Kin are a Group

A few days ago Eric Michael Johnson (formerly of this parish) put up a post about laboratory evidence for the breakdown of the selfish gene, which he started like this:

My previous post on a potential problem for the selfish gene theory in explaining cooperative behavior resulted in a fair amount of heated discussion. However, there are quite a few misconceptions regarding the controversy surrounding the selfish gene, group selection, multilevel selection, generalized reciprocity, etc. that need to be clarified.

He then went on to perpetrate some of these same misconceptions.


Eric claims that selfish gene theory needs expanding to include multi-level selection. He illustrates this with an experiment Bill Muir carried out many years ago. Bill is a chicken breeder1, and was worried about the welfare of battery hens. These hens are kept together in small groups, without having bountiful acres to run around in. Instead, they would squabble and fight, which would decrease egg production as well as making them unhappy chickens. Bill had the idea of selecting chickens that would be more sociable, and he did this by breeding from chickens which were in the most successful group. He did this and raised an über-race of sociable chickens who would produce lots of eggs whilst doing little more than sipping tea and nattering about how Edith in bay 73 has never been the same since she tried to remove her comb and escape to Antarctica.

How do we explain this? If we put some nice chickens in with nasty, selfish, chickens, the nice ones get bullied. So, individually they are not as fit. But, the group as a whole is fitter so it makes sense to think about what happened at the group level. Hence we can talk about group level selection.
This is a subject with a long and rancourous past, so a potted (and not entirely inaccurate) history is useful. in the bad old days there was old groups selection, where the chickens’ behaviour would be explained as acting “for the good of the group”. This was swept away in the late 60s when it was realised that this argument didn’t work: if that’s what was going on, a bully hen would be able to dominate. Another explanation, kin selection (i.e. helping relatives) was also developed. But in the 1970s group selection made a comeback, partly due to the work of David Sloan Wilson who formalised the idea and explored the conditions when it works. This caused a lot of controversy, debates etc. much, no doubt, to the bemusement of Bill Muir. There are several reasons for the rancour: it was caught up in the sociobiology debates, for example. These debates have largely died down, but oddly the mention of group selection is still perceived as an anathema. People will happily work on the evolution of social behaviour, studying systems where it is obvious that there is selection at the group level, but are utterly unable to let that phrase pass their lips. I find this rather comic.
What makes this really odd is that the scientific issues have been settled. We know group level selection can work, and through George Price we have a powerful tool to analyse it. Ironically this development is an application of selfish gene theory. The idea behind selfish gene theory is to think about evolution in terms of genes, rather than individuals. So, for basic kin selection we know that individuals who are more related are more likely to share genes, and hence an altruistic trait that increases their fitness by enough will spread. But you’ve all read The Selfish Gene, haven’t you?
Anyway, this same argument can be used for groups. If I help the members of my group, at a personal cost to myself, and if they are more likely to share my helping gene than a random member of the population, then that gene will become more frequent than if I was helping random individuals. We see precisely this in the chickens: a gene for not beating up your neighbours means that you are less likely to get food. But if several of you in a group have that gene, the group as a whole benefits because there is less fighting. As long as the increase in the average fitness of the group is larger than my loss of fitness from being nice, being nice wins out. There is obviously a balance between the individual and group levels, and Price worked out the tools to make sense of this2.
Eric’s suggestion that selfish gene theory breaks down is wrong: we can use precisely this tool to understand the experiment. It is not the only way to analyse the situation, though. David Sloan Wilson developed a “new” group selection, which is more formal than the old one. This is equivalent to a kin selection approach, so if there is a debate, it is over which approach is better. i.e. which one gets results.
Last year there was a to and fro about this. That well known beat combo West, Griffin and Gardner had written a review of models of social evolution, and (D.S.) Wilson responded with a call for pluralism: for his approach to be allowed space. The response to this was academic pwnage. This was particularly devastating:

Wilson’s first example of the insights provided by group selection is the effect of population viscosity (limited dispersal) on the evolution of cooperation or altruism (Wilson et al., 1992). This problem of population viscosity and cooperation was considered by Hamilton from an inclusive fitness perspective. Hamilton (1964, 1972) suggested that population viscosity (limited dispersal) could favour cooperation because it would tend to keep relatives together – in this case, altruism directed indiscriminately at all neighbours could be favoured, because those neighbours tend to be relatives. However, Hamilton (1971, 1975) later realized that things might not be that simple, as population viscosity would also keep relatives together to compete, which would select against cooperation. The question is, what the relative importance of these opposing forces is?

