Group Selection and the Evolution of Morality

Perhaps the best single article I have read on the group selection debate is “Evolution ‘for the Good of the Group’”, in American Scientist, September-October 2008.  It is another collaboration between the two Wilsons, E. O. and D.S.  I would add that it is also a very good introduction to the general question of the levels of selection‑genes, individuals, and groups, within a population. 

Group selection is one explanation for the evolution of altruism.  Any time one organism (or any unit within an organism) behaves in such a way as to confer a reproductive advantage to another organism at its own expense, this is evolutionary altruism.  Honey bee workers who serve the queen but do not themselves reproduce are behaving altruistically.  A vampire bat who regurgitates some hard won blood to feed a hungry roost mate is another example.  Many examples of altruism are easily explained in terms of deferred gratification (reciprocity) or benefit to closely related individuals (kin selection). 

Group selection theory is based on the claim that some altruistic behaviors are selected for because they benefit the group without any return to the altruist whether direct (deferred gratification) or indirect (kin selection).  A group with more altruists will be more reproductively successful than a group with fewer and so altruists may increase in the total population, at least initially.  Increase in the total population is what we mean by evolution. 

There seems to be an insuperable problem.  While between group selection might well favor altruistically endowed groups, within group selection will favor the selfish over the public spirited organisms.  Altruists would seem to be doomed to inevitable extinction as their selfish fellows outbreed them.  In this view, which held the field for a long time, group selection is unsustainable. 

However, group selection does in fact occur.  Wilson and Wilson present a number of forceful examples.  My favorite is the bacterium Pseudomonas fluorescens.

When this species is cultured in an unstirred broth, the cells soon consume most of the oxygen in the bulk of the medium, so only a thin layer near the surface remains habitable. A spontaneous mutation called wrinkly spreader causes cells to secrete a cellulosic polymer that forms a mat and helps them colonize the water surface. Production of the polymer is metabolically expensive, which means that nonproducing “cheaters” have the highest relative fitness within the mat; they get the benefit of the mat without contributing to its upkeep. However, if the proportion of cheaters grows too high, they are undone by their own success. The mat disintegrates, and the entire group sinks into the anoxic broth. Experiments by Paul B. Rainey and Katrina Rainey have shown that the wrinkly spreader trait is maintained in the population by group selection, even though it is disadvantageous within any one group.

This example illustrates the fact that the “free rider problem” is real.  The benefits of altruism in between group selection can indeed be undone when selfish cheaters crowed out the altruists.  At the same time, the very fact that mats form at all demonstrates that group selection was a powerful force in the evolution of this microbe.  Wrinkly spreader can only be maintained by its benefit to the community. 

Obviously, what is needed to maintain group selection is some mechanism for suppressing cheating.  I have no idea how this is done by bacteria but Christopher Boehm has a good idea how it is done among human hunter gatherers.  He argues in Moral Origins that social selection (reproductive benefits that result from a reputation for altruistic behavior) and sanctions against bullies (free riders) functioned to protect altruists from cheaters. 

Human beings are extraordinarily capable of altruism toward unrelated individuals.  Explaining this is a big challenge for evolutionary theory.  Boehm considers a number of explanations that are current in the scholarship.  He doesn’t reject them, but argues that some of them work only when cheating is suppressed by the mechanisms mentioned above. 

In Plato’s Gorgias, Socrates argues that justice is analogous to medicine: it is a response to dysfunction in the social body.  I am inclined to think that the theory of group selection is beginning to uncover something like the Platonic idea of justice.  It may be that retribution is something that shapes all life on earth. 

The Animal At Odds With Itself

Aristotle wrote two fundamental books about the human being: the Nicomachean Ethics and the Politics.  I have long thought the two works are based on contrary assumptions.  The one proceeds on the assumption that the human thing is the action of an individual person.  The other proceeds on the assumption that the human thing is the action of a regime or a political community.  So which is it?  Is the human thing the individual or the group?

I think that the answer to that question emerges precisely from the fact that Aristotle found it necessary to take the two points of departure.  The human thing is the dynamic relationship between the moral person and the moral/political community.  It is in that dynamic relationship that one sees most clearly what the human being really is. 

The current issue of The New Atlantis has four pieces on “the evolution of human nature”.  I just finished two of them: “The Evolutionary Ethics of E. O. Wilson” by Whitley Kaufman and “Moderately Socially Conservative Darwinians” by Peter Augustine Lawler.  Both are well worth reading and both confirm at least this much of my view of the human thing: to say what we are is to describe a tension or even a conflict between two distinct modes of being. 

Kaufman takes issue with E. O. Wilson’s argument that

our best chance at understanding and advancing morality will come when we “explain the origin of religion and morality as special events in the evolutionary history of humanity driven by natural selection.

Kaufman presents the weakness of Wilson’s biophilia.  This is the idea that we should love the earth and all the beings who live on it.  I think that this is not a bad idea at all.  Gratitude might be the better part of piety.  I agree, however, that Wilson has not done the hard work necessary to turn biophilia into a coherent ethical position. 

