The evolution of altruism (David Sloan Wilson and Edward O Wilson)
November 6th 2007 02:20
I made some remarks (or rather, quoted a chunk) earlier on Darwin and the evolution of morality.
Well, here's a supplement.
A summary of an article -- "Survival of the selfless" by David Sloan Wilson and Edward O Wilson (New Scientist, Saturday 3 November 2007, p 42; the article was in turn an abridgment of a review appearing in the December issue of The Quarterly Review of Biology).
* Darwin proposed that instincts towards altruism evolve from competition between groups. That is, evolution occurs at multiple levels (groups competing with groups as well as individuals competing with individuals). "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... an advancement in the standard of morality will certainly give an immense advantage to one tribe over another." -- The Descent of Man, 1871.
* In the 1960s, the idea that there are any group-related adaptations became unfashionable, on the basis that "the evolutionary force favouring altruism is almost invariably weak compared with within-group selection, the evolutionary force favouring selfishness." Apparent altruistic behaviour was explained instead by inclusive fitness (kin selection) theory, evolutionary game theory, and selfish gene theory.
(* If I were more philosophically inclined, I'd want to ask what defines "altruistic behaviour". Isn't it equally "altruistic" regardless of whether it evolved through kin selection or group selection or whatever? But anyway...)
* The arguments against group selection were: (1) that it's "theoretically implausible" as a significant evolutionary force; (2) that there's no empirical evidence to support it; and (3) that there are robust alternatives.
* Attacking this view, Wilson and Wilson argue:
-- (1) that the implausibility of group selection as a significant evolutionary force was based on faulty models. "[T]hese early models were published before the desktop computing revolution, the study of complex interactions, and the appreciation of such things as social control and gene-culture coevolution.... For example, the early models assumed that genes code directly for behaviours... [Whereas] Behavioural variation between groups can be large even when genetic variation between them is small -- for instance, when members within a group imitate each other or impose distinct social norms... A model published in 2004 even confirms the plausibility of a hypothesis proposed by zoologist VC Wynne-Edwards in 1962 -- that animals might evolve to reduce their fertility to avoid overexploiting their resources".
-- (2) that there is now evidence that inter-group selection actually happens. Studies of microbes are cited, and mention is made of the fact that only some female lions provide territorial defence, although "Leaders do not gain additional benefits from leading, but they do provide an opportunity for laggards to gain a free ride".
-- (3) that the other theories developed to explain apparent altruism as individual selfishness turn out to assume multilevel selection. "First, they must assume the existence of multiple groups, because social interactions almost invariably take place among small fractions of the total population... Second, all models must identify the appropriate groups for any particular trait. This is because the fitness of an individual depends upon the others with whom it interacts, which must be appropriately specified... If individuals interact in groups of five, then two-person game theory won't do. Third, when fitnesses are compared within and among groups, the behaviours labelled cooperative or altruistic are almost invariably selectively disadvantageous within groups and thus can only evolve by virtue of between-group selection."
* Mention is made, inter alia, of the idea of "extended phenotypes", developed by Richard Dawkins -- "that genes can have effects that extend beyond the body of the individual, such as a beaver dam." Wilson and Wilson claim, in reply, that the genes that "cause beavers to build dams are still at a local disadvantage compared with genes in beavers in the same pond that don't build dams. So the concept of extended phenotypes does not solve the problem that Darwin identified".
* "Accepting multilevel selection has profound implications. It means we can no longer regard the individual as a privileged level of the biological hierarchy. Adaptations can potentially evolve at any level, from genes to ecosystems. Moreover, the balance between levels of selection is not fixed but can itself evolve and when between-group selection becomes sufficiently strong compared with within-group selection in a given population, a major transition occurs and the group becomes a higher-level organism in its own right."
* "Ironically, the rejection of group selection made it heresy to think of groups as being like organisms. Now it has emerged that the organisms of today are literally the groups of past ages."
* Mention is made of bee colonies -- it may be better to think of each colony as a superorganism; traits that contribute to colony fitness are often selectively disadvantageous within colonies. And "[h]uman evolution, too, has all the hallmarks of a major transition. Anyone who studies humans must acknowledge our groupish nature and the importance of between-group interactions. Explaining these obvious facts without invoking group selection involves needless contortions."
* "According to anthropologist Christopher Boehm, a key event in early human evolution was a form of enforced egalitarianism that made it difficult for some individuals to dominate others within their own group... A common scenario for human evolution begins with the evolution of sophisticated cognitive abilities... However, a 2005 review suggests it would be more reasonable for the sequence to be reversed (Behavioral and Brain Sciences, vol 28, p 675). Our capacities for symbolic thought and communication are communal activities that probably came after a shift in the balance between levels of selection."
Well, here's a supplement.
A summary of an article -- "Survival of the selfless" by David Sloan Wilson and Edward O Wilson (New Scientist, Saturday 3 November 2007, p 42; the article was in turn an abridgment of a review appearing in the December issue of The Quarterly Review of Biology).
