Pacific Institute for the Mathematical Sciences - PIMS

The emergence and maintenance of cooperative behavior that is
beneficial to others but costly to the individual represents a major
conundrum in evolutionary biology. Punishment represents an efficient
mechanism to stabilize and maintain cooperation in social dilemmas and
is ubiquitous in animal and human societies - ranging from toxin
producing microorganisms to law enforcement institutions - but it
remains unresolved how initially rare costly punishment can gain a
foothold and spread through the population. In nature, animals and
humans often select their interaction partners or adjust their behavior
in response to them. In the simplest case they simply refuse to
participate in risky enterprises. Such voluntary participation in
social dilemmas is an efficient mechanism to prevent deadlocks in
states of mutual defection, and thus represents a potent promoter of
cooperation that nevertheless fails to stabilize it. However, the
combined efforts of punishment and volunteering may change the odds in
favor of cooperation. Interestingly, even the combined efforts fail in
infinite populations, but provide a most efficient mechanism to
stabilize cooperation (and punishment) in the stochastic dynamics of
finite populations under mutation and selection. Thus the freedom to
withdraw leads to prosocial coercion. This implements Hardin's
principle: mutual coercion mutually (and voluntarily) agreed upon.

MITACS Math Biology Seminar 2007