Caroline Bulf studied some symmetry’s effects on conceptualization of new
mathematical concept at two different levels at French secondary school, with
students who are 12-13 years old and 14-15 y.o. From the study, the concept of
symmetry makes students confused with the transformations of the plan introduced at
the beginning of secondary school. Students seem to be more familiar with metrical
properties relative to the symmetry and develop mathematical reasoning at the end of
secondary school.