Emergence of social cohesion in a model society of greedy, mobile individuals

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 108; no. 28; pp. 11370 - 11374
• Main Authors: Roca, Carlos P, Helbing, Dirk
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 12.07.2011; National Acad Sciences
• Subjects: Attitudes; behavior change; Behavior modeling; coevolution; Cooperation; Cooperative Behavior; economic systems; Emigration and Immigration; Evolution; Game Theory; Habituation; Humans; Interpersonal Relations; learning; Modeling; Models, Psychological; Neighborhoods; Outcomes of education; Population Density; Psychology; Public goods; public services and goods; Social Behavior; social cohesion; Social evolution; Social Sciences; Socialization; society
• DOI: 10.1073/pnas.1101044108
• ISSN: 0027-8424

Human wellbeing in modern societies relies on social cohesion, which can be characterized by high levels of cooperation and a large number of social ties. Both features, however, are frequently challenged by individual self-interest. In fact, the stability of social and economic systems can suddenly break down as the recent financial crisis and outbreaks of civil wars illustrate. To understand the conditions for the emergence and robustness of social cohesion, we simulate the creation of public goods among mobile agents, assuming that behavioral changes are determined by individual satisfaction. Specifically, we study a generalized win-stay-lose-shift learning model, which is only based on previous experience and rules out greenbeard effects that would allow individuals to guess future gains. The most noteworthy aspect of this model is that it promotes cooperation in social dilemma situations despite very low information requirements and without assuming imitation, a shadow of the future, reputation effects, signaling, or punishment. We find that moderate greediness favors social cohesionby a coevolution between cooperation and spatial organization, additionally showing that those cooperation-enforcing levels of greediness can be evolutionarily selected. However, a maladaptive trend of increasing greediness, although enhancing individuals' returns in the beginning, eventually causes cooperation and social relationships to fall apart. Our model is, therefore, expected to shed light on the long-standing problem of the emergence and stability of cooperative behavior.