in which having a different behavior than one's partner produces a higher payoff. Doves cooperate by sharing resources but retreat when challenged. Hawks do not cooperate. They are ready to fight to avoid leaving an interaction empty-handed. A Hawk gets the entire resource when facing a Dove but suff

like those Israel has carried out against Irca and Syria. Iran, for its part, claims the number of casualties it might sustain will be tolerable. "Hawks on both sides, Israel and the United States, and Iran, want to underplay the level of casualties," says Ali Ansari, an Iran expert at Scotland's Un

like those Israel has carried out against Ing and Syria. Iran, for its part, claims the number of casualties it might sustain will be tolerable. "Hawks on both sides, Israel and the United States, and Iran, want to underplay the level of casualties," says Ali Ansari, an Iran expert at Scotland's U

k that the success or failures of their regional policies have much to do with what the U.S. will or will not do. They are writing Washington off. Hawks and doves alike, none of the Iranians interviewed in the Journal's saw fit to mention America in their calculations. Iraq, Saudi Arabia, and even t

ualitative I. Nowak MA. May RM (1992) Emlutionay gams and mad chaos. Nature BOA 2. Killingback T. Ociegia M (1996) Spatial evolutionary game showy: Hawks and doves malted. Prot. FL Soc. B 2634137421135-1144. 3. Seat., G. Take C (1996) Evolutionary Mantis ek.na Vine on a mime laths Phys. Rev. E. 56(1

as freezing and feigning death. For example, a mouse freezes when it senses a predator nearby, becoming "as still as a mouse" to avoid detection. Hawks have extremely good eyesight and can pick up the slightest movement, even those of a mouse's normal breathing. If a hawk is cir- cling in a field ov

14 6.2 Mixed games with 2 strategies 119 6.3 Mixed games with two pure strategies 122 6.3.1 A resealed payoff matrix 125 6.3.2 Example: Hawks and Doves 126 6.4 A mixed 3-game: Cooperators, Defectors, Loners 130 6.5 Mixed games with n pure strategies 135 6.6 Conclusion 136 B

. 0, the mixed phase extends to the quarter-plane a > 0, > 0. For large mutation ratesµ —• co, however, the mixed phase disappears. 6.3.2 Example: Hawks and Doves As an example, we consider the Hawk-Dove game (Maynard-Smith 1982, Houston Mcishunara 1988, Houston Sc McNamara 1991, IvIesterton-Gibbons