Making Altruism Pay: How Reputation Became an Asset in Evolutionary Multi-Agent Simulation

We demonstrate that reputation can be transformed from a liability to an asset under specific economic conditions. Using a novel fitness metric S_life = accuracy / avg cost, we evolved agents with five heritable traits: threshold, risk, generosity, selfishness, and cooperation. Through nine experimental phases (124 successful runs, validated over 1000 ticks), we achieved a positive correlation between reputation and survival (r = +0.472), a 12-fold increase in generosity (0.028 → 0.329), and 100% system stability. The key success formula comprises rare interactions (10%), cheap help (3 energy), high reputation bonuses (+12 energy/tick), and a low multiplier (0.2). Our results demonstrate that altruism can evolve when reputation provides tangible, immediate benefits that outweigh the costs of helping.