Criticality as key-concept to understand social norms' dynamics in networks

Starting from experimental results, we demonstrate by means of simulations and theoretical analysis that human behaviour is near a critical point when the subjects play at a Prisoner's Dilemma Game in controlled conditions. The criticality of the dynamics allows the community to maximize the global fitness, fostering cooperation and punishing free riders (making the system also resilient to the invasion of defectors). This positive effect of criticality is so strong to hide significant influence of the network structure, even though this result will have to be confirmed also for kinds of interactions different from the Prisoner's Dilemma.