A question about group selection

You need to add in to your equation:
–what predators are there? (Peacocks also use their tails to make themselves look big and scary)
–how hard food is to find, in an environment where food is abundant females don’t need hunters (see rising divorce rates in prosperous societies)
–it doesn’t actually matter who outbreeds whom if they aren’t competing for the same resources.

I am guessing…By making the two groups different species in your example, you eliminate the possibility of gene exchange between the groups, which would greatly reduce the effectiveness group selection.

I am not a biologist, but I would say that the selection you are describing is not happening at the ‘group’ level: each individual peacock has lower inclusive fitness than any individual penguin — no group level phenotypic features (eg cooperation) come into it. The fact that there are two distinct groups involved, rather than a frequency of an allele across a single population is a red herring.

John: Yes, but nowadays that’s how it’s understood. I’m not making a historical point, just stating how things are done in evolutionary biology now, as far as I can tell. In any case, the point remains: NS (at the gene, or, as a good approximation, the individual level) can explain adaptations, the mechanism you describe can’t. (Also, to clarify things, the mechanism you refer to isn’t group selection, it’s species selection, or clade selection. Group selection, in theory at least, could explain adaptations.)

Heather: DS Wilson has an undoubtedly interesting take on things, but it’s good to keep in mind that his views are still very much in a minority in biology.

I’m many years away from this topic but think you are confused by terminology. Group selection refers to intra-specific selection not competition between different species. The question is how altruistic behaviors can persist in populations and not be extinguished by selfish actors. That is, how can individuals act to lower their own reproductive fitness but still pass along sufficient genes for altruism to persist.

Why do you find the conflation of group selection with altruism a problem? That is how biologists view the issue. That is pretty much the entire issue for group selection.

Your example doesn’t involve group selection. It’s a question of inter-specific competition for resources. There is a vast literature on that topic which is totally distinct from group selection. When I left academic biology in the mid 80s, the inadequacy of existing models of competition was just beginning to be understood. One huge problem is that the environment and resources are not constants in any dimension.

If you re-stated your problem to involve individual differences within a single species, type one forages this way while type two forages some other way, it still would not involve group selection. It would then be a straightforward issue of natural selection for optimal foraging (optimal foraging theory is another vast area of research).

Each individual is a member of a group. If the members of one group individually survive and reproduce at a higher rate than members of another group competing for the same resources, that group will grow and the other diminish. This is plain old natural selection, operating at the individual level and manifesting itself in the aggregate.

I apologize if I’ve mistaken the question. My understanding is that the idea of group selection arose to explain some instances of social behavior which appear to contravene the individualistic logic of selection.

the selection you are describing is not happening at the ‘group’ level: each individual peacock has lower inclusive fitness than any individual penguin — no group level phenotypic features (eg cooperation) come into it.

Yes, this is correct. (And it’s an unnecessarily complex scenario too because you’re bringing in sexual selection pressures). For this to be a case of group selection, you’d have to somehow come up with a scenario where the behavioural difference was disadvantageous at the individual level, but advantageous at the group level, and that led one group to survive over the other. Like, say, non-reciprocal altruistic behaviour between unrelated individuals.

Just to clarify: reproduction is generally distinguished from social behavior. Birds are difficult to characterize. Their sexual activity ranges from opportunistic rape to lifelong monogamy, and the amount of care they provide for their young and its division between the sexes is similarly diverse, but the egg, hatchling and fledgling are the responsibility of at most two birds of the same species, not the flock, and the survival of their offspring depends almost entirely on their own competence.

Have you looked up the debates that happened (and are happening) around the EO Wilson, Nowak, and Tarnita paper in Nature on eusociality in 2010 (http://www.nature.com/nature/journal/v466/n7310/full/nature09205.html), the various responses (http://www.nature.com/nature/journal/v471/n7339/full/nature09831.html) and the attempts at a synthesis (http://www.bu.edu/writingprogram/journal/past-issues/issue-6/hammond/)? I think that’s a useful debate for getting a sense of the issues

the fact that this isn’t group selection has been pointed out already

it should be added that biparental care is not always the most fitness-improving – one could, e.g., instead look for resistance to parasites, where conspicuous display will be more helpful. The conditions which favour the “peafowl strategy” are not quite the same as those which favour the “penguin strategy”, so it’s questionable under what conditions these could coincide

on the nitpicking theme, some peafowl species are serially monogamous a la penguins

First, not an expert.

