Slow emergence of cooperation for win-stay lose-shift on trees (Q2384146)

The paper under review considers a group of agents on a graph who repeatedly play the prisoner's dilemma (PD) game with their neighbors. The players here apply the win-stay lose-shift strategy. The authors here analyse the rate of convergence to cooperation (i.e. to the all-cooperate state) in terms of the size and structure of the graph. They show that on some expander graphs and bounded-degree trees, this iterated PD game exhibits an exponentially slow converge to cooperation.