[Paleopsych] SW: On Collective Action in Large Groups
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Evolution of Behavior: On Collective Action in Large Groups
http://scienceweek.com/2004/sa041231-2.htm
The following points are made by Ernst Fehr (Nature 2004 432:449):
1) War is a prime example of large-scale within-group cooperation
between genetically unrelated individuals. War also illustrates the
fact that within-group cooperation often serves the purpose of
between-group aggression. Modern states are able to enforce
cooperation in large groups by means of sophisticated institutions
that punish individuals who refuse to meet their duties and reward
those who follow their superiors' commands. The existence of such
cooperation-enhancing institutions is very puzzling from an
evolutionary viewpoint, however, because no other species seems to
have succeeded in establishing large-scale cooperation among
genetically unrelated strangers(1).
2) The puzzle behind this cooperation can be summarized as follows.
Institutions that enhance within-group cooperation typically benefit
all group members. The effect of a single group member on the
institution's success is negligible, but the contribution cost is not
negligible for the individual. Why, therefore, should a
self-interested individual pay the cost of sustaining cooperative
institutions? More generally, why should a self-interested individual
contribute anything to a public good that -- once it exists -- an
individual can consume regardless of whether he contributed or not?
Recent work(2) advances the scope of reputation-based models(3-5) and
demonstrates that individuals' concern for their reputation may be a
solution to this puzzle.
3) Evolutionary psychologists have sought to answer the puzzle of
human collective action for decades. However, progress was limited
because of a lack of commitment to mathematically rigorous theorizing.
Many researchers erroneously thought that the notion of reciprocal
altruism, formalized as a tit-for-tat strategy for two-person
interactions, provides the solution to the problem. It was speculated
that reciprocal altruism "may favor a multiparty altruistic system in
which altruistic acts are dispensed freely among more than two
individuals". However, it is always easier to speculate than to
provide a rigorous model, and the speculation is likely to be wrong in
this case.
4) In the context of the problem of public-goods provision, a
reciprocally altruistic individual is willing to contribute to the
public good if sufficient numbers of other group members are also
willing to contribute. Unfortunately, the presence of only a small
number of defectors quickly causes cooperation to unravel if it is
solely based on conditionally cooperative behavior, because the
defectors induce the conditional cooperators to defect as well. Theory
and simulations suggest that reciprocally altruistic strategies can
only sustain high levels of cooperation in two-person interactions.
Moreover, experimental evidence indicates that cooperation in
public-good games typically unravels because it is not possible to
discipline "free riders" -- those who take advantage of others'
cooperation -- if only conditionally cooperative strategies are
available.
References (abridged):
1. Fehr, E. & Fischbacher, U. Nature 425, 785-791 (2003)
2. Panchanathan, K. & Boyd, R. Nature 432, 499-502 (2004)
3. Nowak, M. A. & Sigmund, K. Nature 393, 573-577 (1998)
4. Leimar, O. & Hammerstein, P. Proc. R. Soc. Lond. B 268, 745-753
(2001)
5. Gintis, H., Smith, E. A. & Bowles, S. J. Theor. Biol. 213, 103-119
(2001)
Nature http://www.nature.com/nature
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Related Material:
ON NATURAL SELECTION, KIN SELECTION, AND ALTRUISM
Notes by ScienceWeek:
In this context, the term "altruism" refers in general to behavior
that benefits another individual, usually of the same species, at the
expense of the agent. The phenomenon is widespread among various
species, and has been interpreted by some as apparently at odds with
Darwinian theory. Theories of altruism in biology are often concerned
with "cost-benefit" analysis as dictated by the logic of natural
selection.
The term "Hamilton's rule" refers to the prediction that genetically
determined behavior that benefits another organism, but at some cost
to the agent responsible, will spread by natural selection when the
relation (rb-c} > 0 is satisfied, where (r) is the degree of
relatedness between agent and recipient, (b) is the improvement of
individual fitness of the recipient caused by the behavior, and (c) is
the cost of the agent's individual fitness as a result of the
behavior. The rule was first proposed by William D. Hamilton
(1936-2000), and Hamilton's theory is often referred to as "kin
selection". As an example: A mutation that affected the behavior of a
sterile worker bee so that she fed her fertile queen but starved
herself would increase the inclusive fitness of that worker because,
while her own fitness decreased, her actions increased the fitness of
a close relative.
The following points are made by Mark Ridley (citation below):
1) Natural selection working on groups of close genetic relatives is
called kin selection. In species in which individuals sometimes meet
one another, such as in social groups, individuals may be able to
influence each other's reproduction. Biologists call a behavior
pattern altruistic if it increases the number of offspring produced by
the recipient and decreases that of the altruist. (Notice that the
term in biology, unlike in human action, implies nothing about the
altruist's intentions: it is a motive-free account of reproductive
consequences.) Can natural selection ever favor altruistic actions
that decrease the reproduction of the actor? If we take a strictly
organismic view of natural selection, it would seem to be impossible.
Yet, as a growing list of natural observations records, animals behave
in an apparently altruistic manner. The altruism of the sterile
'workers' in such insects as ants and bees is one undoubted example.
In such cases, the altruism is extreme, as the workers do not
reproduce in some species.
2) Altruistic behavior often takes place between genetic relatives,
where it is most likely explained by the theory of kin selection. Let
us suppose for simplicity that we have two types of organism,
altruistic and selfish. A hypothetical example might be that, when
someone is drowning, an altruist would jump in and try and save him or
her, whereas the selfish individual would not. The altruistic act
decreases the altruist's chance of survival by some amount which we
call c (for cost), because the altruist runs some risk of drowning.
