Suppose a shared resource is replenished at a limited rate. How much should you take? Should you be selfish and take as much as you want, or should you be cooperative and take what you need, hoping that more will be available in the future?
Why do people volunteer for dangerous jobs such as soldier or policeman? Why hasn't evolution caused altruists to become extinct?
While the altruistic personality is motivated to help the needy even at a personal cost, the vindictive personality is motivated to punish evil doers, even at a personal cost. Why do we still find this trait in our population?
Beyond cooperation, spontaneous teamwork involves agents assuming roles in a system-level process.
Bees
Prisoner's Dilemma Tournaments