Integrating emotion and expectation improves cooperation

Cooperation is a key issue attracting widespread attention across various fields. Emotions and expectations jointly participate in the decision-making process, and are key factors influencing the evolution of cooperation. Therefore, this paper proposes a game evolution model that considers the dual influences of emotions and expectations. In the model, a player’s initial strategy depends on their emotions. Subsequently, expectations influence the decision-making process, altering the player’s initial strategy to the current strategy. Specifically, high expectations lead players to maintain their initial strategy, whereas low expectations prompt them to change strategies. Furthermore, the paper analyzes the evolution of cooperation in the prisoner’s dilemma and the influence of expectations. Simulation results show that under high betrayal temptation, players with loneliness and defection would change their initial strategy to cooperation due to low expectations, while those players who initially gather with cooperation strategies maintain the cooperation strategies due to higher expectations, ultimately increasing the cooperation fraction and payoff of the population. Therefore, expectations effectively enhance the cooperation level and payoff of the population. When the scale of individuals changing their strategies based on expectations (ICSE) is large, the effect of expectations on enhancing cooperation and payoff is more pronounced. Frequent consideration of anticipated initial strategy changes also yields the same effect. Additionally, mechanisms of the influence of emotion on payoff, direct emotion interaction and the influence of strategy on emotion collectively contribute to enhancing the significantly evolutionary advantage of friendly emotions and cooperation strategies. This paper contributes to a deeper understanding of the role of expectations in the evolution of emotions and cooperation, laying the groundwork for enhancing social cooperation through expectation management.