The action increases the chance of survival of the recipient by an
amount b (for benefit). If the altruists dispensed their aid
indiscriminately to other individuals, benefits will be received by
other altruists and by selfish individuals in the same proportion as
they exist in the population. Natural selection will then favor the
selfish types, because they receive the benefits but do not pay the
costs.
3) For altruism to evolve, it must be directed preferentially to other
altruists. Suppose that acts of altruism were initially given only to
other altruists. In such a case, what would be the condition for
natural selection to favor altruism? The answer is that the altruism
must take place only in circumstances in which the benefit to the
recipient exceeds the cost to the altruist. This relation will hold
true if the altruist is a better swimmer than the recipient, but it
does not logically have to be true (if, for instance, the altruist
were a poor swimmer and the recipients were capable of looking after
themselves, the net result of the altruist's heroic plunge into the
water might merely be that the altruist would drown). If the
recipient's benefit exceeds the altruist's cost, then a net increase
occurs in the average fitness of the altruistic types as a whole. This
condition has only theoretical interest. In practice, it is usually
(maybe always) impossible for altruism to be directed only to other
altruists, because they cannot be recognized with certainty. It may be
possible, however, for altruism to be directed at a class of
individuals that contains a disproportionate number of altruists
relative to their frequency in the population. For example, altruism
may be directed toward genetic relatives. In this case, if a gene for
altruism appears in an individual, it is also likely to be in its
relatives."
Adapted from: Mark Ridley: Evolution. 2nd Edition. Blackwell Science
1996, p.321.
--------------------------------
Related Material:
ON ALTRUISM OF INDIVIDUALS IN INSECT SOCIETIES
The following points are made by Edward O. Wilson (citation below):
1) Altruism is self-destructive behavior performed for the benefit of
others. The use of the word altruism in biology has been faulted by
Williams and Williams (1957), who suggest that the alternative
expression "social donorism" is preferable because it has less
gratuitous emotional flavor. Even so, altruism has been used as a term
in connection with evolutionary argumentation by Haldane (1932) and
rigorous genetic theory by Hamilton (1964), and it has the great
advantage of being instantly familiar. The self-destruction can range
in intensity all the way from total bodily sacrifice to a slight
diminishment of reproductive powers. Altruistic behavior is of course
commonplace in the responses of parents toward their young. It is far
less frequent, and for our purposes much more interesting, when
displayed by young toward their parents or by individuals toward
siblings or other, more distantly related members of the same species.
Altruism is a subject of importance in evolution theory because it
implies the existence of group selection, and its extreme development
in the social insects is therefore of more than ordinary interest. The
great scope and variety of the phenomenon in the social insects is
best indicated by citing a few concrete examples:
a) The soldier caste of most species of termites and ants is virtually
limited in function to colony defense. Soldiers are often slow to
respond to stimuli that arouse the rest of the colony, but, when they
do, they normally place themselves in the position of maximum danger.
When nest walls of higher termites such as Nasutitermes are broken
open, for example, the white, defenseless nymphs and workers rush
inward toward the concealed depths of the nest, while the soldiers
press outward and mill aggressively on the outside of the nest.
Nutting (personal communication) witnessed soldiers of Amitermes
emersoni in Arizona emerge from the nest well in advance of the
nuptial flights, wander widely around the nest vicinity, and
effectively tie up in combat all foraging ants that could have
endangered the emerging winged reproductives.
b) I have observed that injured workers of the fire ant Solenopsis
saevissima leave the nest more readily and are more aggressive on the
average than their uninjured sisters. Dying workers of the harvesting
ant Pogonomyrmex badius tend to leave the nest altogether. Both
effects may be no more than meaningless epiphenomena, but it is also
likely that the responses are altruistic. To be specific, injured
workers are useless for most functions other than defense, while dying
workers pose a sanitary problem.
c) Alarm communication, which is employed in one form or other
throughout the higher social groups, has the effect of drawing workers
toward sources of danger while protecting the queens, the brood, and
the unmated sexual forms.
d) Honeybee workers possess barbed stings that tend to remain embedded
when the insects pull away from their victims, causing part of their
viscera to be torn out and the bees to be fatally injured. A similar
defensive maneuver occurs in many polybiine wasps, including Synoeca
surinama and at least some species of Polybia and Stelopolybia and the
ant Pogonomyrmex badius. The fearsome reputation of social bees and
wasps in comparison with other insects is due to their general
readiness to throw their lives away upon slight provocation.
e) When fed exclusively on sugar water, honeybee workers can still
raise larvae -- but only by metabolizing and donating their own tissue
proteins. That this donation to their sisters actually shortens their
own lives is indicated by the finding of de Groot (1953) that
longevity in workers is a function of protein intake.
f) Female workers of most social insects curtail their own egg laying
in the presence of a queen, either through submissive behavior or
through biochemical inhibition. The workers of many ant and stingless
bee species lay special trophic eggs that are fed principally to the
larvae and queen.
g) The "communal stomach", or distensible crop, together with a
specially modified proventriculus, forms a complex storage and pumping
system that functions in the exchange of liquid food among members of
the same colony in the higher ants. In both honeybees and ants, newly
fed workers often press offerings of ingluvial food on nestmates
without being begged, and they may go so far as to expend their supply
to a level below the colony average.
2) These diverse physiological and behavioral responses are difficult
to interpret in any way except as altruistic adaptations that have
evolved through the agency of natural selection operating at the
colony level. The list by no means exhausts the phenomena that could
be placed in the same category.
Adapted from: Edward O. Wilson: The Insect Societies. Harvard
University Press 1971, p.321.
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