The coevolution of loyalty and cooperation

— Humans are inclined to engage in long-lasting relationships whose stability does not only rely on cooperation, but often also on loyalty — our tendency to keep interacting with the same partners even when better alternatives exist. Yet, what is the evolutionary mechanism behind such irrational behavior? Furthermore, under which conditions are individuals tempted to abandon their loyalty, and how does this affect the overall level of cooperation? Here, we study a model in which individuals interact along the edges of a dynamical graph, being able to adjust both their behavior and their social ties. Their willingness to sever interactions is determined by an individual characteristic and subject to evolution. We show that defectors ultimately loose any commitment to their social contacts, a result of their inability to establish any social tie under mutual agreement. Ironically, defectors’ constant search for new partners to exploit leads to heterogeneous networks in which cooper...

• Type: Conference
• Year: 2009
• Where: CEC
• Authors: Sven Van Segbroeck, Francisco C. Santos, Ann Nowé, Jorge M. Pacheco, Tom Lenaerts
• Keywords: Artificial Intelligence, CEC 2009, Long-lasting Relationships, Mutual Agreement, Social Tie