I am abrupt in my dismissal: I see no evidence nor plausible mechanism for group selection, and I don’t even understand why some scientists continue to insist it had to have happened, other than a fondness for some kind of vague deus ex machina to reach down and smooth over the indirect and inefficient mechanisms that can produce altruism and properties of populations. And discomfort with the fact that evolution is weirder and less straightforward than our brains can imagine is not an argument for endorsing wishful thinking.
Jerry Coyne rips into the latest eruption of group selectionism. Go there for the details.
(Also on Sb)
I’ve always had the vague sense that proponents of group selection are doing so with ulterior political motives. Once the ‘group’ becomes the focal point of the equation, the relative moral importance of any individual decreases. Of course, I’m not a scientist, so I admit I have my own political bias here.
Take two groups of humans, who may or may not be competing for the same resources. One group has mostly cooperative individuals, the other mostly selfish folk. For humans, individually weak, & without claws & fangs, cooperation seems to give the best chance for survival.
So the genes that promote cooperation spread into the sub-groups that descend from the original cooperative group. And then other slight adaptations occur, contingent upon enhanced cooperation.
Isn’t that selection at the level of the group?
The thing is… I can sort of see how group selection might exist. I don’t really have a problem with that. At the moment though, I don’t see a reason to assume that it does indeed exist. It certainly doesn’t seem to be a major or widespread phenomenon.
“Isn’t that selection at the level of the group?”
Yeah, that’s how I see group selection as a possible mechanism too. The question to me is how much something like that has contributed to evolutionary history.
Dick the Damned
But is the situation you describe there actually going to happen in nature? It seems odd to even talk about “groups” when you don’t have cooperative individuals… what exactly is keeping them as a group?
It’s not that one group has no cooperative individuals, it’s that there is just a greater degree of cooperation exists in one group than in another. I’m no expert, and I can’t really think of an example off hand, but such a thing isn’t beyond imagination. I can see it happen, sort of. (I would like to add that I’m not an advocate of groups selection per se, but I do think the case against it is often somewhat overstated.)
Sure, but as far as I understand,(and my only source is The Selfish Gene) the amount of cooperative and uncooperative individuals in an society would settle into an equilibrium.
Now, if your argument is that non-biological and situational factors which populations share – such as ideologies, political systems, technologies, etc, play a role in shaping evolution, I don’t think anyone would deny that. But there’s no genetic basis for those (though certainly a memetic basis).
municipalis
Just to clarify here: I meant survival, not evolution.
Um I’m a novice here, but you’re running against a basic problem here: the individual gene that promotes cooperation (or its variant that promotes more cooperation) will only spread within a group if that is beneficial to the individual who holds it. Competition between genetically different nonmixing groups is ordinary population genetics (not a new type of selection), isn’t it?
Well I don’t really understand the issue people have with group selection. Selection happens at any organizational level in which there is greater variation in phenotype, the variation is heritable, and some phenotypes do better – period. Group selection happens.
Cultural groups are under selection, just as individuals are.
If it helps you can ignore altruism/cooperation, it doesnt really matter. Take for example 2 groups of organisms, both living in the same region sharing the same eviornment etc. The individuals that make up each group all have a relative fitness of 1. In fact there is 0 variation among the expected value of fitness within the groups. However group A has developed a fancy new dance that entices members of group B over to join A. Depending on the change over rate between the groups group A will eventually take over the region, either by completely converting all of group B, or by drift impacting the shrinking population size of B. Selection: – happening at the group level.
Indeed. All too often discussions on group selection get completely stuck on the whole ‘altruism’ thing.
dave1
But on what biological basis are you defining the differences between the two groups? If there’s a gene for better dancing, then the ‘takeover’ will be determined by the rate at which the gene is introduced into individuals who can then dance better.
