Constructivism is a branch of cognitivist theory which focuses on the active role of the learner in the process of learning. Early constructivist thinkers and concepts pre-date the cognitive revolution of the 1950s, as John Dewey's notion of experiential education and Frederick Bartlett's schematic account of memory demonstrate. Piaget's key concepts of adaptation and disequilibration had a profound influence on education in the latter half of the twentieth century, and later constructivist notions such as Bruner's scaffolding and Bandura's self-efficacy are relevant to both general learning and second language acquisition research today.