Samir Okasha wrote a rather flawed book on group selection some years ago. However, this article shows that he is doing a good job of keeping up with developments in the field - and it isn't so easy to find significant mistakes in this large recent article.
I think one problem is that it takes the work of Nowak and Wilson a bit too seriously.
In one place the authors argue againstequivalence, saying:
In one respect, the kin selection approach is arguably more general than the multilevel approach, because the latter requires that individuals be nested into nonoverlapping groups, as in figure 4; this is necessary for the decomposition technique in box 2 to apply (Hamilton 1975, Okasha 2006, Frank 2013). Groups of this sort exist in some taxa (e.g., the colonies of many social insect species). But in other cases, individuals engage in social interactions with their conspecifics, but there are no well-defined, discrete groups. The kin selection approach can handle such cases easily; indicative of this is that in deriving equation 4 above (box 1), we did not make use of the fact that the individuals were nested into nonoverlapping groups. Therfore, the claim that kin and multilevel selection are formally equivalent requires at least this qualification.
This doesn't seem like too much of a stumbling block to me. The modern "group selection" approaches depend critically on defining a "group" to include any collection of organisms - no matter how fleeting or ephemeral. You have to buy into this conception of a "group" for the approach to be worth considering in the first place.
The authors say:
The widespread preference for kin selection may be partly due to multilevel selection's association with the flawed good-of-the-group tradition of the 1950s and 1960s and the associated superorganism concept, of which many biologists remain suspicious. It is undeniable that the careless appeal to group-level advantage as a way of explaining a trait's evolution led to serious errors in the past, so biologists’ wariness of this mode of explanation is understandable.
That's about the size of it. However, this paints group selection's problems as being in the past. I think that this is inaccurate. A fairly cursory look at the evolutionary social sciences shows that misapplication of group selection is still widespread.
The essay closes with a plea for "causal aptness": use kin selection when you have relatives, use group selection when you have interacting groups. This proposal sounds reasonable - but I think it would do little to stem the existing misuse of group selection. The problem is that people see differential group reproduction, reach for group selection, and produce just-so stories about how group traits are the product of differential group extinction or reproduction. This is a systematically bad methodology that use of group selection directly encourages. Using "causal aptness" would probably boost usage of group selection. That seems as though it is likely to cause a range of negative outcomes associated with the misuse of group selection - and so I regard the proposal as suspect.
"Causal aptness" is one proposal. A big health warning relating to the misuses of group selection is another. I think that, if you adopt the first proposal, you should also adopt the second one.
Hi. I'm Tim Tyler, and this is a review of this book:
The Social Conquest of Earth by Edward O. Wilson
The book is about the rise of social organisms on the planet and how they have come to dominate their ecosystems. Wilson uses ants and humans as his main examples of the success of sociality.
It's aiming to be a popular book. There are, in fact, a few scientific references in the book, but if you're not careful, you won't find them until you get to the very end - where they are clustered together in a list.
The first 100 pages of the book is a history of the rise of humans. Alas, I'm one of those who often finds histories boring, so I had to push a bit through this section of the book. Then there's thirty pages on social insects. Then there's sixty pages on the theories of social evolution. This is really where Wilson comes unstuck.
Wilson launches into a misguided attack on kin selection theory. Obviously, Wilson has some understanding of kin selection. However, he doesn't have a sympathetic understanding of it, and instead seeks to destroy and discredit it. Alas, in order to do this, he has to set up a series of straw men and then vigorously attack them. This might be entertaining for some - but Wilson is a popular author, and here we run the risk of an eminent scientist confusing and misleading the next generation of students. About the best that can be said for Wilson's attack on kin selection is that it is embarrassing and half-baked. I noticed that, as if to illustrate that he doesn't really know what he is talking about, Wilson gives an incorrect definition of inclusive fitness, saying:
The inclusive fitness of the individual is its personal fitness, in other words the number of its personal offspring who grow up and have children of their own added to the effect its actions will have on the fitness of its collateral relatives, such as siblings, aunts, uncles, and cousins.
That definition is wrong. Those familiar with the topic will recognise that it's only two thirds of the correct definition. Wilson goes on to discuss the claimed equivalence of kin and group selection. He says:
Further there are mathematical difficulties with the definition of r, the degree of relatedness. These difficulties render incorrect the oft-repeated claim that group selection is the same as kin selection expressed through inclusive fitness.
