Various signaling probs with perfect screening

[davidrpugh]

Case where the IPD condition is not satisfied:

In the plots below, I use the following payoff matrix:

payoffs = {'PiaA': 9.0, 'PiAA': 5.0, 'Piaa': 3.0, 'PiAa': 2.0}

Note the for this payoff matrix the iterated prisoner's dilemma (IPD) condition (i.e., 2 * PiAA > PiaA + PiAa is not satisfied.

Case where the IPD condition is satisfied:

In the plots below, I use the following payoff matrix:

payoffs = {'PiaA': 7.0, 'PiAA': 5.0, 'Piaa': 3.0, 'PiAa': 2.0}

Note the for this payoff matrix the iterated prisoner's dilemma (IPD) condition (i.e., 2 * PiAA > PiaA + PiAa is satisfied. I am not sure that I understand/believe the results in these plots. They seem to indicate that balanced polymorphism can exist, but with equilibrium shares that seem to equal the initial conditions.

@markeschaffer , @PaulSeabright your thoughts?

[markeschaffer]

Perfect screening supports pure-subpopulation-equilibria if the initial conditions are pure subpopulations, since GA males always match with GA females, similarly with ga males and females, and the subpopulations breed true. Probably worth looking at "almost perfect screening" (e=0.99 or somesuch) to see if this is a knife-edge results.

[davidrpugh]

I suspect that it is a knife-edge result. I did not run simulations for eA=ea=0.99 however, I did run simulations for eA=ea=0.9...