Wilson et al.’s key contribution was to show that, in a simple-case scenario, these two opposing forces seem to cancel out, and so population viscosity has negligible influence on the evolution of cooperation. However, group selection methodology could not provide an analytical account of this phenomenon (see also Wright, 1945). Consequently, Wilson et al. were forced to use a simulation approach, that had to rely on specific parameter values and was less useful for general interpretation. This problem was solved by Taylor with the use of kin selection methodology – in just a few lines of algebra, he was able to analytically show how and why the effect of increased competition between relatives exactly cancelled the effect of increased relatedness (Taylor, 1992). This provides a clear demonstration of how the kin selection approach is easier to use (it allowed an analytical solution), while also providing a more general solution (that did not assume specific parameter values), and could be easily applied to a range of biological examples (see West et al., 2002a).

In other words, we can do things your way, but it’s slow and nowhere near as good. Put simply, a selfish gene approach is well developed, and is more powerful: we can get nice analytic results that explain what’s going on.
I think it must be frustrating for people who actually work on this subject to see these arguments come out. Indeed, this is what Kern Reeve and Laurent Keller wrote ten years ago in their introduction to a book on levels of selection:

First, however, we wish to make yet one more attempt to bury the issue that usually usurps discussions of the levels of selection at the expense of the truly interesting issues raised by these two problems; that is, the question of what unit is the “true” fundamental unit of selection. … In our opinion, these questions have been satisfactorily answered repeatedly, only to reappear subsequently with naive ferocity in new biological subdisciplines (e.g., the group-selection controversy is currently generating copious amounts of smoke within the human sciences; see, e.g., Wilson and Sober 1994 and responses; Sober and Wilson 1998). The particularly frustrating aspect of these constantly renewed debates is that, even though they seemed to be sparked by rival theories about how evolution works, in fact, they often involve only rival metaphors for the very same evolutionary logic and are thus empirically empty.

Thus, we first pause to heap one more shovelful of dirt on the units-of-selection debates (a) and (b) above by very briefly reviewing what we believe to be their well-established, correct (if not universally known) resolutions.

If they decide to write a second edition, this may only need slight editing.

1 Well, animal geneticist. But chicken breeder sounds funnier.

2 Actually, he was re-deriving Bill Hamilton’s kin selection results, but saw that the ideas extended to groups.

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12 Responses to Kin are a Group

  1. Richard P. Grant says:

    I’ll take your word for it, Eric Henry Grrl Bob.

  2. Bob O'Hara says:

    Actually, I’m Bill.

  3. Richard P. Grant says:

    Nope. This is Bill.

  4. Bob O'Hara says:

    I’m another Bill. One that isn’t as attractive to women in Helsinki nightclubs.

  5. Eric Michael Johnson says:

    Nice review Bob. I linked to it on my post. However, I disagree that with you that “the scientific issues have been settled”. I think Wilson and Wilson’s paper in Quarterly Review of Biology has reopened this question for a number of biologists.

  6. Bob O'Hara says:

    I don’t see that review as saying anything new, though. It’s the same old arguments that Reeve and Keller were complaining about. If it hadn’t been written by a couple of Wilsons, it would have sunk into obscurity.

  7. Bora Zivkovic says:

    You say “If I help the members of my group, and if they are more likely to share my helping gene, then that gene will become more frequent than if I was helping random individuals.” Sloan and Wilson model shows that the clause “more likely to share my helping gene” is not necessary. Thus, inclusive fitness is only a subset of group selection.

  8. Bob O'Hara says:

    Sorry, Bora, I was unclear there: more likely than over the whole population (i.e. summed over all groups), and I also assumed a fitness cost of helping. I’ve revised the post, now. I assume the “Sloan and Wilson” model you’re referring to is from Sloan Wilson’s 1975 paper (yay, also open access!), and he shows that these are (now) the conditions.
    “[I]nclusive fitness is only a subset of group selection” doesn’t make any sense. Group selection is the process, inclusive fitness is a tool used to analyse that process.

  9. Alejandro Correa says:

    And the beast: _ ¿which is thinking?_

  10. Bob O'Hara says:

    Oh, he’s one of those that mistakes “The Selfish Gene” for “The Selfish Individual”. Embarrassingly for me, it works too.

  11. Heather Etchevers says:

    This is Bill
    A.k.a. The Beast [TM]
    He gets pecked by chickens all the time.