After supposedly demolishing the decades of work by kin selection theorists, Wilson goes on to present his preferred alternative theory of social evolution - which is based on group selection and the idea of group-forming forces - where Wilson gives a "defensible nest" as his main example of the latter.
Unfortunately, Wilson's book is probably exhibit number one when it comes to showing how group selection leads to confusion about evolutionary theory. Wilson is evidently in a hopeless muddle about kin selection and group selection. It seems hard to avoid the conclusion that group selection lies at the root of the problem. While Wilson might have been trying to help the cause of group selection in his book, it seems more likely that it will be an embarrassment for group selection's proponents.
Group selection's main problem that it faces a well-armed opponent. Kin selection explains all the same things that group selection explains - and has been scientific orthodoxy for decades. Most modern group selection enthusiasts seem to have finally agreed that group selection makes no predictions not also made by kin selection. The main case for group selection these days seems to amount to the idea that it represents a stimulating alternative perspective. High-level selection can be a form of holism to counter kin selection's reductionism. Group selection models can be tractable in some cases where lower-level kin selection models are not. This is all reasonable: group selection does have a positive side. The problem with group selection is that historically its use has often led to junk science. People tend to invoke benefits to group willy-nilly - without doing the math, or even sanity-checking their explanations. To many scientists, group selection explanations thus often look like a poor substitute for actually understanding what is going on. Many explanations based on group selection, on closer examination, have turned out to be wrong or misleading. In the cases group selection is useful, kin selection is often more useful. SO, group selection has its merits - but needs a health warning.
Wilson claims that humans are a eusocial species - even though we mostly lack one of the primary traits associated with eusociality - namely reproductive division of labour. Wilson doesn't explain that his use of the term is unorthodox and controversial.
Wilson's examples of eusociality are all from animals. He lists beetles, aphids, thrips, shrimps, mole rats and humans. However there are other examples of social behaviour among microbes, plants and fungi. In particular multicellularity is a common form of eusociality. The examples of its evolution illuminate the topic of social evolution. However, Wilson makes no use of these examples.
Wilson attempts to apply the study of animal social evolution to humans - and this leads him to the kin selection (or group selection) axis. While important, this leads to a pretty myopic perspective on human social behaviour, which is heavily influenced by reciprocity, reputations, byproduct mutualism - and manipulation of humans by memes. You can't really coherently discuss human social evolution without casting your net wider than this.
Lastly, the book ends up with a review of cultural evolution in humans. In the 1980s Wilson was a pioneer in applying biology to human culturally-transmitted behaviour, writing two books on this topic. Wilson at least understands that culture evolves - and that memes coevolve with genes. However, his older books promoted a pre-memetics perspective, in which everything boiled down to DNA genes. Checking to see if Wilson had moved on 40 years later, I was surprised to find that little had changed. He cited his old work, and trotted out much the same theory that he advocated back in the 1980s. This idea has been totally superseded in the mean time by the application of Darwinian evolutionary theory directly to cultural variation - along the lines pioneered by Richard Dawkins in 1976. Wilson's discussion of this work is confined to one paragraph. He chastises the researchers involved for paying insufficient attention to the interactions between genes and memes - and then launches into a laundry list of such interactions.
This hopeless treatment of cultural evolution might not matter - but this is one of the few books addressing the topic that I regularly see in bookshops. This might be the first exposure to the topic for many. A teaching opportunity has been squandered, because Wilson is stuck back in the 1970s on the topic and has failed to grok most of the more recent literature.
In the book, Wilson expands on his old claim that genes keep memes on a leash by presenting an argument against the possibility of a memetic takeover. He says:
I am further inclined to discount the widespread belief that robotic intelligence will overtake and potentially replace human intelligence.
What are Wilson's reasons? He goes on to give them, saying:
To advance from robot to human would be a task of immense technological difficulty. But why should we even wish to try? Even after our machines far exceed our outer mental capacities, they will not have anything resembling human minds. In any case, we do not need such robots, and we will not want them. The biological human mind is our province.
Wilson's objection seems simple-minded to me. He gives me no reason to think that he knows much about machine intelligence or futurism. He's just a famous biologist speculating on something about which he knows little. The idea that people will lack motivation to build superhuman intelligent machines just seems daft to me. The motivation is obvious.