Couple of points: genes were originally seen as the primal unit, and this view remains strong (eg with Dawkins). But it’s now clear that genes are more like words in a language than atoms – what they do depends on multiple contexts (so the same gene can do different things, different genes the same thing, genes in cooperation do things differently than when alone and so on. And then there’s the burgeoning field of epigenetics – feedback between genes and environment – which mean that the same genome can do different things depending on environmental cues. So where is the continuous information stored? In the gene, the genome, or the genome and the environment? If the latter, then the environment includes the group to whatever degree that confers advantage.

Given this, and the common requirement for some minimum level of population greater than two necessary to sustain a species’ existence (and therefore the existence of the individual members of the species), there are clearly some effects at higher levels than the individual.

If you ask “what is the minimum size of a human population” the answer seems to be around 1000 (the smallest size a language can sustain itself), which in itself points to strong selection for large group size. Through what mechanisms this is maintained remains to be fully understood.

27: I think you’re getting yourself on a bit of a red herring with this sexual selection thing. Just posit two species of deer, Leapers and Creepers. Leaper deer have a genetic trait that means they spend one hour a day pointlessly jumping up and down. Creepers don’t. The two species are otherwise identical and coterminous in habitat.
Now, do Creepers gradually outcompete Leapers and drive them to extinction? Of course they do. Leapers are wasting time and energy; Creepers aren’t.
But that is definitely not an example of group selection. It’s an example of interspecific competition that is perfectly explicable in selfish-replicator terms. Leaping (or Creeping) is a “group-level feature” in the sense that all members of the group have it, but that doesn’t mean that it is a product of group selection any more than legs are a product of group selection.

I read a bunch about this after the EO Wilson paper that PGD linked to, and I came to a similar conclusion as Plutonium Kun: that the extent of condemnation is driven by academic politics more than anything straightforwardly scientific. It may not even map to real-world politics — academic politics can be intense for entirely internal reasons.

John @27 Suppose we add in a third population in which competition for mates takes the form of combat between males. Isn’t that a group level phenotypic feature?

Is that disadvantageous at an individual level? (i.e., is that in itself an example of group selection?) Probably not. Where there are losers, there are winners.

Is that group likely to lose to the “penguins” (as an example of penguins exhibiting group selection?) First – why would it? The conditions under which such intraspecific competition is favoured are when biparental care is irrelevant (perhaps because food is abundant). Male contributions in terms of sustained parental effort is irrelevant; male contributions in terms of disease resistance or such traits is far more appealing (again, as an individual rather than group trait). Under such conditions, the penguins are going to get their heads flushed in the toilet. Conversely, under the conditions more typical of the Antarctic circle, individual males who fail to invest in the care of their young will have poor fitness. The incidence of intraspecific competition is not an arbitrary event.

Second, suppose we do have Antarctic conditions, so that the “penguins” do have greater fitness. Why is that a group trait? Each individual penguin will still improved fitness compared to non-penguins.

First, I’m not an expert on group selection, but it’s something I’ve thought about with some care and to the limits of my capacity. As a result I’m basically agnostic – my capacity doesn’t allow me to go deep enough into the technical literature – but I do think there’s conceptual confusion sloshing around in these debates.

Count me among those who think the example you give is just plain-old interspecies competition, which is not what the group selection debate is about. In my underestanding, Doctor Science (#29) and BenK (#31) are pointing out the central issue.

I’m copying out a passage from an essay review of a book by DS Wilson on religion that I did some years ago (Rock Art in Darwin’s Cathedral). I hope it helps.

* * * *

What we observe, in animals as well as humans, is that individuals often do things that benefit the group but that cost them individually. As an example Wilson considers a hypothetical group of birds where individuals will emit calls warning the group of predators but also attracting the predators attention to them as individuals. These individuals are likely to attract the attention of these predators and so are more likely to be killed than others in the group and less likely to reproduce. Conversely, individuals who never emit warning calls nonetheless benefit from the calls of those who emit warnings and are thus more likely to reproduce. How can the genes favoring warning behavior reliably survive from one generation to another if signal-prone individuals are less likely to reproduce than “free-loading” individuals?