Dancing is just a cultural trait that any individual in both groups may posses due to whatever genes are acting that allow for the formation and transmission of culture. There is no relevent biological differences between the individuals that make up the group. – Thus the expected relative fitness of every individual in the entire region is 1. The fact that group A will eventualy produce more offspring is strictly determined by the population sizes of each group.
dave1
But if there is no relevant biological difference… then nothing is really evolving, is it? You just have two group with slightly different cultures becoming one group with a single culture. It’s really a tautology: Are Canadians turning into Americans because we consume more and more American culture? Well, maybe, but only if your definition of “American” is someone who consumes American culture. I certainly agree with you that political and cultural factors influence sexual selection, but I’m just arguing that there is no end biological result. There’s no guarantee that the children of the “cool kids” will be more likely to turn into “cool kids”.
And I should add – returning to the topic of altruism – that there does seem to be a genetic basis for altruism; the kids of altruistic kids are more likely to be be altruistic themselves. But that genetic determination occurs on the individual level, not as a group block.
Another example of group selection that I like is that of the sex ratio in fig wasps. Granted it has been years since I have looked at the data, so new research may have changed our understanding of this system…
Essentially female fig wasps lay eggs inside figs(1 or more female), the eggs hatch and develop, and mate within the fig. The female offspring then disperse to new figs. I will try to diagram it for better clarity. Each column represnts a fig, each with 8 offspring of a given sex.
| F M | | F M | | F F |
| F M | | F M | | F F |
| F M | | M M | | F M |
| F M | | M M | | F M |
In the first fig there is a 50/50 sex ratio, totaling 4 dispersing wasps. In the second fig there is a male biased ratio of 3m/1f, with 2 dispersing wasps. In the final fig there is a female biased ratio, of 1m/3f, with 6 dispersing wasps.
In the second fig it is better to be female than male: all females will reproduce, not all males will. In the third fig males have a higher average fitness, those 2 males on average are passing on their genes to 3 females. There are then 6 females who will disperse and pass on the genes.
Selection is favoring a female biased sex ratio at the level of ‘fig’:group selection – due to the higher number of dispersers in fig 3.
However selection at the individual level within each fig favors the rarer sex, like most populations. If I am a male in fig 3, I do better on average than a female. Essentially without modeling the evolution of sex ratios the # of grandchildren is what matters. To maximize # of grandchildren you produce the rarer sex. This pushes populations close to a 50/50 ratio.
If these wasps mated outside of the closed fig environments, then the sex ratio would be close to 50/50, as it stands the last time I looked the actual ratio is close to 70/30 female bias.
dave1:
I’m not sure what you’re trying to get at here. What you’ve described is just an example of an evolutionary stable state. No one is arguing that outside factors which affect groups do not play a role in who survives/breeds and who does not. The argument against group selection is that these factors fundamentally affect individual survival/breeding chances, not group ones.
This is my first time posting here after years of lurking so I dont know how to quote.
There can be significant biological change in my cultural group example. Any one of the individuals that make up the population can have a ton of variation, what matters is that the selective pressure guiding the system acted on the variation at the group level, all of the other variation within the individual level may be acted on when the envoirnment changes, or be subjected to drift.
If all that happens in this situation is the entire population joined group A, they yes, nothing at the momment changes biologically, but culurally. However, if not everyone moves to group A then those left in group B would likly die out if the population size became small due to all of the stochasic effects that impact smaller populations.
The fig example shows that selection acting on the group level – alters the sex ratio of the wasps. Im not saying that selection at the individual level does not happen, or that this fact doesnt impact what happens at the individual level.
Variation at whatever level can impact the direction a population evolves. By stating it all effects the individual is true, but it’s really semantics, individuals do not evolve, populations do. What needs to be examined is at what organizational level selection is acting on.
In the fig wasp example if group selection was not taken into account the population dynamics could not be understood.
OK, so can I have a concrete definition of group selection? I’ve never been exactly sure what it means on a mechanical level, because every time I try to find out there seems to be more heat than light on the subject.
Specifically, does the concept apply only to monospecific groups? Because if not, symbiotic groups (e.g. microbial consortia) would seem to qualify. Or do we just pretend that such a group is an individual and go about our usual non-group-selectionist business?
