Cooperation and Conflict

Hawk-Dove & Bourgeois

Evolutionary game theory analyzes interactions where your payoff depends on what others do. The Hawk-Dove game models conflict over a shared resource: Hawks always escalate and fight, while Doves display but retreat before injury.

Neither pure strategy is stable alone. Doves get invaded by Hawks, and Hawks pay heavy injury costs that let Doves thrive. The population settles at a mixed Evolutionarily Stable Strategy (ESS): a strategy that, once common, cannot be beaten by any rare alternative.

$$\text{ESS: no rare strategy can invade}$$

In some species, the Bourgeois strategy emerges as the ESS instead: fight if you are the resource owner, retreat if you are the intruder.

Prisoner's Dilemma & Tit-for-Tat

The Prisoner's Dilemma models cooperation between non-relatives. Mutual cooperation yields the best collective payoff, but each individual is tempted to defect for a higher personal payoff.

Robert Axelrod's computer tournaments found that a simple strategy—Tit-for-Tat (cooperate first, then mirror the partner's previous move)—outperformed complex rivals by being nice, retaliatory, forgiving, and clear.

Common pitfall: Assuming the winning strategy must be cunning and deceptive. Transparent, reciprocal strategies that start cooperatively consistently outperform exploitative ones.