Evolution for Everyone

One memorable Christmas morning, as our kids were gathering around the tree, I was on my way upstairs to get a sweater when I smelled something really bad. I knew that smell. Our cat had diarrhea and had deposited a wet one somewhere. I walked all over the house trying to find it before realizing that I had stepped in it the moment that I smelled it and now had tracked it all over the house.

Did I clean it up? Of course I did. Anyone would.

Here’s another example of a mess: Imagine a man who has made a mess of his life. He has taken advantage of those who loved him and piled lies upon lies until he can’t keep them straight anymore. Now he has been abandoned and has only himself to blame. If only he could go back to the beginning!

Should this man clean up his mess? Of course he should, and would be much better off if he did, but we wouldn’t be surprised if he didn’t. It would require great courage. Twelve-step programs are designed for people like him and include acknowledging one’s faults and apologizing to others.

Here’s a third example of a mess: Imagine that an entire scientific community has made a decision that turns out to be a mistake. The decision was momentous. It was regarded as a watershed event for the field. Its architects were celebrated as heroes. It was enshrined in textbooks. Nevertheless, subsequent events had proven it to be incorrect. If the current information was known back then, a different decision would have been made and the entire field would have taken a different path.

Should the field clean up its mess? It should, but the likelihood that it will is even less than for the individual who messed up his life. After all, “the field” is not even a corporate unit capable of making a decision like an individual. Instead of a collective decision, a cacophony of responses can be expected, including acceptance, denial, and halfway positions that attempt to acknowledge change while still clinging to the patriotic history.

That is what has happened with the group selection controversy. The categorical rejection of group selection in the 1960’s was wrong, plain and simple. If they knew then what we know now, it would never have happened. Some evolutionists are perfectly comfortable with this conclusion. Others act as if nothing has changed since the 1960’s. Others say that the original rejection of group selection remains valid and what passes for group selection today is different. Others claim that group selection and its alternatives are equivalent, making it a matter of preference which to employ. Others construct models and perform experiments that anyone would have identified as group selection in the 1960’s, but just don’t use the G-word. In short, the field as a whole is a big mess.

To see what I mean, consider a four-page news feature on group selection that appeared in the November 20, 2008 issue of Nature magazine. The author is a science writer named Marek Kohn who did a thorough job researching the subject. The article begins this way:

If biologists have learned one thing about evolution over the past 40 years, it is that natural selection does not work for the good of the group. The defining insight of modern Darwinism is that selection ‘sees’ individuals and acts on them through the genes they embody. To imagine otherwise, generations of students have been warned, is to fall into a naïve error definitively exposed as such in the 1960’s.

So far so good. But then we learn that the two sides actually agree on a great deal. For example, everyone today supposedly agrees that group selection occurs and that group selection and kin selection are formally equivalent to each other. Evidently, the debate about group selection is largely semantic and choosing between one and the other is a matter of preference.

I will untangle some of these issues in future posts. The point I wish to make here is that the positions reported in the Nature article bear almost no resemblance to the issues at stake in the 1960’s. Back then, the center of the debate was what I have called “The Original Problem (see T&R II)”, almost everyone agreed that group selection did not occur (although they agreed it was possible in principle), and kin selection was regarded as a theory that succeeded where group selection had failed. Does anyone seriously think that the “defining insight of modern Darwinism” was merely semantic? Somehow, the issues at stake in the 1960’s have been permuted into a different set of issues, while everyone pretends that it is the same controversy. I do not fault the author of the article. As a science writer, the best that Kohn could do was report the views of the experts. The problem is that he had to report a mess.

As for everyone today agreeing that group selection occurs, I wish that someone would tell John Alcock, author of Animal Behavior, the most widely used textbook in the field. Alcock truly believes that nothing has changed since the 1960’s. So great is his loathing of group selection that he calls it “non-Darwinian”–an irony, since Darwin clearly originated the concept (see T&R II). Regardless of what the Master thought, Alcock can’t even bring himself to say that group selection is a form of natural selection that results in adaptations at the group level, when and if it occurs. Legions of college students have been taught by Alcock that “the overwhelming majority of scientists studying the evolution of animal behavior employ Darwinian theory, rather than group selection theory in any of its forms (7th edition, published in 2001).”

Or how about my colleague, Dr. X, who has been harassed throughout his career for writing about subject Y from a group selection perspective? For example, colleagues refused to publish articles with him unless he removed all references to group selection. Dr. X is a real person but–I’m not kidding–he does not want his identity revealed to avoid further harassment. He recently sent me the following message about a newly published article on subject Y:

It just gives you an idea of what people like me are always up against. The argument in this paper is completely group selectionist but neither the term nor the concept is invoked. Instead, the buzz terms become “coalition building”, the formation of “alliances”, etc. etc. It’s fashionable among the cooperation bunch to talk about coalitions and alliances, but they never come to grips with the levels-of-selection issue… So, things are just as they have been all along.