So: this is not a good book. It is quite readable, but it's full of outdated or wrong science. Readers should be warned that, while Wilson speaks authoritatively, he doesn't really know what he's talking about in many places.
Hi. I'm Tim Tyler, and this is a review of this book:
Darwinism and Human Affairs by Richard Alexander
The book was published in 1979. The contents represent what we would now call sociobiology. Unfortunately, this is the bad kind of sociobiology that tries to trace everything back to DNA genes.
The book offers a perspective similar to that of E.O. Wilson - who published similar works at around the same time.
I read it mainly in order to understand Richard's perspective on human culture from that era.
The book predates our modern understanding of cultural evolution and instead presents a view of culture based on DNA genes.
In a section titled: A comparison of organic and cultural evolution, Richard breaks cultural evolution down into inheritance, mutation, selection, drift and isolation. He then reviews existing literature relating to the modern perspective on cultural evolution citing the views of Dawkins, Durham, Cloak, Cavalii-Sforza, Feldman, Richerson and Boyd on the topic. This might all sound good. However, the section then goes on to dismiss this material, saying:
regularity of learning situations or environmental consistency is the link between genetic instructions and cultural instructions which makes the latter not a replicator at all, but in historical terms a vehicle of the genetic replicators.
Having thus dismissed the Darwinian view of culture which does so much useful work in modern times, Richard offers in its place the idea that cultural information is a persistent part of the environment that is influenced and manipulated by genes. This is true - as far as it goes. However, these days, we know that you can get a lot of mileage out of the idea that cultural variation evolves in a very similar way to the way genetic variation evolves - complete with selection, adapatation, drift, recombination, kin selection, gradualism and heritage constraint. Richard's model is not exactly wrong, it just isn't as helpful as it could be. Because culture evolves, evolutionary theory has a rich array of tools and models which can be directly applied to cultural variation without much modification. If you fail to recognise that, you don't get to use these tools and models.
It is rather frustrating for the reader to see the author toy with the correct theory - and then abandon it. On a more positive note, it was probably good to have the position that everything boils down to genes clearly articulated - to give critics something to argue against.
Most of the rest of the book is concerned with explaining various types of human behavior in terms of DNA genes. Richard looks at nepotism, incest avoidance, xenophobia and various other aspects of human affair with a biological basis. He engages with anthropologists critical of biological approaches. While he makes most of them look stupid, some of their objections make some sense retrospectively. One thing they were critical of was the over-application of kin selection theory. Looking at the kin selection being advocated back then, only kinship between DNA genes was used - and all other kin-like relationships were classified as fictive kinships, with the organisms involved being manipulated and fooled into thinking their colleagues are their kin. This now looks like a terribly impoverished kind of kin selection, in the light of cultural kin selection. There's memetic kinship, as well as genetic kinship. The anthropologists didn't have the concept of cultural kin selection back then either, but at least they recognized that there was much more to kinship than relatedness between DNA genes.
Richard bashes group selection here and there in the book, but his story of how humans evolved revolves heavily around conflict between groups. Because of this, modern group selection enthusiasts may find him an ally as much as an adversary. Here's a sound bite from the book on the non-equivalence of kin and group selection:
Despite the recent prominence accorded to the view that the maximization of inclusive fitness by helping the aggregate of one's relatives - or what Maynard Smith called "kin selection" is a kind of group selection, this is a misleading, if not erroneous view. Group selection thwarts the reproductive interests of individuals when these interests differ from those of the group. Kin selection is a way in which individuals further their genetic interests via other individuals who carry some of their genes.
While this might have sounded plausible at the time, it now looks wrong. Group selection has turned out to be a way in which heritable information perpetuates itself via promoting copies of itself in other group members.
The book finishes up with a look at justice and ethics. Richard says:
Arguments given above, and the cited references make it clear why I believe that evolution has more to say about why people do what they do than any other theory. In contrast, my answer to the question "What does evolution have to say about normative ethics, or defining what people ought to be doing?" is "Nothing whatsoever."
I think this is a cop-out. Evolutionary theory surely has more to say about this subject than any other branch of science. If intelligent people aren't supposed to use science to guide their ethics, then it isn't clear where they are supposed to be getting their ethical principles from. Richard says that he thinks that pain and pleasure are the basis of most normative ethics - but even if one accepts that, classifying these as "non-evolutionary" ignores the idea that the brain evolved, and the idea that the brain evolves over an individual's lifetime, using copying, variation, and selection in order to to seek its rewards. I don't think you can get away from evolutionary ethics this easily.
