By the 1960s, evolutionary theory had settled into a comfortable paradigm called the Modern Synthesis. With other major issues apparently settled (go here for an update on the Modern Synthesis), the issue of group selection began to occupy center stage. George C. Williams was not the only critic and the great AEPPS were not their only foil (see T&RIII). Across the Atlantic, the Scottish biologist Vero C. Wynne-Edwards published an ambitious volume titled Animal Dispersion in Relation to Social Behavior (1962), which claimed that animal populations evolve to avoid overexploiting their resources. Wynne-Edwards was aware that such restraint was “for the good of the group” and might be vulnerable to less prudent behaviors within the group. Nevertheless, he thought that between-group selection easily trumped within-group selection and proceeded to interpret a vast array of social behaviors as adaptations to regulate population size. His book stimulated widespread debate and skepticism from prominent evolutionists such as David Lack and John Maynard Smith.

Another major event in the 1960s was William D. Hamilton’s inclusive fitness theory, more widely known as kin selection theory, a term coined by Maynard Smith. Hamilton reasoned that a gene for altruism could evolve if it favored copies of itself in the bodies of other individuals. An identical twin is certain to have the same genes as oneself, a full sibling has a 50% probability, and so on. For an altruistic gene to have a net benefit, the cost to the altruist must be outweighed by the benefit to the recipient multiplied by the probability of sharing the same gene identical by descent. Here was a way to explain the evolution of altruism — among genealogical relatives, at least — without invoking group selection. Indeed, Maynard Smith coined the term “kin selection” to distinguish it from group selection in an article criticizing Wynne-Edwards.

Hamilton’s theory had a remarkable corollary. Ants, bees, and wasps (but not termites) have a peculiar genetic system called haplo-diploidy, in which females are produced sexually and have two sets of genes but males are produced asexually and have one set of genes. A consequence of haplo-diploidy is that, when a female mates with a single male, her daughters have a 75% chance of sharing the same genes (because they all get the same genes from their father) rather than a 50% chance for diploid species. Thus, not only did Hamilton’s theory explain the general phenomenon of altruism among genealogical relatives, but in the same stroke, it seemed to explain the extreme altruism exhibited by ants, bees, and wasps on the basis of their extreme degree of relatedness (termites remained an unexplained exception to this rule).

When Williams published his book Adaptation and Natural Selection in 1966, it seemed to provide a synthesis for the subject of group selection, settling the issue in the same way that the modern synthesis settled other major issues in evolutionary theory. Williams attacked naïve group selectionism and forcefully asserted what Darwin, Fisher, Haldane, and Wright already knew: Higher-level adaptations require a process of higher-level selection and tend to be undermined by selection at lower levels. Here is one of his canonical statements (p. 92-93):

It is universally conceded by those who have seriously concerned themselves with this problem that…group-related adaptations must be attributed to the natural selection of alternative groups of individuals and that the natural selection of alternative alleles within populations will be opposed to this development. I am in entire agreement with the reasoning behind this conclusion. Only by a theory of between-group selection could we achieve a scientific explanation of group-related adaptations.

Notice that Williams is affirming the basic logic of group selection theory, but then he went further in a continuation of the same passage:

However, I would question one of the premises on which the reasoning is based. Chapters 5 to 8 will be primarily a defense of the thesis that group-related adaptations do not, in fact, exist. A group in this discussion should be understood to mean something other than a family and to be composed of individuals that need not be closely related.

In other words, even though group-level adaptations can evolve in principle, Williams claimed that in reality between-group selection is almost invariably trumped by within-group selection. This empirical claim became known as the theory of individual selection. The final sentence about families left the door open for kin selection, a point to which we will return.

Adaptation and Natural Selection was widely praised as a resolution to the group selection controversy. For the rest of the 20th century, group selection was taught primarily as a way not to think about evolution. “For the good of the group” thinking was regarded as just plain wrong. Everything that evolved by natural selection was interpreted as a variety of self-interest.

Read the entire “Truth and Reconciliation for Group Selection” Series:

00. Prologue for the Twelfth Anniversary Edition

01. Why It Is Needed 

02. The Original Problem

03. Naïve Group Selectionism

04. The Great Reckoning 

05. The Patriotic History of Individual Selection Theory

06. Individualism

07. If You Make A Mess, Should You Clean It Up?

Published On: March 9, 2022

David Sloan Wilson

David Sloan Wilson

David Sloan Wilson is president of Prosocial World and SUNY Distinguished Professor Emeritus of Biology and Anthropology at Binghamton University. He applies evolutionary theory to all aspects of humanity in addition to the rest of life, through Prosocial World and in his own research and writing.  A complete archive of his work is available at www.David SloanWilson.world. His most recent books include his first novel, Atlas Hugged: The Autobiography of John Galt III, and a memoir, A Life Informed by Evolution.