Darwin’s solution to this problem was to imagine that we have many groups and that those groups are in competition with one another. Groups containing altruistic individuals are more likely to survive than groups without them. Thus, we now seem to have a way of explaining how altruism can be inherited from one generation to another.

This solution, known as group selectionism, requires that the group be a real entity, rather than just some arbitrary collection of individuals. And that is where the problem is, figuring out the conditions in which this is possible. The problem was readily solved in the special cases of kin selection and reciprocal altruism, but a general case has been more elusive.

The problem is that groups must be relatively isolated breeding entities, for that is the only way to keep genetic variance between groups large enough for selective forces to work on whole groups rather than directly on individuals (Boyd and Richerson 1985; Leigh 1999).

Not an expert (in anything).

From a biological point of view, I think whatever stupidities Dawkins is uttering nowadays his contribution on gene selection stands. The notion ‘gene’ is problematic in itself but it is clear enough to exclude group selection (as Darwin already did).

I would however be surprised if JQ was writing on evolutionary models in biology. I see no reason why group selection could not be made to work in a game theory setting. Imagine a game between the group of humans and the group of whales. Clearly the strengths of some individual members in these groups are not very relevant to the outcome. Actually, there’s only one thing which makes the difference: humans act consciously as a group, the whales have little to do with it (at a biological evolutionary scale they might adapt by being either less attractive or more costly to track down but the speed of their game has nothing on the speed of human knowledge development). A more interesting game would happen if (say: Greenpeace vs. whale-killing industry) two groups of humans would compete. Then in the end one group would conceivably win (in the end: the argument) because they adopted the more successful social strategy.

Even in this case (at least let’s hope so) there’s a purely non-group element: which group has the best argument. The flat earth society might not be extinct fully just yet (important group dynamics hold pockets of it together) but I don’t see a social strategy in which they will thrive again.

The association of group selection with political issues goes back well before Gould and Dawkins, as the mention of Kropotkin illustrates–as will any anthology of Darwinian-influenced thought. Another example is Hofstadter’s book on Social Darwinism, from the sixties or seventies.

(Not a biologist)

Good question, this was interesting to think about. Here are some stylized facts for why group selection is difficult:

1. Populations of organisms, with genes of different frequencies, get selected* by their environment so that their phenotypes roughly ‘track’ the environment (climb the local hills in design space).
*Technically they all make copies and the least-successful copies are destroyed in the process of survival and reproduction, leading to a change in population frequencies over time.

2. Each organism (genetic pattern) is ‘trying’ to make the most copies it can. It competes for various resources in the environment, including food (against members of its own species, and rival species) and its own body (against predators).
Those patterns that make less copies gradually disappear from the population over time.

3. There are usually gains from cooperation— if two or more organisms work together and coordinate, they can get bigger payoffs than either of them could alone. However, there are almost always bigger payouts from defection-exploitation, and so cooperation needs some way to ‘pay its way’ or change the payoff matrix in order to make the larger payoffs reliable. Cooperation can arise from:
-Shared genetic patterns being copied across the pool of neighboring organisms (kin selection)
-Stable cooperation from iterated games (reciprocal altruism)
-Simple individual benefits from group coordination (mutualism)
-Incentive-alignment (costly punishment)

4. “Group selection” is about individual organisms that make population-level cooperative sacrifices, but *their genetic pattern is not paid back in fitness by one of the compensating mechanisms in #3*. Their pattern decays from the population, but the population expands to outcompete neighboring populations at a speed great enough that the individual altruist decay is dampened.
Classic examples would be a prey sacrificing itself so that the non-kin group can survive; or members of an overpopulated species sacrificing themselves so that the non-kin group doesn’t starve.
These patterns are not group-level stable because patterns that did not self-sacrifice would survive and copy in the long term. So to be stable, the groups that contain that have to beat other groups to a compensating degree.
Groups split into new groups much slower than organisms split into new organisms, so it’s hard to get the numbers to work out.

5. Cooperation and altruism are the focus of group selection debates because ‘increasing the total social fitness of a group, at the expense of the pattern’s individual fitness’, is the only puzzle that group selection could hypothetically solve, as far as I can see. What would be another example?