The problem is that Wilson seeks to bring about a revolution in ethics without doing ethics — that is, without making any prescriptions, only predictions. He has painted himself into a corner: biophilia in his theory can only be a personal preference, not an objective value.

What interests me here is the tension that Kaufman identifies in Wilson’s work.  On the one hand, Wilson

celebrates the infinite capacities of man to increase knowledge, breathlessly predicting that “humanity will be positioned godlike to take control of its own ultimate fate.” In On Human Nature, he holds that our biological tendency for aggression and war will be “brought increasingly under the control of rational thought.”

That makes it sound like we are more or less in control of ourselves and capable of taking some measure of control over human nature and nature in general.  On the other hand

Wilson’s reductionist commitments lead him to insist that free will is only an illusion. Though “some philosophers still argue [it] sets us apart” — and one would have to include Wilson among these philosophers! —nonetheless free will is no more than a “product of the subconscious decision-making center of the brain that gives the cerebral cortex the illusion of independent action.” So Wilson is at once a moralist… and a moral determinist, holding that moral decisions are causal and impulse-driven rather than rational and free. He cannot resist trying to have it both ways: we are free and determined; rational and instinctual; autonomous and mechanistic…

Not surprisingly, Wilson is unable to reconcile these contradictory conceptions of free will and human nature, the humanistic and the scientific. But it is, in a way, a tribute to his breadth of mind that he recognizes and embraces both of them, in contrast to the prevailing trend in evolutionary ethics towards simple moral determinism and nihilism.

That seems to me to be right.  The human being is at once a physical being, composed of organs, cells, and molecules that obey physical laws, and a moral being capable of freedom.  No one has yet escaped from the problem that presents. 

Peter Lawler focuses on a tension that is closer to the one I pointed out in Aristotle.  On the one hand there is the position that seems to originate with Descartes. 

Sophisticated Americans these days think of themselves, or at least talk about themselves, as autonomous beings — free from old-fashioned social restraints, and free even from the limitations of nature. Men and women both feel free to define who they are for themselves, without being saddled by the imperatives of their biology, their bodies.

That is the position of radical individual autonomy, divorced from nature in general and biology in particular. 

Lawler presents a sympathetic account of the Darwinian alternative, as argued by Larry Arnhart, Jonathan Haidt, and E. O. Wilson.  Human beings are animals.  We are conditioned by our biological nature to be selfish but also to seek to belong to larger groups. 

Darwinians think of our cultural evolution as an extension of our natural evolution, and they see both as having an equally social and biological foundation.

Wilson sees members of our species as much more like bees and ants — the insects that he studied during his distinguished career as an entomologist — than even our fellow primates. These insects achieve their unrivaled social cooperation, which includes a complex division of labor and shared responsibility for taking care of the young, through robotically perfect obedience to social instinct; these instinctual traits define what Wilson and other entomologists have termed “eusociality.” We human beings much more consciously employ our intellects in the service of social instinct to reach our own heights of cooperation. The social intelligence of human beings — the self-aware animals with complex speech — leads to a tension between the selfish desires created by individual-level selection and the social impulses created by group-level selection, a tension that hardly exists for the instinctively self-sacrificial eusocial insects.

Lawler is wrong to say that the tension between individual interest and collective interest “hardly exists” for the eusocial insects.  In fact it is pervasive and must be managed in a variety of ways.  Honey bee workers can lay their own eggs and will tend them, unless the queen polices the system by eating them. 

The Darwinians, I am surely among them, think that human beings are by nature political animals, as did Aristotle. 

It is true that we are selfish and struggling by nature. But, as [Haidt] argues in The Happiness Hypothesis, we are also “hive creatures who long to lose ourselves in something larger.” The only thing that gives us a sense of purpose worth dying for — that saves us from what would otherwise be our lonely and self-destructive personal obsessions — is the group, or our relations with members of the group. We cannot live well without knowing that there is something that makes self-sacrifice significant. We are unable to achieve what the bees and ants have — complete instinctual self-surrender. But our happiness is still fundamentally about having the “right relationships.”

Again, this seems to me to be right.  The individual human being presents itself as both autonomous and part of a larger whole.  We are selfish and selflessly committed to others.  We are persistently at odds with ourselves and that is what we are. 

I highly recommend Lawler’s essay.  He believes, I think, that human beings are more than animals.  He takes the possibility of the immortality of the human soul more seriously that I do or than Aristotle did.  I would only add that human beings are at least animals.  Our animal nature contains the fundamental tension that drives so much of moral and political philosophy. 

Politically Correct Darwin

At least since the publication of Edward O. Wilson’s Sociobiology, the American left has had an ambivalent reaction to Darwinian biology.  The left likes Darwinism in so far and because religious conservatives don’t like it.  When it is a question of the Bible vs. The Origin of the Species, the left thinks that anyone who questions Darwinism is a retrograde fool.  The left hates Darwinism when it is applied to human social and political behavior, for they think that any conception of human nature is a threat to the promise of social reform. 