  12. erplus plus says:

    it looks like many here have missed what the terms of this kin-vs-group controversy are.
    EO Wilson & coterie’s change of mind was forced by 1999 work by James Hunt who studied multiple origins of sociality in a wasp phylogeny in which all the species had about the same “kin selection potential” and yet he found that sociality evolved only when there were very strong “ecological” incentives (Hunt, J. H. 1999. Trait mapping and salience in the evolution of eusocial vespid wasps. Evolution 53: 225-237). But since ~2005 Wilson, Hoelldobler, etc, have hijacked the controversy.
    Some people have indeed started realizing that crucial for the existence/persistence –and thus for the evolution– of animal societies is not (or not so much) “kin selection” but rather the fact that there are very rewarding ecological niches out there in which biomachines that adopt group-approaches to foraging and interference competition are much more effective trophically than are biomachines which adopt “solitary-consumer/fighter/reproducer” strategies.
    This means that the evolutionary-genetical success of the genetic programs encoding such group behaviors is fully subordinate to the existence of such ecological opportunities!
    In other words: people have begun realizing that, e.g., “altruism” is also a winning ecological strategy, rather than just an example of the promotion, or not, of altruism genes and the rejection of (or invasion by) cheater genes.
    The social-ant colony, e.g., is an ecological machine that out-competes at the foraging- and interference-competition level most other organisms in almost any terrestrial ecological setting, i.e., a social-ant colony in the field cannot be reduced natural-historically and evolutionary-historically to just an example of an ESS immune to “selfishness” mutations that may undermine the genetic encoding of its sociality.
    EO Wilson indeed has always made a big deal of the fact that ant species monopolize nearly 70% of the insect biomass on earth, but he did not realize the implications of this until the wasp guy rubbed it to him and his coterie while they were still happily repeating the empty syllogisms of kin-selection numerologists [who meanwhile have even almost managed to deny Darwin (sic!) the credit for explaining the existence of sterile ants, etc., when he mentioned in the Origin Species that an individual's sacrifice can benefit the reproduction of its relatives, i.e., kin selection].
    This 70% means that evolution by “natural selection of individuals” delivers niche-occupancy strategies that suffice to claim only ~30 of the trophic energy monopolized by the insect Bauplan (assuming termites and other social insects are insignificant biomass-wise).
    The situation among many mammals is the same. Wild-dog packs and hyenas, e.g., beat the hell out of tigers and lions, and biomass wise they dominate.
    It is time for gratuitous faux-a-prioristic misused-math arguments to be confronted with ultimate natural-historical facts.
    And it is also time that the too-many cheapo-applied-math peddlers posturing as evolutionary biologists learn that “natural selection” is not the same as “evolution by natural selection”, that differential fitness is always caused by differential ecological performance (and never by carrying say an A rather than a T in gene X), and that evolution by natural selection is just something that “may” happen to genes when there is differential ecological performance at some level of biological organization, which however does not “prove” that the differential ecological performance is at the level of molecular interactions of genes (or of proteins; genes may suffice but are not necessary for differential ecological performance, but additive genetic variation in ecological performance suffices for evolution caused by  differential ecological performance).
    In other words, Sober’s 1984 [1984 sic!] book “The Nature of Selection” should be required reading for every evolutionary biologist.  Sober showed first that the “kin selection” oxymoron is a muddled verbal construct to refer to that special case of group-level differential ecological performance in which “selected” groups happen to also be kin groups (which happens most of the time but not always… see mutualism, e.g.).
    PS. I found this very recent paper below that studied this ecological group-performance vs. “kin-selection” issue within a clade of sponge-living shrimp.
    ===============
    Kin structure, ecology and the evolution of social organization in shrimp: a comparative analysis
    Author(s): Duffy JE (Duffy, J. Emmett)1, Macdonald KS (Macdonald, Kenneth S.)2
    Source: PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES Volume: 277 Issue: 1681 Pages: 575-584 Published: FEB 22 2010
    Times Cited: 2 References: 62 Citation MapCitation Map
    Abstract: Eusocial societies present a Darwinian paradox, yet they have evolved independently in insects, mole-rats, and symbiotic shrimp. Historically, eusociality has been thought to arise as a response to ecological challenges, mediated by kin selection, but the role of kin selection has recently been questioned. Here we use phylogenetically independent contrasts to test the association of eusociality with ecological performance and genetic structure (via life history) among 20 species of sponge-dwelling shrimp (Synalpheus) in Belize. Consistent with hypotheses that cooperative groups enjoy an advantage in challenging habitats, we show that eusocial species are more abundant, occupy more sponges, and have broader host ranges than non-social sister species; and that these patterns are robust to correction for the generally smaller body sizes of eusocial species. In contrast, body size explains less or no variation after accounting for sociality. Despite strong ecological pressures on most sponge-dwellers, however, eusociality arose only in species with non-dispersing larvae, which form family groups subject to kin selection. Thus, superior ability to hold valuable resources may favour eusociality in shrimp but close genetic relatedness is nevertheless key to its origin, as in other eusocial animals.