6. It may be clarifying to distinguish three different things:
A. Microfoundations altruism— kin selection, reciprocal altruism, mutualism, altruism-with-punishment-for-defection. These all make sense and are sustainable in a fitness economy— they pay their way in the fitness of individual patterns.
B. Group selection altruism— cooperative behavior that costs the individual more than it benefits (including in nearby kin patterns), but has such high returns for the group that groups with these individuals destroy and replace neighboring groups, ~even though the hypercooperative individuals are constantly decaying out of the population at the margin~.
C. Competition between different species that do not interbreed. This is just a separate topic, since there are no “genetic patterns sustaining themselves through survival of the groups they’re in” puzzles.
The penguin/peacock question seems like a case of C, and so even though it involves “groups competing” it’s not what biologists mean by “group selection”.

7. Note that group selection involves variants of genes within a population, with the self-sacrificing cooperative genes finding a way to remain competitive with non-self-sacrificing genes via group expansion.
When the two groups have separate gene pools, as in penguins and peacocks, this is not a question of group selection, just two different species competing for resources.
The similarly comes because both engage in cooperative behaviors, and both are sort of competing at a group level. But note that both the cooperative behaviors, sexually selected tails and food giving, are of Type A rather than Type B. There’s no group selection puzzle here.

Hey, wouldn’t it be nice if you could get an actual evolutionary biologist — an expert, that is — to weigh in here, instead of a lot of “I am not an expert” whoevers? Not condemning their contributions, but I’d like to see something better than guesswork. Maybe send PZ Myers an email? Or ask someone at href=”http://ncse.com/?gclid=CPObkJG0z8oCFcwYHwodY-kIHw”>NCSE?

I forgot to add: The reason that this whole question makes sense only within species involves the question of what happens to a pure-trait group. You might think that it will just benefit, since there is no within-group gain of the non-trait. In any realistic within-species picture, however, there’s substantial genetic exchange with out-groups, so there’s a always a chance of the non-trait gaining within the group.
This also suggests a plausible mechanism for the evolution of auxiliary features stabilizing the trait. Say that the group has evolved anti-out-group behavior (as many do) for unrelated reasons. If the non-trait serves as a marker for out-groupness, then the group is pre-adapted to punish the non-trait. Then all that’s required to get a stable evolution of the group trait going is one little group where it happens to be prevalent by chance.

To calm Theophylact #42, I am a working bacterial eco-evo biologist who has published evolutionary game theory, non-transitive selection,… but, the degree of specialization is serious. I am focused on bacteria. As a result, I find myself caught a tad off guard when I need to think about diploid organisms, for example. Bacteria have more social behaviors than one might think, but many of the common features and questions that evolutionary biologists think about in plants and animals are rather off my radar screen.

As some here have suggested, and others seem to have muddled a bit, group selection is not a synonym for general higher-level selection. Species-level selection must occur but it can’t do the sort of evolution of complex functions that individual level selection can. A few million species for a few million species quasi-generations is just pitiful compared to the numbers of individuals and generations needed to evolve a complex trait like say an eye.

First piece that appeared when I googled Price Equation had what purports to be a gentle introduction to the subject.

http://www.ehudlamm.com/price_eqn.pdf

It seems to me that the question is whether “groups” are actual entities, which the “selfish gene” folks vociferously deny. Are social facts real?

Consider Texas circa 1800: your decendents’ future is totally circumscribed by whether you are an Anglo, a Mexican, or an Apache. It is true that you can ascribe the (evolutionary) benefit of being in a group to individuals … that is, reify the group in terms of individual membership … but it’s simpler to say that the Anglos owned the future and the Apaches did not, for reasons related to the respective cultural resources.

Clearly this retail displacement or genocide of group-on-group behavior has been a big factor in the development of human society as we know it, as it depends on and reinforces social life. That the question even arises must be similar to the discussion about whether typical mammals have emotions … the idea threatens the unique privilege of civilization-as-we-know-it.

Hi John,

I think the answer to your question is (b). One of the best attempts at disentangling the issues surrounding group selection is Samir Okasha’s book, Evolution and the Levels of Selection. Incidentally, he is a colleague of Chris Bertram’s.

I can’t really tell what you’re after, but ch. 7 of his book on species selection might be of help.

