I appreciate the effort you are putting into this, but I fear the terminological and theoretical confusion regarding group selection run far too deep. One enthusiastic person is not going to straighten things out in a forum where evolutionary biology is not the central focus. And now that academian has weighed in, the cause is hopeless. ;)
I agree with you (and Tim) that Eliezer’s opposition to group selection was a bit naive and under-informed. But not completely wrong-headed. Many incorrect arguments in favor of group selection have been made over the years. A lot of them were incorrect because they simply did not work. Others were “epistemologically incorrect” because, though they worked, they could be reinterpreted more “parsimoniously” as individual-level selection.
D.S. Wilson’s “Truth and Reconciliation” blog series strikes me as an example of extremely dishonest labeling. What he is really saying is that if everyone who disagrees with him would just accept his version of the truth, then reconciliation will take place. And his book “Unto Others” strikes me as even more dishonest. He defines “group selection” extremely broadly, provides examples of corner cases in which his “trait group selection” mechanism works, and then (here is the dishonest part) claims that if group selection works even in this extreme case, then it will obviously work in other cases.
Then he proceeds to discuss the case which every non-professional has in mind when he thinks of group selection—human evolution with groups = tribes, group death = tribe extinction, and group birth = split-up of a successful and populous tribe. The trouble is that the math of group selection really doesn’t work in this case.
The only cases I know of where the group selection models do work are (1) Species level selection (Gould/Eldredge), examples like your non-selfing plants; and (2) the examples that Wilson gives in which “groups” are rather short-lived entities which “succeed” by keeping their members alive for a while and then returning them safely to the general population, where the individuals reproduce. A good example of a group that Wilson might use as an example of trait-group selection would be a flock of geese conducting a seasonal migration. Such a group might be selected against if it got seriously lost, or blundered into a tornado, or suffered some other collective catastrophe.
A human hunting party is another example of a “group” such that the mathematics of group selection works. A human tribe of hunter-gatherers is not, unless it is so reproductively isolated from other tribes so as to qualify as a species. I’m pretty sure that this degree of isolation (less than two cross-tribe matings per generation) has never held over any long period of time in human history.
But group selection for cultural traits is another question. If genes get transferred between tribes, but memes do not, then selection at the level of tribes may well help to determine the course of human cultural/memetic evolution.
Well, I seem to have provided you with a long response, which, unlike your own efforts, does not include any links/citations. Sorry about that. You are under no obligation to trust or believe me on this stuff. I will merely assert that I (and tim_tyler as well) have been a serious amateur enthusiast for evolutionary theory for many years. Clearly, you have been too. I do recommend though, that you take a second look at D.S. Wilson’s work in light of my criticisms. He really is pulling something of a bait-and-switch. See if you agree.
It sounds as though I like multi-level selection a bit more than you do.
Evidence from our own species suggests habitat variation can cause significant morphological differences (despite gene flow) which selection can then act upon.
I also find things like this one interesting:
“Senescence as an adaptation to limit the spread of disease”
It sounds as though I like multi-level selection a bit more than you do.
I think so. I’m not quite so purist as Dawkins, but I am pretty close. But I do realize that it is not really an empirical scientific question. It is really simply a matter of what kind of models you prefer. Most cases in which group selection models work can also be explained just as well by individual-level selection or kin-selection.
Speaking of which:
I also find things like this one interesting:
“Senescence as an adaptation to limit the spread of disease”
Yes. Very interesting. Red Queen strikes again. But since they are already thinking about Bill Hamilton, why don’t they take the further step and realize that the senescent death of an old individual not only reduces the population density for the benefit of the group—the death specifically is beneficial to those individuals in the group who are the most immunologically similar to the deceased.
In other words, this mechanism ain’t Red Queen + Group Selection; it is Red Queen + Kin Selection.
Their model exhibits locality (with limited diffusion—V.N. or 5x5 neighbourhood) as well.
So: a death benefits kin not just through immunological similarity—but also because neighbours are likely to be kin—and death takes an adjacent pathogen load out of circulation.