Err… the Price equation’s covariance term? Though I’m probably misunderstanding the jargon for what biologists mean by “group selection”.
dave1:
I’m fully in favour of inquiries along this path (in fact, I believe it’s called “sociology”), but the point remains that there is no biological mechanism which acts on the group level.
Let’s keep our eye on the ball: the reason why altruism is always brought up in such debates is because the argument is over whether there exists a biological mechanism which favours groups of individuals rather than individuals acting alone.
The Group Selection proponents argue that altruism cannot have a solely individual basis because (by definition) altruism requires individuals to make sacrifices which reduce their individual breed/survive chances. This nullifies the theory of “the selfish gene” since people are giving up on their own biological imperatives. Therefore, in order for that concept to have evolved genetically, there must exist a different model of selection which favours the survival of the group rather than just the survival of the individual.
Nowadays, a very small minority of biologists cling to this view, and for good reason. 1) no one has been able to successfully identify the mechanism by which this group selection occurs, and 2) very plausible explanations exist for the existence of this phenomenon on the individual-selection level.
Seriously, if you haven’t already, read The Selfish Gene. It’s superbly written, and goes over all these arguments with far better clarity and knowledge than I’m able to muster.
Mechanistically selection is selection. Prefacing the word selection with an organizational term helps define the factors that are influencing whatever population or system you are studying.
Again, selection acts on variation, whatever level of organization that contains heritable variation and differential reproduction casually determined by that variation will undergo selection. Peroid.
The combination of selection acting at all levels influences the direction populations evolve. At the genomic level, cellular level, individual level, and group level. At each one of these organizational levels ‘reproduction’ happens at a different rate, not all at once at the individual level. IF the reproductive rate of all of these systems was exactly the same then I would argue against multiple levels of selection, but that is not the case.
My understanding of a genetic basis for altruism is that until very recently in human history we lived in small groups where pretty much everyone was related to each other. Thus acting selflessly to help others in the group would help the genes you have in common reproduce.
The fact we see people acting altruisticly to help those who are not related to themselves is simply because our genes have not yet caught up with the fact we know live in far larger groups.
The problem you have is that group selection is not required as an explanation. It is an added complication that does nothing to further understanding. None the examples given here of supposed group selection cannot be explained using gene level selection.
dave1
Again, this is a debate about the specific mechanism of natural selection, not about which factors affect it.
It’s completely obvious to say that different genetic, demographical, sociological, political, economic, etc. configurations of groups will produce different results. The key is that, given a long enough time period, success is determined solely at the genetic level; survival is determined by the adaptive fitness provided by an individual’s genes.
Pff, this story was way better.
Dave, you can assert as many Periods as you want, but the plain fact is that there are no known examples of real-world biology for which group-selection is a necessary cause. Individual-level selection is always more powerful and more important if both favor similar behavior, so the only interesting cases are where group selection has produced adaptations that individual (or kin) selection cannot. Zero cases are known.
I just gave 2 examples in which selection acting on the level of the group can alter the direction the populations evolve. The key point that everyone seems to miss is where the variation is coming from. Multilevel selection is not a seperate mechanic, it is (and should be defined) as selection acting on organizational levels other than the individual.
Which two examples ? Not the wasps, nor altruism I trust since it has already been explained to you how those are not examples of group level selection.
dave1
In all of your examples, the significant determinant of selection was the fitness of individual genetics to adapt to an external situation. In none of your examples was there a contradiction between survival and individual genetic selection.
Dave,
In short what you do not seem to understand is that gene-level selection is sufficient to explain the apparent selection involving higher levels. Since some selection cannot be explained using any other mechanism than gene-level selection it follows that introducing other levels of selection adds an unnecessary degree of complication. Gene selection is a mechanism, and it follows that if you want to invoke other levels of selection they too much be considered as mechanisms and require an explanation as to how they operate.
