This paper reports ongoing research, which was started in 2000 and is meant for completion by June 2002. The purpose of the research is to determine, through classroom intervention, whether primary school student's geometric thought develops according to a specific pattern. The research pays particular attention to the possible development that occurs in student's geometric understanding during a six-month intervention program. The study involves the implementation of an instructional program in a grade 6 South African class which covers the prescribed syllabus for that particular grade for the academic year. The research focuses predominantly on the student's reaction to the instruction in a normal classroom setting. The research involves an experimental and control group with pre- and post tests being administered to ascertain whether a shift in students understanding has occurred. A grade 7 class is used as an additional control group to compare and, to some extent, verify the levels of development of students at the beginning and end of an academic year. The research method, in addition, includes the collection of quantitative data by means of a student questionnaire to establish their perceptions of the classroom environment during the intervention. A variety of other data collection methods will be introduced, including observations, interviews with selected students and the subject teacher involved as well as journal writing by students during the intervention.