Constructivism holds that students learn best through active participation and constructing their own understanding. Key theorists who contributed to constructivism include Piaget, Bruner, Vygotsky, and Dewey. Piaget identified four stages of cognitive development in children. Bruner believed learning is an active process where students construct new ideas based on prior knowledge through exploration. Vygotsky emphasized social development influences learning. Dewey advocated for child-centered, experiential learning activities relevant to students.