126 research outputs found
Evolution of Human-like Social Grooming Strategies regarding Richness and Group Size
Human beings tend to cooperate with close friends, therefore they have to
construct strong social relationships to recieve cooperation from others.
Therefore they should have acquired their strategies of social relationship
construction through an evolutionary process. The behavior of social
relationship construction is know as "social grooming." In this paper, we show
that there are four classes including a human-like strategy in evolutionary
dynamics of social grooming strategies based on an evolutionary game
simulation. Social relationship strengths (as measured by frequency of social
grooming) often show a much skewed distribution (a power law distribution). It
may be due to time costs constraints on social grooming, because the costs are
too large to ignore for having many strong social relationships. Evolution of
humans' strategies of construction of social relationships may explain the
origin of human intelligence based on a social brain hypothesis. We constructed
an individual-based model to explore the evolutionary dynamics of social
grooming strategies. The model is based on behavior to win over others by
strengthening social relationships with cooperators. The results of
evolutionary simulations show the four classes of evolutionary dynamics. The
results depend on total resources and the ratio of each cooperator's resource
to the number of cooperators. One of the four classes is similar to a human
strategy, i.e. the strategies based on the Yule--Simon process of power law.Comment: 21 pages, 10 figure
Strategy intervention for the evolution of fairness
Masses of experiments have shown individual preference for fairness which
seems irrational. The reason behind it remains a focus for research. The effect
of spite (individuals are only concerned with their own relative standing) on
the evolution of fairness has attracted increasing attention from experiments,
but only has been implicitly studied in one evolutionary model. The model did
not involve high-offer rejections, which have been found in the form of
non-monotonic rejections (rejecting offers that are too high or too low) in
experiments. Here, we introduce a high offer and a non-monotonic rejection in
structured populations of finite size, and use strategy intervention to
explicitly study how spite influences the evolution of fairness: five
strategies are in sequence added into the competition of a fair strategy and a
selfish strategy. We find that spite promotes fairness, altruism inhibits
fairness, and the non-monotonic rejection can cause fairness to overcome
selfishness, which cannot happen without high-offer rejections. Particularly
for the group-structured population with seven discrete strategies, we
analytically study the effect of population size, mutation, and migration on
fairness, selfishness, altruism, and spite. A larger population size cannot
change the dominance of fairness, but it promotes altruism and inhibits
selfishness and spite. Intermediate mutation maximizes selfishness and
fairness, and minimizes spite; intermediate mutation maximizes altruism for
intermediate migration and minimizes altruism otherwise. The existence of
migration inhibits selfishness and fairness, and promotes altruism; sufficient
migration promotes spite. Our study may provide important insights into the
evolutionary origin of fairness.Comment: 15 pages, 7 figures. Comments welcom
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