摘要:This study examines primary and early childhood pre-service teachers’ strategies on a written task that promotes 3D geometric thinking and visualization processes. Visualization and conceptualisation of 3D objects are complex cognitive processes, and both require the development of students’ abilities to decode and encode spatial information. The analysis of 289 pre-service teachers’ written responses resulted in identifying students’ difficulties in decoding and encoding visual information. The visual information dominated student thinking, and they found it hard to identify relationships between the 2D representation and the 3D mental construction of the solids. Most made incorrect claims regarding relative volumes. Neither spatial visualisation nor formula-driven computation provided adequate engagement with the task. Visualization and conceptualisation of 3D objects are complex cognitive processes, and pre-service teachers need to engage with a variety of learning activities to help them develop their abilities to decode and encode spatial information and, it is hoped, develop their 3D geometric thinking. However, from a learning approach perspective, the results indicate a dominant surface learning approach; this may arise from prior inadequate learning. The best lesson the student may get, therefore, from this task is not the mastery of a mathematical computation, but awareness of the importance of teaching design and aligned teaching methods.