This is a nice book to read, but pretty out-of-date these days. However it is interesting to see part of the background that modern theories of culture and human evolution were developed against.
Hi. I'm Tim Tyler, and this is a review of this book:
Plan and Purpose in Nature: The Limits of Darwinian Evolution by George C Williams.
George Williams is an expert in Darwinian evolution, and this book is an attempt to condense his knowledge down into a format which is easily digested by those new to the field. It is very readable and entertaining book.
It covers basic issues in evolutionary biology, particularly adaptationism, the unit of selection, sexual reproduction, senescence and medicine.
Williams embraces the term "The adaptationist program" - saying he almost selected it as the title of his book. This phrase originated with Gould and Lewontin - and was intended as a term of derision. No doubt Williams is making a point by using the term, but I would have preferred that adaptation enthusiasts left it alone - making it harder for critics to point at instances of the alleged phenomenon.
The book was published in 1996 - and I thought it was interesting to see what had changed since then. Williams offered an explanation for sexual reproduction that invokes generating diversity to help adapt to novel environments. For example plants like strawberries reproduce using runners and vegetative reproduction locally, but produce sexual seeds for transmission of offspring to a diverse range of remote environments. That is not a completely unreasonable explanation, but the modern way of putting it invokes parasites. If it wasn't for the need to evade parasites, the environment would often not change fast enough to favour sexual recombination. Williams does mention parasites, but they aren't the main feature. Another area where I noticed there were some oddities were in the chapter on senescence. The disposable soma theory and the antagonistic pleiotropy theory of aging are given without being named - and Williams emphasizes how senescence of living bodies is nothing like senescence of machinery - saying:
In thinking of senescence, the analogy to the wear and tear, or corrosion, or other process that ultimately causes an artificial device to fail is utterly misleading.
I think that the relationship here is close enough to not deserve being described as "utterly misleading". Indeed these days we have new modern theories of senescence - like "reliability theory" - that apply to both machinery and bodies, that highlight the relationship between senescence in both kinds of system.
The section about group selection has stood the test of time reasonably well. Williams says that most animal groups are not functionally organized, and that most groups are "just mobs of self-seeking individuals". That's true - though these days people might take more care to mention the possibility of cooperation with kin - i.e. genetic selfishness, not individual selfishness.
The section about medicine is welcome as well. However, while Darwinian medicine sounds nice, we seem firmly embedded in the era of "drug company" medicine, with little sign of an end in sight.
At the end of the book there's a section on philosophical implications. Williams describes the product of natural selection as immoral. He says "although the biological creation process is evil it is also abysmally stupid". His example of the horrors of natural selection is infanticide by males, which he argues is natural and adaptive - though obviously infanticide by males is certainly not adaptive in many modern societies today - since it is likely to result in extended incarceration. Williams endorses Dawkins' proposed rebellion against the selfish replicators and responds to naturalistic moralities with condemnation. This is a common position these days, but human morality sits firmly in the domain of evolutionary theory, and if your theory of evolution doesn't explain it, you need to rethink it. I figure that evolutionary theory offers reasonable explanations of morality that we don't need to apologize for.
Anyway, this is still a fine book - though perhaps some learned readers might find it too simplistic.
Hi. I'm Tim Tyler, and this is a review of this book:
Evolution and the Levels of Selection by Samir Okasha
I'd previously read Samir's Very Short Introduction to the Philosophy of Science. I thought that was good - and so I had some idea of what this book would be like.
The book contains an interesting and entertaining romp through the territory of group selection. It's what I call a "firehose presentation". In other words, it's a long stream of technical material that doesn't let up. This is a good match for my own preferences in a science book. Samir goes through practically every controversy in the field, and provides insightful opinions and commentary.
The book contains discussions of the Price equation and its significance, causality, emergence, evolutionary transitions, the gene's eye view, species selection, the group selection controversy and kin selection.
I thought the book was interesting and good. However, there were also quite a few parts of it which I disagreed with - or did not like. This is a reflection of the controversial nature of the subject matter.
