Optimal User Control Elements When Encountering Errors in Self-Checkout Scenario

In recent years, Japanese retailers have accelerated the adoption of self-checkout systems to address labor shortages, yet approximately 30% of users express anxiety about system errors. Particularly, the “instruction inconsistency state”—where errors occur despite following instructions—inhibits users' sense of self-efficacy and becomes a factor causing significant psychological burden. This study focuses on the “sense of control”—the feeling that users are leading the operation—and aims to clarify what information presentation designs suppress stress during error notification scenarios. Based on prior research, five design factors were extracted, and an experimental model was constructed. An evaluation experiment was conducted using 16 types of UI designs, and the influence of each factor was verified through multiple regression analysis. The analysis revealed that “Flow Visualization” is the most dominant factor in enhancing the sense of control. Furthermore, it was demonstrated that visualization of flow significantly reduces user stress levels, either through the mediating effect of the sense of control or directly.