Biologists usually think of group selection as an issue WITHIN a given species – think of Darwin’s original example of human morality (groups of humans with individuals willing to die for their fellow group members can out-compete groups that don’t have such individuals). In Sober and Wilson’s framework (Unto Others), they allow that group selection can be at work even if it is not a case of altruism – it is just that the altruism cases are the ones that seem to require group selection.

at any rate, I’d look at Okasha if you haven’t already-

chris

The link that Ronan(rf) gave up there in #33 is worth looking at. It contains a piece by Steven Pinker arguing against group selection and is followed by replies from a number of thinkers, pro and con, with final remarks by Pinker. The respondents include a number of prominent advocates of some version of group selection including DS Wilson, Pete Richardson, Rob Boyd, Herb Gintis, Jonathan Haidt, and of course those against, including Dawkins. I particularly recommend the comments by David Queller (biologist) and Joseph Henrich (anthropologist).

Just because the genetics of races came up, this preprint is apropos.
http://biorxiv.org/content/early/2016/01/15/036822

the extent of condemnation is driven by academic politics more than anything straightforwardly scientific

That was my gut feeling from reading Dawkins (many moons ago).

Just a shout-out to say that George Price’s work seems significant. I don’t know much
about this, or about the history of the subject, but it seems to me that it’s only starting
to get the attention it deserves.

What’s wrong with the example chosen

I gave a long-winded response earlier, so perhaps a more direct answer to the specific question posed would be more user-friendly.

The example as written doesn’t even involve kin selection, much less group selection. The male penguin who feeds his mate thereby increases the survival chances of his own offspring. Society isn’t really involved. The same survival value to feeding one’s better half would exist for survivalist penguins who had gone off the grid, as for penguins with thousands of Facebook friends. (

Okay, a society made up of individual penguin families who all did better because their dad’s didn’t neglect their better halves, would do better than a society of deadbeat dad penguins. Welcome to the libertarian world-view. It’s not a perspective that helps understand anything more complicated than direct, biological, evolutionary advantage. This is the analysis that leads to using evolution to support Social Darwinism.)

The biologists would accept this as an example of just kin selection, if three conditions are met. One is that the altruistic penguins have to gather food for anyone in the group, not just the mothers of their own offspring (if this condition is not met, see last para, we’re talking about direct selection). Two is that the socially useful behavior has to be genetically based. Three is that the group has to share the genetic basis of this socially useful behavior.

We don’t know exactly how the behavior in the example works, but it is inherently unlikely that the specific behavior is hard-wired in the genes, so condition two is not met.

Condition three is not met if condition two is not met. That said, yes, peacocks and penguins are clearly genetically isolated. they’re more than different races, they’re different species, incapable of inter-breeding. If these two behaviors of theirs were both hard-wired in the genes, sure, the survival advantage for the penguin society would be an example of kin selection. While peacock display behavior is perhaps hard-wired, feeding other penguins is almost certainly not, so condition three cannot be met.

All that said, even if this were an example of kin selection, kin selection is it, in terms of biological evolution. The group can only pass on any advantageous trait biologically insofar as it is a kinship, with common genes. What is this group selection of which you speak? What room is there for it in the heaven and earth imagined by the philosophy of the biological sciences?

Why not just admit that group selection is a matter of social rather than biological evolution? All sorts of altruistic behaviors will help one society do better than another, but these behaviors, and their passing on to the next generation, have nothing to do with genetics. Why the impulse to ground an observation that has excellent direct observational evidence in biological evolution? Enough already with the Physics Envy. who cares if the biologists don’t know what you’re talking about, and/or think it’s all stuff and nonsense. Physicists think the same thing about them.

I believe Dr. Hilarius in #10 has the best guidance here. I will add the following.
First, the original notion of group selection was put forth as an answer to why altruism appears to exist in some species. So group selection and altruism are linked in the history of evolutionary biology. It is also essential that one frame the altruism/group selection problem in terms of evolving populations of one species. Otherwise one is more appropriately looking at various population ecology models (interspecific competition, predator-prey, etc.). The original version of group selection maintained that there could exist genes for individual behavior that benefits the group (the population) and hence provide fitness benefits that maintain an altruistic population.

To explain the problem with this, it is useful to define altuism. Altruism in evolutionary biology occurs when an individual provides a fitness benefit to another individual(s) in a population while incurring a fitness cost as a result; the fitness cost (reduced relative reproductive success) is essential in defining biological altruism. From this, the dilemma is immediately clear. A gene for altruism would not survive in the face of selfish genes; altruistic genes would be at a relative fitness disadvantage in the the population and individuals with those genotypes and phenotypes would decline in frequency.

