Evolutionary Game Theory (EGT) EGT applies game theory to biological populations, replacing "rational decision-making" with natural selection. Strategies are heritable traits, and payoffs are measured in Darwinian fitness (reproductive success).

Key Concepts

• Evolutionarily Stable Strategy (ESS): Introduced by Maynard Smith and Price to analyze animal conflict (e.g., the Hawk-Dove game), an ESS is a strategy that, if adopted by a population, cannot be invaded by a rare mutant. While an ESS implies a Nash Equilibrium (a best response to itself), not all Nash Equilibria are evolutionarily stable.

• Replicator Dynamics: This models how the frequency of a strategy changes over time. Strategies yielding fitness above the population average increase in frequency. This dynamic view reveals that systems may not always reach a stable po ...