A good overview of Group Selection is given in http://
www.robertwilliams.org/tpp/tpp_v1-12supp.html
In populations composed of groups characterized by a higher rate of
interaction among members than between insiders and outsiders,
evolutionary processes may be decomposed into between-group and
within-group selection effects (Lewontin 1965, Price 1972, Crow and
Kimura 1970, Uyenoyama and Feldman 1980). Where the rate of
replication of a trait depends on the frequency of the trait in the
group, and where group differences in trait frequencies are
substantial and persistent, group selection contributes to the pace
and direction of evolutionary change. Thus an altruistic trait that
confers fitness advantages on other members of a group while imposing
fitness costs on its bearer could evolve if the positive between-
group selection effects are sufficiently strong to outweigh the
negative within-group selection effects. Group selection works by
exactly the same process as kin selection: altruism may evolve if the
level of assortative pairing is sufficiently high. It does not matter
whether assortative pairing occurs because individuals are more
likely to be paired with relatives, or because individuals interact
in groups and group compositions differ.
As to some interesting examples of morality from our animal world
Marc Hauser (1992) showed that rhesus monkeys in captivity punish
those who do not vocalize to advertise food discovery. Monkeys who
remain silent, thereby enjoying exclusive access to a desirable food
source for a longer period of time before others compete for a share,
do indeed attract fewer conspecifics to the site, but those who do
detect the food source are sufficiently punitive toward the original
discoverer that the latter manages to consume only a fraction of what
a vocalizer is permitted to consume by a larger group of conspecifics
(2.8 pieces of coconut for the silent discoverer, compared with 4.9
for the vocalizer). In a more recent study Hauser (2003) shows that
Cotton-top Tamarin monkeys can distinguish between altruistic and
selfish (mutualistic) sharing of food, and that they systematically
reward altruistic acts with reciprocal acts of kindness. Finally,
Brosnan and de Waal (2003) show that brown capuchin monkeys compare
payoffs to themselves with payoffs to other monkeys, and reject
valuable food resources and opportunities for profitable exchange
when they perceive conspecifics who are getting better deals.
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Received on Tue Oct 31 21:08:10 2006
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