Does Removing Pen Pressure in Cost-Cutting Pen Designs Matter for Handwritten Learning in Education? A Case Study of Geometry Problem Solving

Digital handwriting is increasingly used in educational settings; however, many classroom styluses omit pen pressure sensitivity due to cost and procurement constraints. While prior work has shown that pen pressure supports written arithmetic, its role in other learning activities remains insufficiently understood. In this study, we investigate how pen pressure–based stroke modulation affects problem-solving performance in digital handwriting, using geometry problems as a case study. We conducted a between-subjects experiment comparing pressure-sensitive and non-pressure-sensitive conditions in tasks requiring spatial reasoning and iterative diagram construction. Although overall accuracy did not differ significantly between conditions, detailed analyses revealed that the absence of pen pressure disproportionately affected lower-performing participants and reduced accuracy in unfamiliar or cognitively demanding problems. In solid geometry tasks, the non-pressure-sensitive condition also resulted in longer completion times. Qualitative analyses further showed that pen pressure enabled effective visual organization and depth representation, whereas its absence led participants to adopt compensatory diagramming strategies, such as relocating annotations outside figures. These findings indicate that omitting pen pressure is not a cognitively neutral design decision. Pen pressure functions as a representational resource that supports exploratory reasoning and visual organization in digital handwriting, with important implications for the design of educational input devices and learning environments.