Maynard Smith (1984)
A Qualitative Example:
“Hawk” is not stable, because a mutant dove does better against
a hawk (assuming the payoffs here) than another hawk.
These are not hawks and doves but 2 animals of the same species
competing with different strategies.
“Hawk” is aggressive and dangerous
“Dove” is unagressive but safe.
theory is about an “Evolutionarily Stable Strategy” (ESS)
which applies to a population.
Similarly “Dove” is not itself an ESS because a mutant
hawk would have the advantage in a population of doves.
If all animals are either one or the other the population
would evolve to 0.33 hawks and 0.67 doves.
Or a “mixed” ESS is stable if all animals are hawks a third
of the time and doves for the other two third.
This could happen if animals learn from experienced
pay-offs to be hawkish a third of the time.
Learning is necessary for reciprocal altruism in social groups.
(e.g. the “tit-for-tat” model).