As I said, the mechanics of selection are the same regardless what system you look at- biological or not.
I’ll try to address a few points.
First, I don’t mention altruism in any example. A fixation on altruism/cooperation as poster child for group selection is questionable.
Second, my example for group selection at the cultural level is valid as the genetics governing the ability to use and transmit cultural ideas do not create the ideas themselves. Genes != Culture. The variation in the system (in my example) happens at a greater ordering than that of the individual.
In the wasp example yes there is an equalibrium in reproductive strategy, and the reason why it is different is due to the effect of breeding strategies by the individuals. The breeding strategy creates self enclosed groups of breeders. It is selection acting both within and between these groups that is altering the final distribution. Selection at the level of figs favors wasps that produce more females, not at the individual level.
This shouldnt be hard to understand.
Wouldn’t a simpson’s paradox-like situation provide a way for group selection to work. I mean, within each group a trait like altruism would decrease in frequency (because of individual/gene selection), but in the population as a whole it could turn out that altruism will increase in frequency (group selection). Just throwing out an idea, here.
dave1:
No, they are not the same. Genetic material persists throughout the genealogy of the organism. Your genes get passed on, and you have no control over them. Your culture, your environment, your religion are all arbitrary and can be changed. You may try and pass them onto your children, but there’s no guarantee. Genetic material is the fundamental determinant here – the environmental and social landscapes are just where they play out.
Ideas do not just pop into existence. Social structures do not pop into existence. If you go far enough back, they are created by individuals, who take their cues from their respective genetic advantages.
No. More females are produced because that is the optimal state for individuals to pass on their genes. It’s very simple: if there are two egg-laying females and one produces a ratio of X:Y males:femals offspring, and the other Z:A, one of these strategies will be more successful than the other, based on the environmental factors at play. At the end of the day, you could say the group benefits because there’s “more” of it – but that’s not what really counts. The key factor – once again – is individual genetics.
pentatomid,
That is exactly what happens in some models for altruism.
Here is one simple example:
AASS Group of 4 individuals, 2A, 2S – freq of A = .5, freq of S = .5
In the next gen alts do ok, but S do better end up AAASSSS – freq A = 3/7 ,freq S = 4/7
Eventually A will go extinct.
If you add in groups that may not be the case
(AASS) (SSSS) (SSSS) : freq A = 1/6
next gen – groups with A’s do a little better
(AAASSSS) (SSSS) (SSSS): freq A = 1/5
So in this case, while within the group the freq of alts went down, if you look at the population comprised of the groups it actually went up. In this simple example it is again the variation between the groups that matters.
Also, I forgot to address:
dave1:
Do you really not understand why? I explained above (at 22) why the altruism argument is so key. Did you read that? Very simply: in order to show group selection as valid, you have to show a case where the “selfish gene” cannot account for the existence of genetic material. Altruism – where people do things which helps others survive against their own survival – is seen (wrongly) as such a case.
Genetic material may the ‘fundamental’ material or whatever, but you mistake the fact that culture ‘may not’ get passed from one generation to the next for ‘does not’. Culture can be passed both vertically and horizontally. Just because it ‘may’ not is meaningless. Its the fact that it CAN and does that is important.
It is also meaningless to say that the culture was created by genes in the past, sure thats the case, but it doesnt matter. What matters is how a cultural phenotype that may not be governed by indivdual genotypes can alter the direction the population evolves.
The enviornmental factors that you dismiss are what determines whether or not selection is more prevalent at the group or individual level. Again, yes the individuals have different breeding strategies: what makes them more ‘ideal’ is how selection acts on them. In the case of the fig wasps, selection at the level of the group is an important factor in that.
Oh jesus fucking christ.
@dave1 #36
And how does not the following apply in your three group example?
Or in other words, jesus fucking Christ…
dave1
Good, then we are in agreement: selection is at an individual genetic basis.
No. Culture is determined, at a fundamental and historical level, by the interaction of genetic individuals. The ability of individuals to perform to the expectations of culture is also genetically determined.