To explain altruism, the most common approach is Hamilton’s rule which expresses the costs-benefits of altruism as: C = rB. r = coefficient of relatedness, B is benefit from the altruistic behavior, C is the cost. So rB > C is required for altruism to succeed as an evolutionary strategy. This approach is also referred to as kin selection. This model is the workhorse for analysts working in the areas of cooperation and altruism in evolutionary biology. It also explains the phenomena without resort to group selection.

David Sloan Wilson has other ideas. He and some others (including the esteemed EO Wilson, no relation) maintain that a type of group selection can be saved by using what they refer to as multilevel selection theory. This maintains that the force of selection can act on units besides individuals(genes) within a population. Roughly, it maintains that if the strength of selection on different, separate populations is high enough relative to the strength of selection within a population, then it may be that group selection can occur. For one discussion of this, see Samir Okasha, Multi-level selection, Price’s Equation, and Causality. It puts the theory in terms of the Price equation, which is interesting. You might also look at an old paper by Richard Lewontin (The Units of Selection). Note, though, that this is a distinctly minority position within this field. I believe (may be wrong here) that most analysts would say the likelihood of the type of group selection referred to by the two Wilsons etc. is very unlikely as an empirical matter. Morever, it is maintained that once this small empirical likelihood is granted, multilevel selection theory doesn’t added anything beyond what the kin selection framework already provides.

Personally, when I read this literature, I got the impression that these two approaches looked at the same phenomenon from two different perspectives. The first from the gene-level, the second from the nature of the forces of selection and what biological units are selected and when. Each is interesting. I also got the impression the group selection analysts made claims in criticism of kin selection analysis that were probably off-base.

“Personally, when I read this literature, I got the impression that these two approaches looked at the same phenomenon from two different perspectives.”

Both Henrich and Queller (among others) speak to this in the Pinker symposium Ronan(rf) linked to in #33.

Although Pinker is neither a neuroscientist nor a population geneticist, his piece has been highly praised as a useful corrective to the misapprehensions of group selectionists. So it is useful to highlight some remarks from it.

“But other extensions are so poetical that they shed no light on the phenomenon and only obscure the real power of natural selection.”

Both the handful of group selectionists and their opponents share a commitment to genetic determinism of human behavioral traits. Some like Coyne and Pinker have agree with the likes of Nicholas Wade that “races” are biological reality, though of course they vigorously deny this implies racism. The rest of us should be skeptical of all parties. These are the kind of people who believe in evolutionary psychology. But in addition to being genetic determinists, the larger part of them oppose group selection because they are panselectionists, that is, every trait is deemed to be adaptive. They may not have Paley’s God, but Evolution has its Natural Theology. That too they will vigorously deny when caught at it, but in practice I’ve never found them even considering limits to the power of natural selection.

“Except in the theoretically possible but empirically unlikely circumstance in which groups bud off new groups faster than their members have babies, any genetic tendency to risk life and limb that results in a net decrease in individual inclusive fitness will be relentlessly selected against. A new mutation with this effect would not come to predominate in the population, and even if it did, it would be driven out by any immigrant or mutant that favored itself at the expense of the group.”

I do not know how these people know that natural selection is not just relentless but effective. But it is explicit here that it is the unfailing power of natural selection that prevents the emergence of individually deleterious traits and its spread to predominate in a group. I see two basic problems here.

Less importantly, kin selection, even when it is more discreetly renamed inclusive fitness, makes no sense as a display of the power of natural selection to weed out negative traits, even assuming genetic determinism. It makes much more sense to say that an episodically or contingently or randomly negative trait cannot be weeded out of a population because the genes prerequisite for the trait are still carried by the kin. But this is definitional/conceptual, and I suppose confusionism in such matters is acceptable.

More importantly, the implication that groups cannot replicate faster than the members have babies is more or less nuts when you’re talking about people. Human groups fission and fuse with bewildering speed, changing the genetic compositions of the groups. Personally I should think such nonsense is like a small turd in a large punch bowl: It’s quite enough to ruin it all.

“Compared to the way people treat nonrelatives, they are far more likely to feed their relatives, nurture them, do them favors, live near them, take risks to protect them, avoid hurting them, back away from fights with them, donate organs to them, and leave them inheritances.” And…Women are from Venus, Men are from Mars. Incidentally, it’s not so clear, except to those who insist on the power of natural selection, that the variety in human beings, on a genetic level, is comparable to the variety in other longer extant species. But as one readily sees, you could exchange “nonrelatives” for “strangers” and “neighbors” for “relatives,” and this statement would be just as true…because it is just as vacuous.

