This research investigates the influence of culture on sketching by comparing UK and Chinese designers. We employed a novel dual-method approach: machine learning algorithms analyzed a dataset of 2,090 digitized sketches from student designers, while protocol analysis based on shape transformation rules examined the sketching processes of professional designers from both cultures. The machine learning analysis classified sketches by extracting region- and shape-based features, revealing distinctive visual attributes between the two cultures. Concurrently, protocol studies of professional designers' sketches uncovered patterns in their sketching processes. By integrating computational analyses of student sketches with protocol studies of professional designers, we identified significant cultural differences in both visual attributes and sketching processes. The paper discusses potential factors contributing to these disparities, drawing on insights from cross-cultural comparisons of cognitive styles. This comprehensive mixed-methods analysis provides new insights into the complex interplay between culture, cognition, and design.