Constructivism is derived from the field of cognitive psychology. Facts become facts because it is knowledge that is agreed upon by communities of learners. The learner comes into any new situation with prior knowledge based on past experiences. New knowledge is learned through integration with prior knowledge. Learning is a constructive activity that students have to carry out.
Students are active learners.
Reflection of both content and the learning process is paramount. Conceptual understanding is influenced by the prior knowledge brought by students to learning situations. The teacher can use a map as a basis for which to challenge student assumptions of how concepts are related. What's more important is that students take away major themes or concepts and an understanding of how these concepts are related. Using a concept map to design a course can aid the teacher in guiding the students to learn relevant concepts rather than trivial facts.