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Egalitarian Revolution In The Pleistocene?
Although anthropologists and evolutionary biologists are still debating this
question, a new study, published in the open-access journal PLoS ONE,
supports the view that the first egalitarian societies may have appeared
tens of thousands of years before the French Revolution, Marx, and Lenin.
These societies emerged rapidly through intense power struggle and their
origin had dramatic implications for humanity. In many mammals living in
groups, including hyenas, meerkats, and dolphins, group members form
coalitions and alliances that allow them to increase their dominance status
and their access to mates and other resources. Alliances are especially
common in great apes, some of whom have very intense social life, where they
are constantly engaged in a political maneuvering as vividly described in
Frans de Waal's "Chimpanzee politics".
In spite of this, the great apes' societies are very hierarchical with each
animal occupying a particular place in the existing dominance hierarchy.
A major function of coalitions in apes is to maintain or change the
dominance ranking. When an alpha male is well established, he usually can
intimidate any hostile coalition or the entire community.
In sharp contrast, most known hunter-gatherer societies are egalitarian.
Their weak leaders merely assist a consensus-seeking process when the group
needs to make decisions, but otherwise all main political actors behave as
equal. Some anthropologists argue that in egalitarian societies the pyramid
of power is turned upside down with potential subordinates being able to
express dominance over potential alpha-individuals by creating large,
group-wide political alliance.
What were the reasons for such a drastic change in the group's social
organization during the origin of our own "uniquely unique" species? Some
evolutionary biologists theorize that at some point in the Pleistocene,
humans reached a level of ecological dominance that dramatically transformed
the natural selection landscape. Instead of traditional "hostile forces of
nature", the competitive interactions among members of the same group
became the most dominant evolutionary factor. According to this still
controversial view, known as the "social brain" or "Machiavellian
intelligence" hypothesis, more intelligent individuals were able to take
advantage of other members of their group, achieve higher social status,
and leave more offspring who inherited their parent's genes for larger brain
size and intelligence. As a result of this runaway process, the average
brain size and intelligence were increasing across the whole human lineage.
Also increasing were the abilities to keep track of within-group social
interactions, to remember friends and their allies and enemies, and to
attract
and use allies. At some point, physically weaker members of the group
started forming successful and stable large coalitions against strong
individuals who otherwise would achieve alpha-status and usurp the majority
of the crucial resources. Eventually, an egalitarian society was
established. Although some of its components are well supported by data,
this scenario remains highly controversial. One reason is its complexity
which makes it difficult to interpret the data and to intuit the
consequences of interactions between multiple evolutionary, ecological,
behavioral,
and social factors acting simultaneously. It is also tricky to evaluate
relevant time-scales and figure out possible evolutionary dynamics.
A paper published in PLoS ONE today makes steps towards answering these
challenges. The paper is co-authored by Sergey Gavrilets, a theoretical
evolutionary biologist, and two computer scientists, Edgar Duenez-Guzman and
Michael Vose, all from the University of Tennessee, Knoxville.
The researchers built a complex mathematical model describing the process of
alliance formation which they then studied using analytical methods and
large-scale numerical simulations. The model focuses on a group of
individuals who vary strongly in their fighting abilities. If all conflicts
were
exclusively between pairs of individuals, a hierarchy would emerge with a
few strongest individuals getting most of the resource. However, there is
also a tendency (very small initially) for individuals to interfere in an
ongoing dyadic conflict thus biasing its outcome one way or another.
Positive outcomes of such interferences increase the affinities between
individuals while negative outcomes decrease them. Naturally, larger
coalitions have higher probability of winning a conflict.
Gavrilets and colleagues identified conditions under which alliances can
emerge in the group: increasing group size, growing awareness of ongoing
conflicts, better abilities in attracting allies and building complex
coalitions, and better memories of past events.
Most interestingly, the model shows that the shift from a group with no
alliances to one or more alliances typically occurs suddenly, within several
generations, in a phase-transition like fashion. Even more surprisingly,
under certain conditions (which include some cultural inheritance of social
networks) a single alliance comprising all members of the group can emerge
in which resources are divided evenly. That is, the competition among
non-equal individuals can paradoxically result in their eventual equality.
Gavrilets and colleagues argue that such an "egalitarian revolution" could
also follow a change in the mating system that would increase
father-son social bonds or an increase in fidelity of cultural inheritance
of social networks. Interestingly, the fact that mother-daughter social
bonds are often very strong in apes suggests (everything else being the
same) that females could more easily achieve egalitarian societies.
The model also highlights the importance of the presence of outsiders (or
"scapegoats") for stability of small alliances. The researchers suggest
that the establishment of a stable group-wide egalitarian alliance should
create conditions promoting the origin of conscience, moralistic aggression,
altruism, and other cultural norms favoring group interests over those of
individuals. Increasing within-group cohesion should also promote the group
efficiency in between-group conflicts and intensify cultural group
selection.
"Our language probably emerged to simplify the formation and improve the
efficiency of coalitions and alliances," says Gavrilets. The scientists
caution that one should be careful in applying their model to contemporary
humans (whether members of modern societies or hunter-gathers). In
contemporary humans, an individual's decision to join coalitions is strongly
affected by his/her estimates of costs, benefits, and risks associated
as well as by cultural beliefs and traditions. These are the factors
explicitly left outside of the modeling framework.
In humans, a secondary transition from egalitarian societies to hierarchical
states took place as the first civilizations were emerging. How can it be
understood in terms of the model discussed? One can speculate that
technological and cultural advances made the coalition size much less
important in
controlling the outcome of a conflict than the individuals' ability to
directly control and use resources (e.g. weapons, information, food) that
strongly influence the outcomes of conflicts.
Citation:
"Dynamics of Alliance Formation and the Egalitarian Revolution."
Gavrilets S, Duenez-Guzman EA, Vose MD (2008)
PLoS ONE 3(10): e3293. doi:10.1371/journal.pone.0003293
Click here to view abstract online
About PLoS ONE
PLoS ONE is the first journal of primary research from all areas of science
to employ a combination of peer review and post-publication rating and
commenting, to maximize the impact of every report it publishes. PLoS ONE is
published by the Public Library of Science (PLoS), the open-access publisher
whose goal is to make the world's scientific and medical literature a public
resource.
PLOS ONE
Egalitaristã revolutie in Pleistocene? - Egalitarian Revolution In The Pleistocene? - articole medicale engleza - startsanatate