultural evolution. The difference between our culture and theirs is not so much that ours accumulates and theirs does not, but that their cultural accumulations run into a low complexity ceiling.

I also worry about Joe over using the concept of a norm. There's more to cultural evolution than norms, and I'm concerned that constantly thinking in terms of evolving norms misses out the evolution of all the non-norms.

Another suspect section was titled 'move over natural selection'. Joe writes: "since the rise of cumulative cultural evolution natural selection has lost its status as the only "dumb" process capable of creating complex adaptations". I was left wondering whether Joe though cultural adaptations formed without selection, or whether he thought that such selection was not "natural".

In the end, I was left wondering about the author's position on many other points as well. Joe seems to have only covered the areas where the science was fairly settled. I would have liked to see more speculation and exploration of controversial issues. I guess then the book wouldn't have been so solid.