No. It matters because we are arguing whether the fundamental vehicle for evolution is or is not on the individual level. You have just admitted it is not.
Random environmental factors is the field upon which non-random genetic material is tested. You cannot have evolution without such a field because there would be no pressure for genetic adaptation. Genetic adaptation happens only at the individual level!
municipalis
Ugh, that should read “You have just admitted it IS”.
Anyway, dave1, it is apparent that you do not quite understand the difference between group and individual selection. It is simple: if it all boils down to genes, then you have individual selection. If there is a case where individual selection does not make sense – is contradictory to what is happening – then you have to have another mechanism, such as group selection.
The simplistic example of altruism was used to highlight the exact case that pentatomid was asking about no more It doesnt matter if altruism is in fact an example of group selection or not.
Mathmatically it follows a kin selection model.
WS = Avg fitness of selfish ind
WA = Avg fitness of Alt
B = Benefit to recipient of altruistic act
C = cost to altruist
r = probability that the other individual is also an altruist (relatedness)
N = number of others in a group
WS ≈ fitness in groups/families with no altruists
WA ≈ WS –CN + BrN
WA>WS if BrN-CN>0
Alts can increase in freq if Br>C
I think the problem here is what you define selection as. Selection is selection is selection. It is all one process. The point I am trying to get across, and missing, is that this process occurs at discrete organization levels based on the variation at those levels. It is through a combined net effect of various levels of selection that ultimatly determine which way that population will move, (plus all of the other momments of the distribution).
Perhaps you are right, and I don’t know what you mean by group selection. However the way I have defined it is both meaningful and useful to the study of evolution.
dave1
So, what you’re saying is something like Wilson and Sober’s multilevel selection theory, right?
There may be some confusion in the comments between group selection and kin selection. They are not the same thing. Group selection, as understood in biology, by biologists, simply does not happen. Ideosyncratic definitions of group selection are useless in the context of the definition as used in the field and as put forth most recently by Martin Nowak et al. in Nature in 2010. The reality is that no plausible mechanism exists for such a thing as group selection and that group selection does not occur.
dave1:
Yes, see – I’m not arguing as to what the factors of selection are – I’m arguing what the mechanism is. The factors are environmental, the mechanism is the gene. Genetic mutations are random, but environmental factors are not. The end result is that the random fitness of an individuals genes determine the likelihood of that person surviving and passing down their genes. If the factors change, so too will the individuals who survive – but the mechanism remains the same.
As I tried to tell you, those ‘organizational levels’ (I’m hesitant to call them discreet, but they may be) are the playing field; the factors upon which the fitness of an individuals genes are tested.
Of course, as I said above, “You cannot have evolution without such a field [your ‘levels’] because there would be no pressure for genetic adaptation”. But that doesn’t refute that the effect is on genetic individuals rather than groups.
What you’re advocating is essentially the study of how different environmental factors affect genetic success. That’s essentially what the field of population genetics does. And as you move further and further away from a strictly biological understanding, you enter the fields of the social sciences. I completely agree that this is “meaningful and useful”, but it has nothing to do with the validity of the theory of group selection.
No it is not. This I think is where you are going wrong. Gene level selection is not the same as individual level selection which is not the same as group level selection.
However, since you are so convinced that group level selection is real I think it is time you offered an example that cannot be explained using gene level selection.
As Municipalis correctly points out you are confusing environmental factors that influence evolutionary selection with group selection.
As Thomathy points out you also seem to be confusing kin selection (which is explainable as the result of gene level selection) with group selection. Group selection is not the same as group selection. By defintion group selection cannot use the same mechanism as kin level (and thus gene level) selection, since part of the definition of group level selection is that it is not kin selection. So you really do need to offer up a mechanism by which group selection can happen, since your argument the mechanisms are the same for all levels of selection is wrong. The fact you refuse to accept that is getting rather tedious.
I would also suggest you read “The Selfish Gene”.
