Post-merger integration (PMI) presents a complex strategic challenge, requiring managers to navigate interdependent decisions within bounded rationality constraints. This study integrates cognitive representation into the NK model, examining how cognitive intensity, bias, and experience richness shape both short-term efficiency and long-term learning in PMI. The results indicate that high cognitive intensity can improve short-term efficiency, but may lead to premature convergence and limit long-term adaptability. Cognitive bias can affect decision-making efficiency and be detrimental to long-term performance. Rich experience can stabilize the initial decision, but over time, the effect will gradually weaken. Enterprises must dynamically balance exploration and development strategies. Successful PMI requires an adaptive cognitive framework, in which decision intensity, bias, and experience will continuously evolve throughout the integration process. These insights contribute to strategic management literature by demonstrating the dynamic nature of management cognition in PMI, and provide practical insights for companies seeking to optimize post merger performance.