Constructivist teachers engage students in experiences that might engender contradictions to their initial hypotheses and then encourage discussion.
Cognitive growth occurs when an individual revisits and reformulates a current perspective. Therefore, constructivist teachers engage students in experiences that might engender contradictions to students' current hypotheses. They then encourage discussions of hypotheses and perspectives. Contradictions are constructed by learners. Teachers cannot know what will be perceived as a contradiction by students; this is an internal process.