The history of learning theory moves from behaviorism's observable stimulus-response mappings through cognitivism's information-processing models to constructivism's recognition that knowledge is built, not received. Each paradigm captures something real: conditioning shapes behavior, cognitive architecture constrains processing, and meaning is indeed constructed by the learner from the raw material of experience. No single theory is adequate to the full range of what learning is, and the skilled teacher draws on all of them without being confined by any.
Each step builds on the last.