Fig. 2.

Impact of model parameters on patterns of kin discrimination. Here we focus on a region of parameter space in which player 1 should carry out the selfish act when unopposed, but in which player 2 may do best to resist (i.e., b₁ – c₁ – r b₂ > 0). We show the probability that, at equilibrium, the actor attempts a selfish act, as a function of relatedness, when c₂ is drawn from a normal distribution with specified mean and SD equal to 0.2. (A) Probability that a selfish act is attempted at equilibrium, assuming that b₁ = 1, c₁ = 0.1, b₂ = 0.5, and mean c̄₂ as specified for the plotted curves. (B) Probability that a selfish act is attempted at equilibrium, assuming that b₁ = 1, c₁ = 0.1, c̄₂ = 0.5, and b₂ is as shown in the plot.