Toward a Theoretical Foundation for Design Sketching: Developing a Comprehensive Model for Understanding and Supporting Sketch Activities to Intervene with Sketch Inhibition

Sketching, as one of the core design skills, requires emphasis and cultivation in higher education. However, the advancement of AI and digital tools, along with individual and social issues, has led to ‘sketch inhibition’ - students’ reluctance to use sketches, hindering the acquisition of core design skills. This study develops a comprehensive model to enhance understanding of sketching's role in design processes. We integrate existing sketch taxonomies, which provide validated frameworks for classifying sketching behaviors, with the Uncertainty-Driven Action (UDA) model, selected for its unique capability to link internal cognition with external behavior through uncertainty perception. Following systems theory, we employed multiple complementary methods: literature analysis established theoretical foundations, prototype development created initial frameworks, scenario analysis tested theoretical predictions, natural observation of 21 design students validated real-world applications, and quantitative analysis examined uncertainty management patterns. Results: revealed significant correlations between uncertainty levels and sketching behavior, with peak relationships during exploration stages. The study provides both theoretical foundations and empirical evidence for understanding how designers naturally employ sketching to manage uncertainty in the design process, offering valuable insights for addressing sketch inhibition in design education.