An Experimental Study Using Simulated Tasks Reflecting Graphic Elements to Reduce Human Error in Plant Maintenance Procedures

Objective: This study investigates whether incorporating graphic elements to support cognition into work procedures can reduce human error and improve task performance in maintenance tasks within Process Safety Management (PSM) workplaces.<br/>Background: Major industrial accidents in aging facilities that handle hazardous chemicals frequently occur during maintenance activities, often due to human error and inadequate work procedures. Despite the importance of cognitively supportive procedures, their development and implementation remain limited.<br/>Method: This study used a LEGO assembly task as a substitute for the actual maintenance task to compare four types of procedures varying in cognitive support: (A) black text only, (B) color text with B/W photos, (C) color text with color photos, and (D) color text with color photos and explanatory notes. Thirty-six participants were randomly assigned to one of four procedure types (n=9 per group). Task completion time and the number of assembly errors were measured as dependent variables.<br/>Results: The results showed a significant reduction in both task completion time and the number of errors as the level of cognitive support increased. Compared to type A procedure, type D led to a 76.5% decrease in task completion time and a complete elimination of errors.<br/>Conclusion: Work procedures must be written in a format that workers can easily comprehend. Incorporating cognitive support elements—such as visual cues and explanatory notes—into procedures enhances understanding and contributes to reducing human errors during task execution.<br/>Application: Although the development of visually enriched procedures requires more time and effort, such investments can help workers better understand the nature of their tasks and ultimately reduce human error in high-risk maintenance environments.