In a population of hawks and doves,the winner of a contest between two individuals earns +20 and the loser earns 0.The cost of injury is -80,while the cost of a display is -10.If the proportion of hawks,h,is 0.4,is the population in a stable equilibrium?
D.The average reward for each type of player is the reward for each type of contest,multiplied by the probability of engaging in that type of contest.
H = -30(0.4)+ 20(0.6)= -12 + 12 = 0

Question

Quizplus · Accepted Answer

In a dove versus dove contest,one of the doves will display and win,earning +10 (reward minus cost of display),while the other will display and lose,earning -10 (cost of display).The average reward is therefore:
10-10/2= 0
In a hawk versus hawk contest,one of the hawks will fight and win,earning +20,while one will fight and lose,and earning -80.The average reward is therefore:
20-80/2= -30
In a hawk versus dove contest,the dove will always retreat immediately,earning 0,while the hawk will always win earning +20.
If h=0.4,(1-h)=0.6.Stable equilibrium is reached when the average reward for a hawk,H,equals the average reward for a dove,

In a Population of Hawks and Doves,the Winner of a Contest