Re: Article: Group selection, a theory whose time has come...again

"dkomo" <dkomo871@xxxxxxxxxxx> wrote in message
news:DZednfgNLenNoMnanZ2dnUVZ_hOdnZ2d@xxxxxxxxxxxxxx
John Harshman wrote:
dkomo wrote:


John Harshman wrote:


John Wilkins wrote:




Mark Isaak <eciton@xxxxxxxxxxxxx> wrote:





On Sat, 01 Dec 2007 17:10:24 +0000, John Harshman wrote:





dkomo wrote:





[I found this post by Robert Karl Stonjek over on sci.bio.evolution
and
decided to repost it here because it should be of general interest.
Besides, I love to point out instances of the shortcomings of
over-reductionism in evolutionary biology. -- dkomo]


===




Group selection, a theory whose time has come...again

Sociobiology, the discipline founded on Darwin's theory of group
evolution, is in theoretical disarray. In a landmark article for the
December issue of the Quarterly Review of Biology, eminent
evolutionary
scientists David Sloan Wilson and Edward O. Wilson usher in a new
era
in evolutionary science.

"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."

With these words, Charles Darwin proposed an evolutionary
explanation
for morality and pro-social behaviors- individuals behaving for the
good of their group, often at their own expense-that anticipated the
future discipline of Sociobiology. A century after this famous
passage
was published in The Descent of Man (1871), however, Darwin's
explanation based on group selection had become taboo and has not
recovered since.

In a landmark article for The Quarterly Review of Biology,
"Rethinking
the Theoretical Foundation of Sociobiology," eminent evolutionary
scientists David Sloan Wilson and Edward O. Wilson-whose book
Sociobiology:The New Synthesis brought widespread attention to the
field in 1975-call for an end to forty years of confusion and
divergent
theories.

They propose a new consensus and theoretical foundation that affirms
Darwin's original conjecture and is supported by the latest
biological
findings.

Wilson and Wilson trace much of the confusion in the field to the
1960's, when most evolutionists rejected "for the good of the group"
thinking and insisted that all adaptations must be explained in
terms
of individual self-interest. In an even more reductionistic move,
genes
were called "the fundamental unit of selection," as if this was an
argument against group selection. Scientific dogma became entrenched
in
popular culture with the publication of Richard Dawkins' The Selfish
Gene (1976). Although evidence in favor of group selection began
accumulating almost immediately after its rejection, its taboo
status
prevented a systematic re-evaluation of the field until now.

Based on current theory and evidence, Wilson and Wilson show that
natural selection is unequivocally a multilevel process, as Darwin
originally envisioned, and that adaptations can evolve at all levels
of
the biological hierarchy, from genes to ecosystems. They conclude
with
a rallying cry that paraphrases Rabbi Hillel: "Selfishness beats
altruism within groups. Altruistic groups beat selfish groups.
Everything else is commentary,"Wilson and Wilson free sociobiology
to
once again pursue all lines of inquiry within its discipline.

Source: University of Chicago
http://www.physorg.com/news115476686.html

I'd have to read the article. But what group selection needs to
explain
is how groups become altruistic in the face of an ingroup advantage
to
selfishness, and how altruism can be maintained in groups that happen
to
gain it in the face of that advantage. This has always been the
central
problem of group selection, that it's necessarily a weaker force than
individual selection and that we thus have a problem explaining how
it
could prosper in cases where there is conflict between levels.

There has been a great deal of research into just this problem, mostly
using game theory. I really haven't followed it enough to explain it,
so take what follows with a lick of salt. A critical piece is
"altruistic punishment," the willingness to punish someone else who
steps
out of line from the group's norms, even at some personal expense. My
understanding is that once altruistic punishment arises, everything
about
atruism (as we do it) is evolutionarily stable.

That maintains altruism from being subverted by cheaters. It doesn't
explain how it can arise in the first case. I think that group
selection
is not always prohibited by individual selection. It's not always the
case that individual selection is stronger WRT some trait or behaviour
than group selection.


No? The explanation is generally that groups live much longer than
individuals and that individuals are much more numerous than groups,
both of which give individuals a much greater rate of innovation.


Depends on how you define the lifetime of a group. If every time a new
individual is born or another one dies, it's a new group, then the
lifetime of a group is on the same order as an individual lifetime.


Yes, and if you define the lifetime of a group as 10 minutes, it's
really short. But is this definition at all sensible or useful? I think
the answer is clearly "no".

I think so too.

And that applies to your definition too.

No it doesn't. So, how would you define the lifetime of a group?

For
one thing, it's impossible to have selection on a group that no longer
exists if there's any change in its composition.


I'm suggesting that changes in group composition affect the fitnesses of
all its members. Fitness is continually varying. It is not a constant
for an organism, even approximately. There are close interactions among
the group members which produces group selection. The group is a
self-organizing system.


So
cheaters will arise at a much greater rate than will altruistic groups,
for example, making it unlikely for any altruistic group to last long
enough to achieve "fixation".

Not if the individuals of a group are tightly coupled. Then each
individual's fitness depends on the fitnesses of the other members of the
group. Cheaters will decrease the fitness of other individuals while
attempting to enhance their own, so in the end the fitness of the cheater
will decrease as well, hence cheaters will be selected against by group
selection.


I'm afraid you don't understand natural selection.


There's more to group selection than natural selection. There's also
emergence and self-organization.


Consider a colony of beavers. A lazy beaver will decrease the fitness of
the whole colony by laying back and watching the busy beavers do all the
work of felling trees, building dams, and maintaining them. Lazy beavers
will be selected against, while busy beavers will be positively selected.
In this situation, a "cheater" cannot win out against "altruists".


Why? Because you said so? This is the problem with group selection that
you don't seem to understand. If work reduces individual success, then
lazy beavers will increase in frequency in the group, even if that leads
to the group's eventual extinction.

Work doesn't reduce individual success, it increases it.

Now if being lazy is no advantage,
there is no individual selection to oppose group selection, and we have
no problem. But we also wouldn't appear to have any group selection,
just individual advantage in cooperation.


Now of course punishment of cheaters is a
potential way out of this dilemma. But I certainly don't see that as
being a mere detail. And it does at least partially reduce the selection
problem to one of individual selection.

Punishment by other members is an additional mechanism to group
selection. Punishment is on the individual selection level.


And yet group selection doesn't seem to work without it. Certainly your
beaver example doesn't show what you think it does.


Sure it does.

It might if beavers were social animals.... they aren't.
Cj

.

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