The problem of packaging old wine in new bottles–ideas that anyone would have associated with group selection in the 1960’s, but without using the G-word–pervades the modern literature, as I will show in future posts.

I don’t want to overstate the degree of censorship and persecution that people have suffered by daring to invoke group selection. My career has not suffered, for example, and believe it or not I count George C. Williams as a good friend. Moreover, the biggest tragedy is not injustices to individuals but the fog of confusion that descends over an entire field when major mistakes are not acknowledged.

At the end of T&R II, I stressed that there is an underlying simplicity to the group selection controversy. The only way to recover the simplicity is by cleaning up the mess that was made by falsely rejecting group selection in the 1960’s. That is my next task, but I warn you: It smells really bad.

To be continued.

Comments

  1. #1 Rosie Redfield
    October 29, 2009

    As with most of science, little is gained by “possible vs impossible” arguments.

    What we’ve learned is that group selection is possible, but only under much more restrictive conditions than individual selection. So before we invoke group selection to explain a phenomenon we need to make sure that it can’t be explained by individual selection.

  2. #2 abb3w
    October 29, 2009

    DSW: Evidently, the debate about group selection is largely semantic and choosing between one and the other is a matter of preference.

    The solution would appear being increase in the amount of formal mathematics used in description. Words are far more ambiguous than numbers.

    The reason I inquired previously about the definition of a “group” is that what appears to be an “individual” at the (eukaryotic) organism level is a “group” at the cellular level. Biologists therefore already appear to all support “group” selection implicitly.

  3. #3 InfuriatedSciTeacher
    October 29, 2009

    Perhaps it’s more a matter of consciousness raising with the newer generation of biologists and waiting for some of the “group selection is completely invalid” crowd to retire? There’s currently a similar situation in Science Ed., where empirical research has fallen out of favour with many people who adopt a relativist, case-study only research philosophy… The rest of us have to wait until those people aren’t used as reviewers for every publication on certain topics to get anything through, since contradicting them, with evidence or without, is a guaranteed death knell for your publication.

  4. #4 daedalus2u
    October 29, 2009

    I am a newbie to the group/individual selection wars, and don’t know all the jargon or arguments yet.

    Naively, in vertebrates, there can be no “individual” selection because it takes a group to reproduce (a group of two). Successful reproduction is only a consequence of this group activity and the result is transmission of a subset of the genome of the group (not the genome of an individual).

    To the extent that an individual is successful at reproducing, so is the group of two that the individual is reproducing in.

  5. #5 InfuriatedSciTeacher
    October 29, 2009

    Daedalus>

    Successful reproduction is only a consequence of this group activity and the result is transmission of a subset of the genome of the group (not the genome of an individual).

    Well, firstly, the individual view would state that the individual genes are what is being transmitted, not the genome of the individual. It’s a lottery for each offspring as to which half of the parents’ genomes are transmitted, but both halves are used for many vertebrate reproductions (most produce multiple offspring per attempt, some fish and amphibians are basically broadcast spawners, having tens or hundreds of young at a time. Some mammals take the K-strategy further than others, investing all their time and energy into one offspring at a time instead of a litter of six, of whom only some will survive; These (and K-strategists in general, to my knowledge, are the exception, not the rule amongst sexually reproducing species) The selection itself is the ability to get to reproduce, either through survival pressures or sexual selection for mating rights. Each individual faces those pressures as an individual in the instance you describe.

  6. #6 InfuriatedSciTeacher
    October 29, 2009

    Since someone who knows better may jump on this, I’m referring to r/K strategies in terms of reproduction, not life histories. I’m aware that the distinctions blend more if you include longevity and body size.

  7. #7 Guy
    October 29, 2009

    Hi Rosie,

    I have great respect for your work, but I strongly disagree with the priority argument you are making. I do not think a convincing case has been made that the conditions allowing group selection are more restrictive than those allowing individual selection, although current differences in material constraints may make individual selection predominant in most systems today (an empirical question). An argument for priority could be made in a different way, although I am not generally a fan of explanatory priority in science. Multilevel selection requires fewer assumptions (more relaxed conditions) than any model of selection at a single level, so we should make sure that selection at other levels is not involved before attributing evolutionary effects to individual selection alone. In general, I see arguments for explanatory priority as ways to avoid difficult questions. They are like relying on parsimony (I’m not referring to phylogenetic methods here); in the absence of contradictory evidence or logic, we should favor a particular explanation. That is a pretty weak basis for drawing conclusions. It would be better to seek evidence or develop critical logical arguments (e.g., good models).

  8. #8 piker
    October 29, 2009

    ” 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?

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