Altruism confers social status, thus individuals with more altruism mate more, and with other desirable and high standing individuals.
I’m not sure of the integrity of some studies I’ve seen reported at Sciencedaily lately, but one shows that females find altruism more attractive, and another shows that higher standing males act as peacemakers in primate populations. Oh, chimpanzees:
It seems to me that being able to trust an individual is a highly valued trait that confers security and reliable co-operation to the others in a social group.
Competing tribes would incorporate helpful and peaceful, and loyal, individuals from conquered tribes, securing individual chance for survival by integration into victorious groups(although I can see some problems with this idea), and more peaceful and co-operative groups as a whole would tend to form trust and loyalties with other groups/tribes which becomes a numerical advantage against more ruthless and isolated groups/tribes.
Also, individuals have a greater chance of survival through sharing of wealth(food, shelter), protection, and division into specialized, and therefore, more productive units operating as parts of the whole group.
Individuals need empathy to understand and anticipate needs and wants of others, and my own experiences of being highly valued, and popular, in workplaces and other groups, due to my own ability to relate to and understand others – and thus, anticipate and stay ‘one steps ahead of the game – is, it seems to me, a powerful force in promoting individual well being. The fact that I am willing to share, and extend trust and respect to others also actualizes into a lot of safety for me. I live in the most dangerous and violent part of the city here in Edmonton, and I am in no way equipped to compete on an individual level, but I enjoy relative safety just because so many people around here will come to my aid when others threaten me.
Without a doubt, the safety of mutual respect between people that treat others with understanding and assertiveness (and are willing to get involved in unfairly matched situations, and settle things down, and stand up for others) earns respect and loyalty like nothing else. Even in situation where I am one of the perceived repressive group in authority, I get less anger and threats directed my way, and just because I am known, and present, leads to an reduction in tension and even individuals in the unruly groups have made efforts to ‘see things my way’ and coerce others in their group. At the least, I am sort of left out as a target of their anger or fear.
This is very highly anecdotal and prone to my biases in interpretation, but leaders that display compassion and sacrifice are far more effective at inspiring loyalty, and also this happens between individual relationships with others that establishes an over-all cohesion. Even arrogance and narcissism don’t inspire long term commitment in others, although initially they may be respected and followed.
Sorry for the long post, I don’t even know if I’m making sense (half the time I don’t!), but it seems very plain to me that empathy, compassion, and altruism are crucial ingredients in the ability to form societies. In fact, I think that now this IS a selective force that will determine the survival of humanity because rogue individuals and groups/governments now can get disproportionate power in the hands of a few, and the less threatened, and more understood they feel, the less likely they are to act aggressively and mutually destructive.
So, if group selection isn’t happening, I’ll be a monkey’s uncle!
PS Ooops, I can’t find links to the study, or studies, where first year college and university students found altruism more attractive than wealth, but does seem to obtain, all else being equal, on campuses, LOL
mikelaing,
You are simply describing altruism which does not require group selection to explain it. This has already be explained repeatedly.
Please go an read “The Selfish Gene”.
IIRC, group selection has been formulated as a perfectly cromulent model…it may be strong enough to overcome selection acting on the individual if generation time is short enough and if mating groups are ephemeral. I don’t know if that model was successfully applied to either Dictyostelium or to some type of sea urchin, but I read some shit about this not long ago…must get to school and look it up.
Matt Penfold 51,
Yes, I found a copy online and started to read. Chapter 13 is the one to read, and the more I read, the more embarrassed I felt!
Although it still seems slightly arbitrary to me, as far as extended phenotype is explained, I understand what is meant. One problem, I think, is Dawkin’s choice of the word ‘replicator’ when ‘replicater’ would be more grammatically intuitive. i certainly am able to see the expression of altruism as a means to an end for a gene, or whatever unit is responsible, but it still relies on the survival of the group to ensure replication.
He still has some serious difficulties to overcome. I don’t have time, at the moment, but I will get back in a couple of hours to explain them.
