Constructivism and social constructivism view learning as an active process where learners construct knowledge based on their prior knowledge and experiences as well as social and cultural influences. Key theorists include Piaget, who saw learning occurring through assimilation and accommodation, Bruner who emphasized discovery learning, and Vygotsky who highlighted the role of social and cultural contexts. Instruction based on these theories uses discovery learning, collaborative learning, individual exploration tools, and collaborative tools to facilitate student-directed learning.