Saturday, April 26, 2008

Reconsiderations: Richard Dawkins and His Selfish Meme

From The New York Sun, a look back at Richard Dawkins' selfish gene, and whether or not the theory still holds with what we currently know.

From what I can tell, the reality is a mixture of selfish genes and group dynamics -- and now there seems to be evidence that environment has a huge impact on evolution.

From its attention-grabbing title to its accessible prose, Richard Dawkins's "The Selfish Gene" (1976) has (selfishly) spread its message in an impressive way since publication.

Proclaimed brilliant for its portrayal of the "gene's-eye view" of evolution, Mr. Dawkins's book inverted the focus of natural selection, from Darwin's weight on species to Mr. Dawkins's emphasis on the lowly gene itself: Simply put, Mr. Dawkins's argument is that the crux of natural selection is whether a particular gene — not an individual or a group of individuals — replicates itself in future generations. Those genes that are not replicated into the future have failed at evolution, and those that produce many copies of themselves have succeeded.

In Mr. Dawkins's view, the organisms containing those genes are merely "lumbering robots" or "survival machines" that house and carry genetic information. The implication is that, in these terms, selfishness, even ruthless selfishness, pays off, and altruism does not.

Some predicted that this book would be the death knell of the idea of group selection. No longer would evolutionary biologists suggest that natural selection worked to promote the good of the species (group selection) or even the individual and his close relatives who share many of his genes (kin selection, a type of group selection).

But prediction is difficult in a contingent world such as ours, where life is complex and accidents and coincidences wield so much power. Has "The Selfish Gene" in fact killed off group selection ideas? Why not? And what effect has the book had instead?

Though selfish genes are still fashionable among evolutionary biologists, group selection and kin selection, its subset, are not dead. In 2007, David Sloan Wilson, professor at Binghampton University, and E.O. Wilson (no relation), a professor emeritus at Harvard University and a Pulitzer Prize winner, proclaimed that Mr. Dawkins had celebrated the death of group selection prematurely.

The pair asserted persuasively that altruism and cooperation can be adaptive if they are directed toward relatives who share a suite of one's genes (kin selection) or if relationships can be established within a group in which cooperation is rewarded with future reciprocity.

Further, when competition between groups is more significant than that within a group, natural selection can operate on multiple levels, from gene to kin group to species and perhaps beyond. An individual meerkat who stands watch and warns others of the presence of a predator increases its personal chance of being eaten, but its kin group — with which the watcher shares many genes — attains a higher survival rate compared to other such groups without watchers. In each example, the evolutionary disadvantage to the individual must be weighed against the evolutionary advantage to its larger group (kin, population, or even species). Since altruistic behaviors do occur, evolution must operate at both the higher (between-group) as well as the lower (within-group) level.

This multilevel view of evolution accords well with a concept espoused by the late John Maynard Smith, formerly an emeritus professor of the University of Sussex, and Eörs Szathmáry, professor at Eötvös Loránd University, Budapest. The pair suggested that evolutionary history is marked by major transitions that correspond to successively more complex levels of organization.

A favorite example of such a transition is the development of eusociality, the most extreme instance of group selection, on which Mr. Wilson is one of the world's experts. Eusocial species (termites, ants, wasps, naked mole rats, and others) live in large colonies in which many individuals forego reproduction to assist a single queen. Mr. Wilson's classic 1975 book "Sociobiology" attributed eusociality to the close genetic relationship along the colony members. But careful observations have since shown that sterile workers cannot recognize each other, much less base their behavior on fine calculations of relatedness — a finding suggesting that the broader mechanism of group selection, rather than the more direct kin selection, was responsible. Mr. Wilson now suggests that eusocial behavior evolves in rare species that have the flexibility to be reproductive or not, and that live in circumstances inhibiting the dispersal of nests. Once forced to live together rather than founding new colonies, species preadapted to cooperation successfully adopt eusociality precisely because it is evolutionarily advantageous.

A quip sometimes called Orgel's Second Rule is "Evolution is cleverer than you are," and evolution is apparently cleverer than Richard Dawkins, because kin and group selection do exist — and pay off. However, an essential aspect of being a scientist is to test your theories against new data, and the sheer provocativeness of Mr. Dawkins's selfish-gene concept spurred a great deal of hard thought and data collection that have been used to test his hypothesis. Mr. Wilson's new turn of mind is but one of several indications that the scientific understanding of evolution has shifted since the first wave of enthusiasm for "The Selfish Gene." (New data suggest that, in some circumstances, selection does operate at the group level.) The meerkat is not eusocial, but group selection works for it in some cases. Thus, Mr. Dawkins's work has been remarkably fruitful, even if his extreme stance — that natural selection works only on the single-gene level — is looking more and more shaky.

An ironic legacy of Mr. Dawkins's work also deserves exploration here. Because his works are so lucid and so stunning, Mr. Dawkins's ideas have assumed a life of their own. His powerful metaphor of the inherent selfishness of the gene was misunderstood by many and often taken deeply to heart. One reader wrote that reading "The Selfish Gene" triggered a 10-year series of depressions because "it presents an appallingly pessimistic view of human nature and makes life seem utterly pointless; yet I cannot present any argument to refute its point of view." The picture of evolution offered by the book, and others by Mr. Dawkins, which many found bleak, also contributed to the growth and stridency of the intelligent design movement to undercut the teaching of evolution in public schools.

Mr. Dawkins foresaw this possibility and attempted to avoid it by writing:

I am not advocating a morality based on evolution. I am saying how things have evolved. I am not saying how we humans morally ought to behave.... I stress this because I know I am in danger of being misunderstood by those people, all too numerous, who cannot distinguish a statement of belief in what is the case from an advocacy of what ought to be the case.

Unfortunately, his warnings against taking moral and ethical lessons from scientific findings were not universally heeded. The benefit to science of "The Selfish Gene" in triggering a new understanding of the magnificent complexity of evolutionary processes must be weighed against the harm the book has done in provoking a backlash against science. I can only hope that, in the end, knowledge will triumph over ignorance.

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