So, I was remembering a review article by Egbert Leigh from 2010, Titled “The Group Selection Controversy” (J . EVOL. BIOL. 23 6–19). Especially informative to this discussion might be the section called Can group selection override selection within groups?
dave1:
Yeah. This. Selection can be generally modeled as differential reproductive success of non-identical sets of replicators*. How we define (or identify these sets) constitutes the hypothesis of selection that we are testing. There is no reason to think that there is a “unit of selection” generalizeable to all instances; this isn’t to say that some sets of replicators (the genome, for instance) aren’t often the target of selection and therefore the target of explanatory hypotheses. And as dave1 explains, contributing forces of selection in reality may be functioning simultaneously on different levels.
*replicaters
I just wiped out a great windy post extolling group selection. I am wrong. It is at the individual, selfish level. Even altruism is a means of gaining survival for the individual.
Man, I’m not sure. On the one hand, the altruism replicator is only relevant at the group and intergroup level, and the ability to proliferate – generate more copies – is enhanced through co-operation, so an altruism gene is self enhancing that way. Yet, the group isn’t quite a bottle-necked life cycle for the gene, although it Can BE.
But, having co-operative and caring individuals and groups around is still a method of individuals looking to protect their own viability.
Yes, then altruism gene weakens the individual because one that is reliant on others beyond its physical control is still more vulnerable overall. Sort of like the altruism gene is parasitical. It weakens the host at the individual level. Sigh…
Probably the best argument I’ve heard towards there being (some) group selection was by Samir Okasha:
http://www2.lse.ac.uk/newsAndMedia/videoAndAudio/channels/publicLecturesAndEvents/player.aspx?id=646
https://www.bris.ac.uk/philosophy/department/staff/so/compass
You need to look at it from a gene level, not the level of an individual.
Historically humans have lived in small groups of no more than around 150 individuals. Most of those individual will be related to each other, so that they will share a large number of genes in common. An altruistic act in such a situation will very probably benefit individuals who share a lot of genes with the individual performing the act. The act may harm the chances of reproductive success for the person performing the act, but if the reproductive chances of the individuals benefiting from the act are improved, then it can be shown that altruism can be selected for without needing to invoke anything other than gene level selection.
One would predict from such this that the prevalence of altruistic acts will correlate with how closely related are the individual carrying out the act and the beneficiaries. This is in fact what we find. We might also consider the chances of an older individual performing an altruistic act would be greater than that of a younger individual. Again, this is what is found.
Maybe this has been addressed and I’ve missed it, I’ve only skimmed through most of the comments, but I’ve never been able to see how group selection (in most circumstances, at least) can overcome a fundamental problem which IIRC I read in the Blind Watchmaker.
It occurs to me it’s basically similar to the Free Rider problem in Economics, you have your group with many individuals performing self-sacrificing acts which enhance the survival and growth of the group (which eventually spawns off daughter groups), it seems to work. But then what happens when a more selfish individual is born? They will get all of the benefits of the relatively selfless nature of the group, but with no personal costs. It seems this would negate any benefit to the group from selfless cooperation, as it would be exploited. This is of course an oversimplified but it seems to show a fundamental flaw in group selection.
Doesn’t a pack of wolves outcompete solitary wolves in breeding and territory? Isn’t that basically what we’re talking about?
No.
The question isn’t whether or not groups can have increased survival success over individuals, but how that can be explained in terms of evolutionary mechanisms. To borrow from David Deutsch, it’s about the flow of information from one state to another. That behaviours on an individual or group level exist isn’t really an issue on either side – if it were then there would be nothing to fuss over and anyone who denied group selection would be wrong – but how it is we can understand those behaviours given the evolutionary process. It may be that group selection, properly formulated, is a good way of understanding those behaviours, but the opposition isn’t about whether or not such behaviours exist but whether or not it can work as an evolutionary mechanism.
There are some good talks linked here about the controversy:
http://whyevolutionistrue.wordpress.com/2010/05/17/how-important-is-group-selection/