Coevolution of reciprocity and trust

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Thesis Type: Postgraduate

Institution Of The Thesis: Galatasaray University, Sosyal Bilimler Enstitüsü, -, Turkey

Approval Date: 2022

Thesis Language: English

Student: ÖZLEM YAŞAR

Supervisor: Bilge Öztürk Göktuna

Abstract:

This study provides an analytical model to study the co-evolution of trust and trustworthiness in a game-theoretic framework. Trust reflects an agent's belief that other agents cooperate in a two-stage prisoner's dilemma game. Altruist agents receive a utility from their opponents' payoffs, while selfish agents do not consider other players. We also model the third type of agents using Cox et al.'s (2016) concept of vulnerability-responsiveness. A second-mover vulnerability-responsive agent feels responsible for a first-mover agent who cooperated; therefore, she cooperates if her opponent cooperated. However, she does not cooperate if her opponent does not. Then, we use agent-based modelling to test our analytical solutions. We find a very complex relationship between trust and trustworthiness. An increase in trust creates a suitable environment for malicious agents. Hence, a cyclic relationship may emerge.