The book dates from 2006. Throughout most of the history of the field of group selection, many of its advocates considered it to be a super-set of kin selection - often saying things like: relatedness is only one of many ways in which altruists can form groups which are then selected. However in recent years, the quest to find things that group selection explained - and that kin selection did not - seems to have petered out, with many of the most vocal group selection advocates now proclaiming its equivalence to kin selection. Samir's book predates many of these developments - and I suspect anyone writing a book on the subject today would treat the topic rather differently.
The book discusses kin selection only rather briefly. There's a discussion about it in the chapter relating to the group selection controversy, and another one in the chapter about evolutionary transitions. Samir recognises the possibility that kin and group selection might be equivalent, and cites several sources who claim that it is, sometimes approvingly. However, most of this book makes no mention of kin selection.
These days, I think few would approach group selection this way. Kin selection has a rich and successful history, while group selection has spent most of its existence mired in confusion and controversy. Kin selection has been much better studied. So: an obvious approach to many of the topics in this book would be to just use kin selection. However, it is hard to imagine this whole book being written in the language of kin selection. A good number of the issues just seem less important from that perspective. For example, in group selection there's the issue of what counts as a group. This broadly maps onto the issue of what counts as an individual in kin selection - yet this issue seems less controversial. Group selection faces of issue of how to model parly-overlapping groups - since most group selection models feature disjoint groups. Yet the corresponding issue of partly-overlapping families in kin selection seems less contentious. It's hard to escape the impression that the need for this book is partly because group selection is so awkward, difficult to understand and poorly-studied. Since kin selection is much better studied and much more widely used, it seems as though there would be less need for a philosopher to clear up misunderstandings in the field.
Samir offers several digs at the views of Richard Dawkins in the book. He criticises the idea that evolution is based on replicators, offering Hull's comment about them "passing on their structure intact" to claim that the term "replicator" implies high fidelity copying. I think that practically everyone on both sides of this debate agrees that high fidelity copying is not necessary - and it's high fidelity information transfer that matters for cumulative adaptive evolution. No modern users of the term "replicator" in biology use the term in that way - and many of them have objected to this persistent misunderstanding. Of course it's partly Richard Dawkins' fault for assigning an ordinary english word a counter-intuitive technical meaning.
Saimr also criticises the gene's eye view on two grounds. First, he says that it ignores behavioural and environmental inheritance. That isn't true if you adopt an information-theoretic definition of the term "gene" following Williams - since then memes are a type of gene, and the gene's eye view remains valid. Saimr also says that epistasis and "modifier genes" act against the gene's eye view. This is strictly true, but some linearity in the expression of genes is really all that is required to make the gene's eye view useful. Since a linear component in the expression of genes is ubiquitous, this issue seems like a storm in a teacup to me.
Like any complex technical book, there are some mistakes. The most embarrassing one I spotted was where Samir offered an incorrect definition of inclusive fitness - including the "augmenting" but not the "stripping" component - on page 145. Samir's explanations are usually clear - but sometimes the light fades. One such problem comes with the concepts of "MLS1" and "MLS2". Samir introduces these concepts by saying that they represent different focuses of interest on page 56. However on page 59 we hear that "MLS1 and MLS2 are distinct processes" and "whether either occurs in a particular case is a matter of objective fact". At best, this sort of material is very confusing.
Overall, this is a fine book - but I was left wondering if Samir had directed his energies in an appropriate fashion. The book will probably contribute to the modern group selection revival. However that revival seems likely to be accompanied by the usual muddle and confusion that follows group selection around like a black cloud. The problems with group selection at this stage are more sociological than anything else. Yes, groups exhibit reproduction and differential reproductive success, and that affects the course of evolution, but the problem is that practically whenever group selection gets used it results in junk science, or at best, science that is inferior to that which would have been produced by using kin selection. Looking at the mess that group selection has caused in the evolutionary human sciences illustrates this point. Does the world really need more group selection? After reading Samir's book, I was still sceptical. Samir doesn't address sociological questions concerning whether the muddle associated with group selection means that it does more harm than good. Instead, he just wants to clear up the muddle. But in that case: why not use kin selection? It seems much better studied, much less confusing, and has produced much less junk science.
What I think group selection needs most is clearly-articulated reasons to use it in place of kin selection. At the moment, the "why not use kin selection?" question is challenging to answer. Maybe there are reasons - but this book doesn't really provide an answer. It doesn't even ask the question.
Here's an interesting new paper: Kin Selection and Its Critics - Jonathan Birch and Samir Okasha.