Friday, October 30, 2009

Is there a Mutual Exclusivity Paradox in this picture?

As noted in Wikipedia, in evolutionary biology, group selection refers to the idea that alleles can become fixed or spread in a population because of the benefits they bestow on groups, regardless of the alleles' effect on the fitness of individuals within that group. Reference was also made to recent group selection models being seen not so much as as a fundamental mechanism but as a phenomenon emergent from standard selection.
As one can see from earlier posts here, I've had my own ideas and questions about group or multilevel selection as fully representative of evolutionary mechanisms in the sense that Darwin and others to follow have used that phrase.

Notably I have had online disagreements with Dr. D S Wilson, a noted proponent of group selection as characterizing such a mechanism - and especially with his contention that the mechanism selects for behaviors that he and like colleagues have seen as a set of separate genetic traits, while I see these "traits" more simply as heritable algorithms (think "instincts") that carry a range of strategic behavioral options.

Except that more recently Dr. Wilson has re-posted some of the items in his Huff Post series to ScienceBlogs (Evolution for Everyone), and now concedes that we may be dealing with conditional strategies instead of fixed genetic traits, but claims that his computer models will still confirm that the evolutionary process the groups contribute to remains the same as far as selection for different behavioral traits is concerned.

Which has attracted some new commentary, and one relatively anonymous poster in particular may have put the final kibosh on this whole rather silly enterprise. While we aren't told who this person is, the stuff is nevertheless in the public domain, so I'm going to quote some of the relevant comments below. (The Wilson stuff he's commenting on is the same old, same old, of course.)

So I quote:
"Dr. Wilson,
But you haven't commented on whether an organism using altruism as a conditional strategy also has the option of using selfishness as a conditional strategy, and if so, at what point does an organism use one of these strategies so exclusively that it becomes, in effect, unconditional and measurable or identifiable as that individual's dominant trait - so that for purposes of your theories, the individuals with that trait achieve dominance in a group at one level, and their progeny, who purportedly inherit that trait, will as individual trait carriers, lose that dominance at another level where the particular strategy has (according to the models) lost its effectiveness.
In other words, why is it posited that the groups are seemingly selecting for individual organisms that carry the particular trait, rather than selecting for the traits that will then come to the fore in the new alignment of individuals? So that in the latter case, we would not have so much of a change in the phenotype as more simply one of the phenotype adapting its behavior to the group culture?

Put another way, there's clearly a mutual exclusivity paradox involved when you tie the effectiveness of the trait to the individual that carries it, rather than tie the effectiveness of the individual to the choice of that trait in a particular group dynamic.
Posted October 29, 2009 1:54 PM"

(There had been no response to the above, and apparently or partly for that reason, the same person responded to another installment in the series as follows:)

"" group selection is a form of natural selection that results in adaptations at the group level, when and if it occurs."
Could you have made that any more ambiguous? Natural selection has to mean more than an individual either being selected into the group, or selecting itself to be part of that group. Isn't it rather meant to refer to some evolutionary change of some biological structure, a change that would be subject to further change, but not to a reversal of that change (such as un-joining the group, for example). Now I suppose the phrase would refer to a super-organism as well, but does this include the type where the change is reformative but not irreversible - that wouldn't really be an evolutionary move, now would it?
And since we're at bottom here concerned with human evolution, you aren't applying the natural selection label to individual adaptations within the group that are temporary or subject to their reversal, are you? Because again, with humans at least, that will not have become an evolutionary process, but a behavior modification process where situations cause anomalous developments in individuals. Although I'll grant that if these developments are then heritable, would be examples of the group as a mechanism for directed rather than random selection.
Otherwise, and again with humans in particular, if an example of evolution by natural selection, group selection would arguably involve an evolutionary process that causes phenotypical change at an exponentially faster rate than the ones we have actually been able to account for in the discoverable history of our phenotypic evolution!
So again, could you really be talking about either a short or long term behavior modification process, and if so wouldn't that be as much an evolution (using the term loosely) of culture as of the biological process you seem to be an advocate for? The more likely biological aspect of the process then being, in essence, another example of adaptation to environmental changes - interaction with groups virtually always being an element of any changes in environment?
Posted October 29, 2009 8:44 PM"

So while personally I might have said things differently, I might not have said them better, or at all. And as far as I'm concerned, any configuration that purports to effectively function as a group "selection" process is not likely to offer more than a variation of evolutionary adaptation, whether to a new environment, a new cultural milieu, or as in most cases, to some combination thereof.

Or, and in my view even more likely, it will be a facilitator of what some refer to as the Baldwin effect, which occurs, in theory, when a biological trait becomes innate as a result of first being learned. And I'm of the opinion that much of the motivation behind these experiments is to find an alternate way of explaining how such traits might have so successfully evolved without that learning.

And already some are referring to the "mutual exclusivity paradox" as if it's familiar terminology and somewhat old news. And for all I know it is.