These days the issues are rather more complicated than they were when Wilson was denounced in The New York Review of Books.  The ambivalence remains, however.  The New York Times recently published a defense of homosexuality from a biological point of view by David George Haskell.  Here is a taste:

The facts of biology plainly falsify the oft-repeated notion that homosexuality is unnatural. Every species has evolved its own sexual ecology, and so nature resists generalizations. Does humanity’s natural inheritance include homosexual bonds and behaviors? Certainly. This conclusion is reinforced by the growing evidence that our sexual orientation is influenced by both our genes and the environment that we experience in the womb.

This strikes me as plausible but very provisional.  We hardly have a good understanding of the natural causes underlying homosexual orientation.  It is far from clear whether homosexual behavior is in some way biologically functional, let alone whether gay marriage is a good idea.  Haskell’s piece doesn’t bother with the ambiguities. 

On the other hand, the Times doesn’t much like evolutionary psychology.  If the latter tells us anything, it is that male and female sexual behavior and instincts are robustly dimorphic.  What it tells us is wrong, according to journalist Dan Slater.  In “Darwin was wrong about Dating,” he explains that:

Lately a new cohort of scientists have been challenging the very existence of the gender differences in sexual behavior that Darwinians have spent the past 40 years trying to explain and justify on evolutionary grounds.

Wow.  Maybe all those gender differences that evolutionary psychology has painstakingly documented don’t really exist.  Slater offers us a small selection of studies that seem to deny gender differences.  Voilà! 

The only problem with this is that it flies in the face of the most obvious facts.  Consider pornography, for example.  Walk into an adult bookstore (purely for research purposes, of course) and ask yourself: to whom is all this stuff being marketed?  I predict (having done my own research) that virtually all of it is marketed to heterosexual or homosexual males.  Unless someone can show me that I am wrong (I am intrigued by the possibility), I submit this as a very robust fact. 

Consider also prostitution.  Allow me to suggest that virtually all prostitutes, both male and female, service males exclusively.  That men frequently pay for sex while woman almost never do strikes me as another robust fact.  There are solid Darwinian explanations for why these differences are so pronounced and so universal.  These explanations ground human behavior in the general biology of animals.  Across a very wide range of organisms, males produce more offspring when they obtain access to more mates.  Females do not. 

The New York Times likes Darwin when he is politically correct.  When he is not, they usher in someone to usher him off the stage.  It is a quixotic charge.  As long as science is allowed to progress, nature, as Anthony Hopkins says in The Wolfman, will out.  If the Church could not prevail against Darwin, neither will the church of The New York Times. 

The Two Wilsons on Group Selection

In connection with the paper I have been writing, I have been thinking a lot about group selection.  I have incorporated this quote from E. O. Wilson’s The Social Conquest of the Earth:

An iron rule exists in genetic social evolution.  It is that selfish individuals beat altruistic individuals, while groups of altruists beat groups of selfish individuals.  The victory can never be complete; the balance of selection pressure cannot move to either extreme

This strikes me as a very powerful formulation.  It includes the fundamental problem presented by the evolution of morality.  Here is how David Sloan Wilson and Edward O. Wilson put it in RETHINKING THE THEORETICAL FOUNDATION OF SOCIOBIOLOGY (Quarterly Review of Biology, December 2007).  

During evolution by natural selection, a heritable trait that increases the fitness of others in a group (or the group at a whole) at the expense of the individual possessing the trait will decline in frequency within the group. This is the fundamental problem that Darwin identified for traits associated with human morality, and it applies with equal force to group-advantageous traits in other species. It is simply a fact of social life that individuals must do things for each other to function successfully as a group, and that these actions usually do not maximize their relative fitness within the group.

The question here is how to explain the emergence of genuinely altruistic behaviors in human beings and other animals.  What separates the Mensheviks from the Bolsheviks in contemporary evolutionary theory is that the former try to explain it away whereas the latter try to explain how it can be what it seems to be. 

Explaining it away means interpreting apparently altruistic behavior as selfish behavior, keeping the rule that any behavior selected for must advance the genetic interests of the individual within the group.  If I share my kill with the rest of the tribe, that is because big hunters get lots of pussy. 

Explaining altruistic behavior while accepting that it is, genuinely, altruistic, may require group selection.  Cooperation is a trait not of individuals but of partnerships.  If you and I make sacrifices for each other, our business model turns a profit.  Groups with a lot of altruists out compete those with few, resulting in an increase of altruists in the larger population. 

I suppose that both approaches have value, but that puts me squarely on the side of the Bolsheviks.  The Mensheviks will allow only the selfish interpretation. 

The other thing that is presented in the E. O. Wilson quote is that group selection best makes sense of the moral dimension in human beings.  If group selection works, it will work against directly selfish behavior and the resulting schema will produce a being at odds with himself.  That would be me and you and all of us human beings. 

I also note that E. O. Wilson’s quote contains the paradox that we find in the prisoner’s dilemma.  In that diabolical issue of game theory, it makes perfect sense for each of us to defect in our partnership; nonetheless, we would both be better off if we cooperated.  I think that the Wilson’s are on to something.