Sunday, 2 December 2012

Tim Tyler: Pagel, Wired for Culture (review)


Hi. I'm Tim Tyler, and this is a review of this book:

Wired for Culture by Mark Pagel.

The book says it is about how and why humans have evolved so that they were able to rapidly build today's large-scale, complex societies. It discusses cooperation, deception, religion, altruism, kin selection, reciprocity, reputations and language. This is an interesting set of topics and the book offers a unique perspective on them.

The book is largely about origins - so a hefty chunk of it is about things that happened thousands or millions of years ago. It is written more as a popular science book than a science book. The book was definitely a good read, but alas, I often found myself irritated, frustrated or in disagreement with the author while reading it. I'll start with some of the negative points, and then get on to what I liked.

The book is saturated with human exceptionalism. We hear that only humans have proper culture and a proper language. Mark discusses cultures and languages in non-human animals, but is ultimately dismissive of them, since non-human cultures are insufficiently cumulative, and non-human languages are insufficiently symbolic. I tend to emphasize the opposite perspective. I think it is important to see the close links between human and non-human animal cultures and languages and use comparative ethology to illuminate these features of human social life.

Next: cultural evolution. Mark is aware of cultural evolution, and it plays an significant role in his narrative. At the very start of the book, he discusses the subject in terms of memes, gives Richard Dawkins credit for the idea and then lays out his understanding of the topic. Mark cites Dennet, discusses brain flukes, rabies, and the Cordyceps fungus. Wilson's idea of genes holding "culture on a leash" is discussed and Mark invokes the Terminator, and HAL (from 2001) to illustrate how Wilson might turn out to be completely wrong about that. He discusses memes that produce suicidal behaviour, compares such negative memes to viruses and then discusses the idea of a cognitive immune system with its own internal Darwinian mechanisms whose function is to reject bad memes. This part of the book is quite good.

However, cultural evolution is not really the topic of the book. Indeed, it receives only occasional attention in the rest of the book. Instead, the book is all about human evolution in terms of DNA genes. Mark emphasises that culture is generally good for our genes, and generally treats culture as a set of tools that genes have used to get what they want.

Many of those discussing the origins of human ultrasociality invoke gene-meme coevolution, with memes driving and genes being dragged around in their wake. Mark does invoke lactose tolerance as an example of this effect, but this kind of scenario doesn't really feature prominently in his narrative. Indeed, in most cases, where I would invoke benefits to memes, Mark instead talks about benefit to genes - sometimes mentioning the idea that culture is generally good for us, or we wouldn't have it. There's quite a large literature on how genes and memes coevolved to produce the human social mind, and Mark hardly cites any of it. There are a few jabs at "strong reciprocity" and "group selection", but that's about it. Mark obviously has a strong scientific background, and he does have some understanding of cultural evolution - but I was left with the impression that he hadn't finished thinking through its implications, and hadn't read much of the literature on the topic.

The story of human evolution is really the story of the rise of memes. That story is far more interesting than the tale of the bigger brain and the modified vocal chords. By concentrating so much on DNA genes, Mark misses out most of this story. Cultural evolution is actually very important to understanding how human DNA evolved, due to meme-gene coevolution. For example, once people start to consider cultural evolution properly their story about why humans have big brains typically starts to look very different from the "Machiavellian intelligence hypothesis" that Mark advocates in this book. For me, the emphasis on DNA genes was the single biggest problem with the book.

Mark discusses the idea of "cultural survival vehicles" - using terminology that Richard Dawkins once attempted to bury. The idea of what counts as a cultural "vehicle" broadly corresponds to the idea of what a cultural 'organism' is. Organisms have poorly delimited boundaries in the organic realm - what with ant colonies, slime molds, and symbiotic unions - such as the Portugese man'o'war. However, the situation in cultural evolution is even muddier, with transient coalitions between memes arising on many different scales. CDs, MP3s, PDFs are examples of things that many would treat as cultural organisms. However, Mark doesn't really discuss the whole issue of what counts as a cultural "vehicle". Instead he defines "cultural survival vehicles" to be the cultures associated with tribes of humans, and then uses this definition consistently throughout the book. My assessment is that Mark's approach to the topic of what counts as a "vehicle" in cultural evolution was narrow, dogmagtic and poorly thought through.