***
* Darwin proposed that instincts towards altruism evolve from competition between groups. That is, evolution occurs at multiple levels (groups competing with groups as well as individuals competing with individuals). "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... an advancement in the standard of morality will certainly give an immense advantage to one tribe over another." -- The Descent of Man, 1871.
'Dawkins coined the term selfish gene as a provocative way of expressing the gene-centered view of evolution, which holds that evolution is best viewed as acting on genes, and that selection at the level of organisms or populations almost never overrides selection based on genes.'
(* If I were more philosophically inclined, I'd want to ask what defines "altruistic behaviour". Isn't it equally "altruistic" regardless of whether it evolved through kin selection or group selection or whatever? But anyway...)
* The arguments against group selection were: (1) that it's "theoretically implausible" as a significant evolutionary force; (2) that there's no empirical evidence to support it; and (3) that there are robust alternatives.
* Attacking this view, Wilson and Wilson argue:
-- (1) that the implausibility of group selection as a significant evolutionary force was based on faulty models. "[T]hese early models were published before the desktop computing revolution, the study of complex interactions, and the appreciation of such things as social control and gene-culture coevolution.... For example, the early models assumed that genes code directly for behaviours... [Whereas] Behavioural variation between groups can be large even when genetic variation between them is small -- for instance, when members within a group imitate each other or impose distinct social norms... A model published in 2004 even confirms the plausibility of a hypothesis proposed by zoologist VC Wynne-Edwards in 1962 -- that animals might evolve to reduce their fertility to avoid overexploiting their resources".
-- (2) that there is now evidence that inter-group selection actually happens. Studies of microbes are cited, and mention is made of the fact that only some female lions provide territorial defence, although "Leaders do not gain additional benefits from leading, but they do provide an opportunity for laggards to gain a free ride".
-- (3) that the other theories developed to explain apparent altruism as individual selfishness turn out to assume multilevel selection. "First, they must assume the existence of multiple groups, because social interactions almost invariably take place among small fractions of the total population... Second, all models must identify the appropriate groups for any particular trait. This is because the fitness of an individual depends upon the others with whom it interacts, which must be appropriately specified... If individuals interact in groups of five, then two-person game theory won't do. Third, when fitnesses are compared within and among groups, the behaviours labelled cooperative or altruistic are almost invariably selectively disadvantageous within groups and thus can only evolve by virtue of between-group selection."
* "Accepting multilevel selection has profound implications. It means we can no longer regard the individual as a privileged level of the biological hierarchy. Adaptations can potentially evolve at any level, from genes to ecosystems. Moreover, the balance between levels of selection is not fixed but can itself evolve and when between-group selection becomes sufficiently strong compared with within-group selection in a given population, a major transition occurs and the group becomes a higher-level organism in its own right."
* "Ironically, the rejection of group selection made it heresy to think of groups as being like organisms. Now it has emerged that the organisms of today are literally the groups of past ages."
* Mention is made of bee colonies -- it may be better to think of each colony as a superorganism; traits that contribute to colony fitness are often selectively disadvantageous within colonies. And "[h]uman evolution, too, has all the hallmarks of a major transition. Anyone who studies humans must acknowledge our groupish nature and the importance of between-group interactions. Explaining these obvious facts without invoking group selection involves needless contortions."
* "According to anthropologist Christopher Boehm, a key event in early human evolution was a form of enforced egalitarianism that made it difficult for some individuals to dominate others within their own group... A common scenario for human evolution begins with the evolution of sophisticated cognitive abilities... However, a 2005 review suggests it would be more reasonable for the sequence to be reversed (Behavioral and Brain Sciences, vol 28, p 675). Our capacities for symbolic thought and communication are communal activities that probably came after a shift in the balance between levels of selection."
***
David Sloan Wilson (1949-)
Edward O Wilson (1929-)
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Comment by Damo
Sort of reminded me of when I was studying biology. The catch phrase for the lessons was 'fitness for purpose'. In a non-exact science like biology there is a tendancy for people to look for patterns and correlations o formulate a theory.
In evolutionary terms the question of 'fitness for purpose' directly relates the design of any aspect of a living entity to the function that it performs. Wing have feathers because that best suits flight, Moles have claws because that suits digging. Without the direct relationship between form and function there is no evolutionary mechanism to to create any unique biological feature.
The difficulty I do have in Ultruism is that I can build a case to justify it and I can build a case to prove it is unnatural depending upon which evidence I select and how I interpret it. Is what you call an ultruistic act the same as what I call one? Or are we being clouded in judgement by the emotional overtones? Are our conclusions justified or based upon supositions?
Perhaps we may be looking to the inprecise sciences to find precise answers?
Comment by Lilla
From The Home Front
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An interesting read and I'm not sure I 'get it' all, for some of it rambles a bit... but...just a little left of field here: There is no doubt that fitness creates purpose as a means to itself. Without fitness there is no purpose, only decay.
As for group fitness, that too is lessened through polluted environemnts, again leading to decay and lack of purpose.
So, can we conclude that fitness becomes it's own purpose and chooser, in order to fulfil it's single purpose as the vehicle of evolution?
Lilla ...