will leave fewer progeny and his genes for altruistic behavior will soon be eliminated from the population. How therefore could altruism or other forms of self-denying, pro-social behavior ever have evolved or be maintained?
The answer that occurred to Darwin was that natural selection could take place at the level of a group of people, not just at the individual level. A society full of altruists, say of men ready to sacrifice their lives in battle, would be very likely to prevail over a less well-motivated group. Just as some individuals within a group will be more successful than others and leave more progeny, so it is in the struggle between groups. The more unified societies, those whose members contain a larger proportion of pro-social genes than do their rivals, will prevail over others, and pro-social genes will become more common in the population as a whole.
Despite Darwin’s authorship of the idea, selection at the level of groups, known as group selection for short, is controversial among evolutionary biologists. It has recently drawn the support of notable champions, such as David Sloan Wilson and Edward O. Wilson, but they are at present in a minority. Most evolutionary biologists believe that although natural selection could in theory operate at the group level in special circumstances, its principal operation takes place at the level of individuals.
The argument that follows shows how group selection, if it has occurred in human evolution, could account well for the evolution of religious and other social behaviors in early human groups. Human social behaviors, such as the deeply ingrained moral instincts described earlier, exist and must have evolved somehow. If they did not do so through group selection, then it was through some other evolutionary process, but group selection, despite the uncertainties surrounding it, is the process presented here.
Here is how Darwin said group selection would work:
“It must not be forgotten that although a high standard of morality gives but a slight or no advantage to each individual man and his children over the other men of the same tribe, yet that an increase in the number of well-endowed men and an advancement in the standard of morality will certainly give an immense advantage to one tribe over another. A tribe including many members who, from possessing in a high degree the spirit of patriotism, fidelity, obedience, courage, and sympathy, were always ready to aid one another, and to sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection. At all times throughout the world tribes have supplanted other tribes; and as morality is one important element in their success, thestandard of morality and the number of well-endowed men will thus everywhere tend torise and increase.” 68
This deep insight carries political implications that some biologists and others have found unwelcome. It could be extended to imply that might is right, that victorious nations are more virtuous than those they vanquish, or that the rule of colonial powers is justified. But Darwin neither said nor implied any of the above.
Whether or not with extraneous political reasons, many evolutionary biologists have looked askance at the idea of group selection. They still embrace the position put forward by George Williams and others that group selection might occur to some small account, but its contribution will always be minor compared with individual selection.
Biologists developed several more specific reasons for thinking they could do without group selection to explain human social behaviors such as altruism. One was the theory of inclusive fitness, or kin selection, produced by William Hamilton, who argued that altruism could spread among groups of closely related individuals. Even if an individual perished, genes identical to his own would survive, on average, in the children and siblings for whom he laid down his
The answer that occurred to Darwin was that natural selection could take place at the level of a group of people, not just at the individual level. A society full of altruists, say of men ready to sacrifice their lives in battle, would be very likely to prevail over a less well-motivated group. Just as some individuals within a group will be more successful than others and leave more progeny, so it is in the struggle between groups. The more unified societies, those whose members contain a larger proportion of pro-social genes than do their rivals, will prevail over others, and pro-social genes will become more common in the population as a whole.
Despite Darwin’s authorship of the idea, selection at the level of groups, known as group selection for short, is controversial among evolutionary biologists. It has recently drawn the support of notable champions, such as David Sloan Wilson and Edward O. Wilson, but they are at present in a minority. Most evolutionary biologists believe that although natural selection could in theory operate at the group level in special circumstances, its principal operation takes place at the level of individuals.
The argument that follows shows how group selection, if it has occurred in human evolution, could account well for the evolution of religious and other social behaviors in early human groups. Human social behaviors, such as the deeply ingrained moral instincts described earlier, exist and must have evolved somehow. If they did not do so through group selection, then it was through some other evolutionary process, but group selection, despite the uncertainties surrounding it, is the process presented here.
Here is how Darwin said group selection would work:
“It must not be forgotten that although a high standard of morality gives but a slight or no advantage to each individual man and his children over the other men of the same tribe, yet that an increase in the number of well-endowed men and an advancement in the standard of morality will certainly give an immense advantage to one tribe over another. A tribe including many members who, from possessing in a high degree the spirit of patriotism, fidelity, obedience, courage, and sympathy, were always ready to aid one another, and to sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection. At all times throughout the world tribes have supplanted other tribes; and as morality is one important element in their success, thestandard of morality and the number of well-endowed men will thus everywhere tend torise and increase.” 68
This deep insight carries political implications that some biologists and others have found unwelcome. It could be extended to imply that might is right, that victorious nations are more virtuous than those they vanquish, or that the rule of colonial powers is justified. But Darwin neither said nor implied any of the above.
Whether or not with extraneous political reasons, many evolutionary biologists have looked askance at the idea of group selection. They still embrace the position put forward by George Williams and others that group selection might occur to some small account, but its contribution will always be minor compared with individual selection.
Biologists developed several more specific reasons for thinking they could do without group selection to explain human social behaviors such as altruism. One was the theory of inclusive fitness, or kin selection, produced by William Hamilton, who argued that altruism could spread among groups of closely related individuals. Even if an individual perished, genes identical to his own would survive, on average, in the children and siblings for whom he laid down his
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