Next Mark's treatment of group selection. Mark devotes a few pages to criticism of group selection in the book. However, he doesn't seem to me to have tracked the recent literature on group selection very well. For many years group selection enthusiasts believed that they had a new theory that acted as a superset of kin selection. However after many attempts to say exactly what it was that group selection predicted which kin selection did not, the group selection enthusiasts mostly seem to have given up on this, and now largely recognise that modern group selection and kin selection theories make the same predictions - and so represent different ways of looking at the same process. Mark embraces kin selection, but is sceptical of group selection - a position that doesn't make sense if these are ideas that make the same set of predictions - as most modern group selection advocates now agree is true. I expect modern group selection advocates won't be too impressed by Mark's criticisms. They will just say that he failed to understand their position. As far as I can see, they will be correct.

On page 81, Mark attempts to explain patriotism and nationalism in terms of a "special" and "limited" form of nepotism by which a single gene for altruism recognises itself in other individuals and then helps them. Mark's explanation of this phenomenon appears to be unorthodox to me. He offers no references to supporting scientific literature. I don't think the explanation Mark offers for the existence of patriotism and nationalism is correct.

Mark also offers an explanation of how individual cells in slime mold populations can help each other despite being unrelated to one another. However Mark's explanation seems largely unnecessary to me - since cells in slime mold populations which exhibit multicellular stages are almost always close relatives - a fact which Mark fails to mention.

I thought that there quite a few of these dud explanations in the book. The lack of references to supporting material and uniform authoratative style made it hard to distinguish to good explanations from the bad ones. I wound up not entirely trusting a lot of what Mark was saying, and making mental notes to check up on his facts in cases where he was presenting material I was not familiar with. That is not a great relationship for a science writer to have with the reader.

Much of the book is about the reasons why humans cooperate. However, this material is distributed over many chapters and covered in a rather rambling way. The book really needs a summary of this material, saying which mechanisms are important.

Mark's most frequent answer to the puzzle of cooperation is that it pays. This is true of reciprocity and reputations, and it's true with the forms of byproduct mutualism which are frequently mentioned in the book. The coverage of cooperation in the book deals reasonably well with the theories of kin selection, reciprocity and reputations - though the cultural versions of these theories receive rather cursory treatment. However the book had little coverage of the important topic of cooperation due to manipulation. I remember one section on the subject - about how people used religion to manipulate each other. Memes manipulate humans into interacting with one another because contact between humans facilitates their own spread - but Mark doesn't discuss such possibilities.

Towards the end the book has some rather rambling digressions. Genomic impriniting may be fascinating, but it doesn't seem to have a lot to do with the main topic of the book. Mark also discusses his research on human hairlessness as an anti-parasite adaptation. An interesting topic no doubt - but again, not a whole lot to do with the main theme.

While it refers to the relevant science there are very few citations of actual papers. Instead the work of scientists is spun into a narrative. It's a narrative that is pretty well written. The lack of references in the body of the text probably helps a little with the flow, but at some expense to the science. There are references for each chapter at the end, but inconveniently, there are no footnotes or endnotes to explain how they relate to the chapter.

Enough about the dubious aspects of the book. There's also a fair amount of good material in it:

The book contains a pioneering section on cultural kin selection. Mark offers an explanation for altruism in humans that invokes the green beard effect - and makes it clear that he thinks that the explanation applies to both genes and memes. He uses terms such as "cultural relatedness" and "cultural nepotism". He also correctly explains that the green beard effect is just kin selection applied to individual genes or memes. This material is good. However, there are no references and no attempt to place this theory in its historical context. Nor is it a very comprehensive treatment of the subject. I would have preferred this section of the book to be longer. I'm rather sceptical that the green beard effect is the best way of describing cultural kin selection. We don't describe organic kin selection in terms of the net effect of a bunch of green beard genes - and I don't see any terribly good reason for describing cultural kin selection in those terms.

Mark offers a fairly withering critique of use of the ultimatum game by some researchers to illustrate how humans cooperate in anonymous one shot interactions where reputations and reciprocity can't possibly be involved - and so therefore the observed cooperation must be down to group selection. Mark offers what seems to me to be the obvious refutation - that subjects tend to play it safe in case they are not really anonymous in the laboratory environment - an explanation which had been previously given by Andrew Delton in 2011. As Mark says, the ultimatum game represents poor quality evidence for kin or group selection.

In summary, this book is rather patchy, with some good bits and some bad bits. The good bits are good enough to make the book worth reading, though. It's certainly nice to have a professor of evolutionary biology using memetics and cultural kin selection.


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