Programmed instruction is an approach to teaching in which material is broken into small, carefully sequenced steps (frames), each requiring an active response from the learner, followed by immediate feedback. Originating in B.F. Skinner's behaviourist learning theory (1954), it was applied to language teaching from the 1960s onward and has found its most successful modern expression in app-based language learning, particularly Duolingo.
Skinner's original "teaching machines" were mechanical devices. Computer-Assisted Language Learning (CALL) from the 1960s onward transferred these principles to digital formats. The modern successor is Duolingo (founded 2011), which combines programmed instruction with: