The relation between experimental psychology and second language acquisition research hasgone through at least two major swings of the pendulum. During the heyday of behaviorism, thependulum swung strongly toward psychology. The behaviorist psychologists advised us to thinkof language learning as nothing more than habit formation (Mowrer, 1960), and second languagelearning materials reflected an emphasis on repetition, drill, rewards, practice, and conditioning.During the early years of the cognitive revolution, Chomsky (1959) argued that viewing languageas a conditioned response (Skinner, 1957) ignores the complexities of both language structureand cognition. Persuaded by these arguments, second language researchers turned away frombehaviorist psychology and sought the explanation for language acquisition in universals oflanguage structure (Dulay & Burt, 1974).