I appreciate the effort you are putting into this, but I fear the terminological and theoretical confusion regarding group selection run far too deep. One enthusiastic person is not going to straighten things out in a forum where evolutionary biology is not the central focus. And now that academian has weighed in, the cause is hopeless. ;)
I agree with you (and Tim) that Eliezer’s opposition to group selection was a bit naive and under-informed. But not completely wrong-headed. Many incorrect arguments in favor of group selection have been made over the years. A lot of them were incorrect because they simply did not work. Others were “epistemologically incorrect” because, though they worked, they could be reinterpreted more “parsimoniously” as individual-level selection.
D.S. Wilson’s “Truth and Reconciliation” blog series strikes me as an example of extremely dishonest labeling. What he is really saying is that if everyone who disagrees with him would just accept his version of the truth, then reconciliation will take place. And his book “Unto Others” strikes me as even more dishonest. He defines “group selection” extremely broadly, provides examples of corner cases in which his “trait group selection” mechanism works, and then (here is the dishonest part) claims that if group selection works even in this extreme case, then it will obviously work in other cases.
Then he proceeds to discuss the case which every non-professional has in mind when he thinks of group selection—human evolution with groups = tribes, group death = tribe extinction, and group birth = split-up of a successful and populous tribe. The trouble is that the math of group selection really doesn’t work in this case.
The only cases I know of where the group selection models do work are (1) Species level selection (Gould/Eldredge), examples like your non-selfing plants; and (2) the examples that Wilson gives in which “groups” are rather short-lived entities which “succeed” by keeping their members alive for a while and then returning them safely to the general population, where the individuals reproduce. A good example of a group that Wilson might use as an example of trait-group selection would be a flock of geese conducting a seasonal migration. Such a group might be selected against if it got seriously lost, or blundered into a tornado, or suffered some other collective catastrophe.
A human hunting party is another example of a “group” such that the mathematics of group selection works. A human tribe of hunter-gatherers is not, unless it is so reproductively isolated from other tribes so as to qualify as a species. I’m pretty sure that this degree of isolation (less than two cross-tribe matings per generation) has never held over any long period of time in human history.
But group selection for cultural traits is another question. If genes get transferred between tribes, but memes do not, then selection at the level of tribes may well help to determine the course of human cultural/memetic evolution.
Well, I seem to have provided you with a long response, which, unlike your own efforts, does not include any links/citations. Sorry about that. You are under no obligation to trust or believe me on this stuff. I will merely assert that I (and tim_tyler as well) have been a serious amateur enthusiast for evolutionary theory for many years. Clearly, you have been too. I do recommend though, that you take a second look at D.S. Wilson’s work in light of my criticisms. He really is pulling something of a bait-and-switch. See if you agree.
Thanks for your 2p on D.S. Wilson’s Unto Others.
It sounds as though I like multi-level selection a bit more than you do.
Evidence from our own species suggests habitat variation can cause significant morphological differences (despite gene flow) which selection can then act upon.
I also find things like this one interesting:
“Senescence as an adaptation to limit the spread of disease”
Josh Mitteldorf , John Pepper
http://www.mathforum.org/~josh/Epidemics-JTB.pdf
I think so. I’m not quite so purist as Dawkins, but I am pretty close. But I do realize that it is not really an empirical scientific question. It is really simply a matter of what kind of models you prefer. Most cases in which group selection models work can also be explained just as well by individual-level selection or kin-selection.
Speaking of which:
Yes. Very interesting. Red Queen strikes again. But since they are already thinking about Bill Hamilton, why don’t they take the further step and realize that the senescent death of an old individual not only reduces the population density for the benefit of the group—the death specifically is beneficial to those individuals in the group who are the most immunologically similar to the deceased.
In other words, this mechanism ain’t Red Queen + Group Selection; it is Red Queen + Kin Selection.
Yes: sex and death!
Their model exhibits locality (with limited diffusion—V.N. or 5x5 neighbourhood) as well.
So: a death benefits kin not just through immunological similarity—but also because neighbours are likely to be kin—and death takes an adjacent pathogen load out of circulation.