  • Steve Davis says:

    David, you wrote; “Thus, not only did Hamilton’s theory explain the general phenomenon of altruism among genealogical relatives, but in the same stroke, it seemed to explain the extreme altruism exhibited by ants, bees, and wasps on the basis of their extreme degree of relatedness…”

    The precise nature of the definitions of biological fitness and biological altruism create a serious problem for Hamilton’s hypothesis. The concept claims to explain the origin of altruism, to which you seem to agree, but when altruism is an act that lowers fitness and fitness is the capacity to produce adult offspring, we see that altruism within kinship groups is becoming difficult to explain. It simply cannot be argued that raising offspring is altruistic. Can a mother feeding a child be seen as altruistic? Feeding a child is a demonstration of fitness and therefore cannot lower fitness. Raising a child cannot be seen as reducing the capacity to raise a child. Parental altruism is therefore impossible.
    The same problem exists for kin altruism. Assisting the survival of cousins is an inclusive fitness act, a demonstration of inclusive fitness, and therefore cannot lower inclusive fitness. Assisting the survival of cousins cannot be seen as reducing the capacity to assist their survival, so kin altruism is a fiction. Kin altruism also fails as it is a function carried out at the group level and there is no nett loss of group fitness.

    Does assisting cousins lower the individual fitness of the actor? Yes, but only in a sense so narrow as to be meaningless. Consider Hamilton’s position that the concept of inclusive fitness is “stripped of all components which can be considered as due to the individual’s social environment”. If we accept the stripping of all social components then it must be acknowledged that we are now dealing with a concept that is separated from reality. In reality, assistance to kin is reciprocated; the loss of individual fitness is regained, so there is no nett loss of fitness for the individual therefore there is no altruism.
    There is therefore no such thing as kin altruism or reciprocal altruism, as there is no loss of fitness involved in both cases. Kin selection is no more than a construct comprised of a jumble of contradictory meaningless concepts, and it certainly does not explain the origin of altruism.

    In the case of the ants bees and wasps you mentioned, when a worker bee or ant feeds the queen, or feeds pupae, she cannot lower her direct fitness as she has no direct fitness. She is sterile, therefore has no fitness, therefore cannot lower fitness, therefore cannot be altruistic. Can a sterile female have indirect fitness? Let’s assume she can. Her act of feeding the queen or pupae contributes to the production of adult offspring of the queen. Because feeding the queen or pupae is (we are assuming) an indirect fitness act, a contribution to the fitness of kin, it is a demonstration of fitness not a lowering of fitness. Contributing to the fitness of kin cannot be seen as reducing the capacity to contribute to their fitness. As such it cannot be seen as lowering fitness, therefore such acts are not altruistic.

    In regard to the extreme degree of relatedness you mentioned as creating high level cooperation in the case of the eusocial insects, E O Wilson wrote years ago that organisms (in general) do not live together because they are related, they are related because they live together. To my mind that is the essence of this whole debate. Shared genes are not essential for cooperation in the natural world. One thing only is essential for cooperation; shared space. Proximity, in other words.

    Hamilton’s position is untenable. An explanation of social evolution that is stripped of social environment components !!??? He was pushing an ideological barrow.

  • Steve Davis says:

    I cannot resist giving the opinion of Prof. Lyn Margulis on all this.
    We owe a huge debt to Margulis, not only for her incredible insight into the origin of the eucaryotic cell, putting her among the greats of biology, but also for the following. Margulis has described neo-Darwinism as; “a minor twentieth century religious sect within the sprawling religious persuasion of Anglo-Saxon Biology” and believes that her (Hamiltonian) opponents “wallow in their zoological, capitalistic, competitive, cost-benefit interpretation of Darwin—having mistaken him.”  
    Her reference to “Anglo-Saxon” biology as a religion is, I think, misplaced. I believe the problem she refers to should be labeled “Anglo-Norman ideology” because it was only after the Norman invasion of England that the peculiarly British cultural oddity we now know as individualism, emerged as a significant social force. The concept was eventually given written form and “philosophical” credibility by Thomas Hobbes and John Locke, after which it never looked back.

    So powerful was its grip on the imagination of a sector of the British intelligentsia that Darwin’s most prominent supporter, Thomas Huxley, was unable to accept Darwin’s description of social instincts as superior to individual instincts, and more significant than individual instincts as a factor in evolution. Huxley salved his conscience by hiding the importance of sociality in a mere footnote to his lengthy essay Evolution and Ethics (1894), a concealment that must rank as one of the more notable abandonments of ethics in the history of science. This was not a misunderstanding of Darwin, it was in fact a deliberate distortion of Darwin’s teaching.

    That concealment of the importance of sociality in evolution continued and came to fruition with Hamilton’s inclusive fitness claims, and all the subsequent nonsense about selfish genes.
    Hamilton’s blatant contempt for the principles of the scientific method was evident from his very first paper, a contempt that influenced all his earlier works, (Geometry For The Selfish Herd is typical) works that set him up as an authority.

    Hamiltonians, (incl. Dawkins who claimed that parasitism is universal) have a strange obsession with cheating and parasitism, and no wonder. The cult of individualism that they serve so well is itself parasitic. A psycho-analyst could have a field day with that!

    But we must give the Hamiltonians credit where it is due. By focusing on a biologically insignificant definition of altruism, they successfully diverted attention from the most important factor in social evolution and evolution in general – cooperation. Why? Because as in the fable of the frog and the scorpion; that’s what scorpions do.

    So here’s the thing. The important work being done by The Evolution Institute is continually undermined by Hamiltonian thought.

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