At any rate, mating is usually carried out with non-relatives. It is not clear how natural selection can produce behaviors that favor kin rather than strangers, except when they might turn out to be mates (and maybe offspring who will become kin) without some kind of prophetic power. It’s rather like people spontaneously, without reward, trying to help strangers’ children because of inclusive fitness, as opposed to adopted children. But enough, Pinker is very slick and it takes much more effort to explain the tricks than for him to do them.

The remarkable thing is, though Pinker has a background in linguistics, he has nothing to say about language, possibly because this is a group trait. Personally, being neither a genetic determinist nor a panselectionist, I don’t think group selection is as determinative of human culture as sexual selection is in male and female personality according to evolutionary psychology. But as an explanation for the emergence of something like language, something you might call human nature rather than culture (way of life,) group selection so far as I know is a reasonable candidate. At this point, it seems to me likely it is the only significant genetically determined behavior.

On Wilson, Nowak, Tarnita: That whole paper and dust-up was a sad event. One point of the paper was that the original bar-napkin version of kin selection was an approximation only valid in a smallish range of parameter space, and that typical teaching didn’t emphasize that. It would be as if we taught that all fluids are ideal gases. Good point.
The rest of the paper was a philosophical disaster, in which they basically claimed that if you wrote down a tautological expression “exact fitness=exact fitness” you’d made an important scientific claim.

Hi John,

I’ve been trying to get my head around it too, and it seems to me that there are a few different issue being conflated, which leads to people talking past each other. A thought, which I hope is helpful:

I think that the emphasis on co-operation is partially because this is needed for a group to exist in any useful sense. ‘Sociability’ might be a better (broader, less loaded) term. So I agree with some others here that the comparison between penguins and peacocks seems like competition between two strategies, not two groups in the relevant sense – even though both strategies in your example do involve reciprocal behaviour within ‘groups’. Group selection is about groups as entities (*or something like that* – again, people seem to talk past each other a bit). My go-to example is a case of a species which has two cultures – some groups are stag hunters, some are hare hunters, and the groups are competing as teams for other resources like water etc. There are so many ways that the situation (imaginably) can go from here – stag hunters learn to cooperate in other ways on the basis of their acquire stag hunting skills, or periodically become too successful for their own good and wipe out their prey, or the two groups diverge from each other toward speciation… But perhaps the key question is, whether the groups themselves can survive in a substantial enough sense for us to see them as entities with a genealogy.

Your example behaviors revolve around sex, but you have not seemed to think it necessary to think about how sexual reproduction affects the problem of variation in descent. No individual is simply reproducing herself from one generation to the next.

There is a gene pool, mixing in the gene pool, and so on. One of the advantages of sexual reproduction is, paradoxically, that it resists the elimination of variations that presently confer no advantage. The gene pool, with mixing, is being reproduced from one generation to the next, but even environmental conditions that last several generations will not necessarily eliminate variation with no current fit to those environmental conditions. The potential remains, perhaps hiding as a recessive trait.

The sexually reproducing species has the advantage that it retains this latent fitness, and can manifest it as adaptability in response to sudden shocks. A time of strong selection in relation to one particular challenge from the environment is not enough to impose a rigid homogeneity on species potential.

This is group selection in the sense that variation in the gene pool is enabling the species to survive environmental shocks. But, it is variation in the pool, not a particular shared and defining characteristic shared among representatives of the species, that enables survival.

It ought to be noted that, in the anthropocene era, group selection may have become a dominant influence when humans hunted various species into extinction and marginalized others through competition and habitat alteration. Where are the charismatic megafauna of yesteryear?

Until someone can propose a falsifying experiment, this whole discussion is about something other then science

this suggests a test: altruistic acts (a bee stinging an invader, and dying, to protect the queen) are determined by the genetic relatedness of the altruistic person

Relying on average/normalize/global fitness is a grave problem with many models. Particularly in game theoretic treatments, it is undesirable. Dealing with finite, particularly structured, populations requires different approaches. Moving to graphs is one extreme (a la Lieberman, Hauert, and Nowak 2005; but also Adami, or Kerr, in many publications). Anyway, many relevant studies about cooperation, cheating, non-transitive fitness, and so on have progressed beyond global fitness/average payoff.

