Figure 5
From: Egoistic punishment outcompetes altruistic punishment in the spatial public goods game
The frequencies of punishers as a function of punishment fines in four punishment mechanisms at different costs (\(\alpha\)) and synergy factors (r). Red solid circles represent egoistic pool punisher (\(P_S\)) and blue circles mean egoistic peer punisher (\(P_B\)). Black solid squares represent altruistic pool punisher (\(P_G\)) and black hollow squares mean altruistic peer punisher (\(P_R\)). Results show survivability of \(P_S\) and \(P_G\) are stronger than that of \(P_B\) and \(P_R\), but adaptability is worse. Moreover, \(P_S\) can survive better in lower-fine areas than \(P_G\). After the peer punishers occupy the population, they behave like pure cooperators and are easily invaded by pure cooperators, so they cannot be identified when there is no defector. Therefore, we marked the first and last time the beta value of the population occupied by the peer punishers in the graphs, while ignoring the intermediate value for easy observation.
