Looks like they deliberately use a conservative formulation of the “detrimental characteristics of a PD.” Both players are required to have a dominant strategy, that leads to a situation where both are worse off than the optimal square.
A more expansive formulation would be something like “there is a Nash equilibrium that is not Pareto optimal.” If the preference-ranking version of the PD is something like [[11],[24]][[42],[33]], this means that we’d also notice something interesting about the game [[22],[14]][[41],[43]], etc.
there is a Nash equilibrium that is not Pareto optimal
Like Stag Hunt.
What they argue is that mechanisms for producing mutual cooperation in games like your more expansive formulation but that don’t match the deliberately conservative formulation might have been important in the evolution of cooperativeness.
Looks like they deliberately use a conservative formulation of the “detrimental characteristics of a PD.” Both players are required to have a dominant strategy, that leads to a situation where both are worse off than the optimal square.
A more expansive formulation would be something like “there is a Nash equilibrium that is not Pareto optimal.” If the preference-ranking version of the PD is something like [[11],[24]][[42],[33]], this means that we’d also notice something interesting about the game [[22],[14]][[41],[43]], etc.
I find the narrow definition of “PD-type” games useful. You raise a good question though, to which the author’s answer is
Like Stag Hunt.
What they argue is that mechanisms for producing mutual cooperation in games like your more expansive formulation but that don’t match the deliberately conservative formulation might have been important in the evolution of cooperativeness.