Very interesting discussion thanks.

At the risk of making an idiot of myself.

Two groups of creatures are identical in every way except in one all individuals are entirely selfish and only look after themselves while the others are altruistic and look out for each other.

A catastrophe comes and survival can only be achieved for a proportion of the group if they co-operate and some individuals accept they risk of, and/or will definitely loose their lives, for the survival of the remainder of the group.

The selfish individuals of the first group can’t do that and they all die. The altruistic members of the second group can do that and so some survive.

I don’t quite see how the framework of the Price equation would yield an explanation, as opposed to a way to concisely express the consequences of an explanation. (Or maybe I’m expecting too much: the same might be said for Newton’s laws of motion.)

Also: whether or not it sits under the heading of the biology topic of “group selection”, the setup in the OP still raises a question that I haven’t noticed a direct answer for: why wouldn’t the “useful” male penguin reproduction strategy always outperform the”wasteful” peacock strategy, and drive it out? That is, why do we observe peacocks at all, in the sense of “male birds using expensive displays to attract females”?

Along similar lines, males do not produce children, and so the resources consumed by them are not going into the next generation, which would arise faster without them. So: why aren’t males tiny? Maybe the situation of herd animals amounts to this: one male becomes “herd bull”, and fathers most of the herd offspring, while the losing males wander off and, without herd protection, die. So the resources consumed by males are less than those devoted to females, which is advantageous for the species.

Kiwanda @ 86

why wouldn’t the “useful” male penguin reproduction strategy always outperform the”wasteful” peacock strategy, and drive it out.

Because food isn’t always the constraint. If selection pressure comes from parasites, but food is abundant, the “look how healthy I am” strategy of peacocks is better.

The question group selection tries to answer (as I understand it) is how is it that you see both strategies in the same species, when one is clearly better for several generations at a time.

I’m going to throw in one more article in the possibility that it will be helpful:

http://biorxiv.org/content/early/2016/02/01/038505

Cooperation is encouraged by spatial structure (localism, anyone?)…

Just wondered – how do things like slime molds, where the group is basically the only thing that has the sorts of properties that could be the object of selection, fit into this?

by the way

As far as I understand, most people reject group selection because it is mathematically virtually impossible…

“Mathematically virtually impossible” means “impossible within a model”, so the word “mathematically” is adding less here than you might think.

The Hadza hunter-gatherer groups, noe of the very few remaining, split up and rejoin every few weeks. The individuals select which group they want to be in, and you can leave anytime you want, if you find someone willing to take you in. You can imagine people fighting to be with people who have an altruistic and successful reputation, and since there is a limit, the altruistic are more likely to find each other and have more opportunity to succeed and breed.

I do not think the “problem” or “question” has been well formed. Is gene selection occurring at the genetic, individual, kin, group, species, or planetary level? The genes are only a memory of what chemical interactions exploit energy resources the fastest, emitting as much entropy as possible to the universe. Genes do not exert forces of their own accord, but exist as a result of what the environment forces. In the genes only appear selfish because of what the environment forces with potentials, I question if there are any other forces from the genetic all the way to the planetary level that can or should be viewed as either selfish or altruistic. This is assigning thought as a force as if it is independent of potential and kinetic energy sources which are the only cause of all forces. Thought is a physical process subject to dynamics like everything else, not something mystical. The environment is following the physical potential gradients that release heat and thereby entropy to the universe. The moon might be the pre-existing order that makes Earth different, giving rise to tidal flows where some of the earliest life is known to have lived, and giving rise to a constantly-churning mantel that gives rise to ore concentrations and veins that modern economies depend on. The odd tilt of the earth’s axis, also probably a result of the collision that created the moon gives rises to seasons and wind complexities which are another source of decreased entropy compared to Mars et al. So not only the Sun’s energy, but the moon’s lower-entropy may be giving rise to life (it’s mere existence is like a gas constantly having more molecules forced to one side of a box which is lower entropy).

This is why everything above appears vacuous. There is not any terminology being used in the discussion that I can grab on to and falsify or subject to observation. It’s like trying to argue about the old and discredited mind-body problem. The mind is a result the body. Selection is the result of the flow of energy, not a force in and of itself.