In a game of interations, co-operation makes sense. That is, when you know that other players have memory and can apply that to the future, then reputation enters and taking advantage turns into a losing strategy. It could also pay to take more aggressive strategies if the strategies of others were extremely aggressive or extremely passive. It's a game of competing strategies in communities of strategies. The major finding when the SFI methods were used, as last heard by me at any rate, is that the value of apology and generous interpretation can add significantly in many settings.
Intelligence is the underlying organisational principle of the universe.