Authors of this paper draw attention to the importance of developing critical thinking in the process of education. For this
purpose, we organized a research (an experiment with parallel groups) on a sample (N=246) of third-grade students of primary
school, to examine if critical thinking can be developed by a better planned selection of content. The obtained results show that
the selection of content can encourage and develop critical thinking of all students, and that there should be no restrictions
regarding the classification of students by their overall performance at school.