Abstract for: Behavioral Drivers of Supply Chain Instability: Exploring the Roles of Supply Line Underweighting and Trust

Supply chain instabilities, such as inventory oscillations and demand amplifications, are influenced by behavioral factors, particularly the misperception of delayed feedback. Supply line underweighting is identified as a significant driver of the bullwhip effect. Decision-making in supply chains involves ongoing relationships where trust in upstream partners is continually reassessed. However, current behavioral models fail to integrate supply line underweighting and trust into a cohesive framework. This study develops a system dynamics model that integrates both behavioral mechanisms within a single framework. The model represents a dyadic supplier-customer relationship in which supply line underweighting affects stock management decisions. Trust evolves endogenously through feedback from delivery performance and reliability, influencing lead time perception of the downstream partner. Simulation experiments based on canonical Beer game conditions are conducted to analyze the system's behavior under various policy assumptions. The results reveal a clear behavioral hierarchy in the drivers of supply chain instability. Supply line underweighting emerges as the dominant mechanism generating substantial amplification in orders and inventory fluctuations when misperceptions are severe. In contrast, trust and expectation-based policies primarily influence the magnitude of fluctuations but do not fundamentally alter system dynamics within our focus range. The findings suggest that cognitive misperception of pipeline inventory plays a more critical role in driving instability than relational trust dynamics within the examined parameter range. While trust shapes perception, its influence is secondary to SLU in determining system behavior. This highlights the importance of improving decision-makers’ representation of supply line information and provides a basis for further exploration of behavioral interactions in supply chains. Editing for clarity and grammar improvement