The experiments outlined in this paper assess the relative effectiveness of two approaches to teaching foreign language grammar to adults. One approach, called the "Implicit Method," is based on the audiolingual habit theory of language learning. Grammar is taught inductively through the reading of dialogues and practice with carefully structured pattern drills. The other approach, called the "Explicit Method," is based on the cognitive code-learning theory of language acquisition. Students are given explicit explanations of the grammatical problem before they are given the opportunity to practice the language. The general conclusion drawn from the experiments is that adult students acquire foreign language grammar better by using a cognitive method than by using a method based exclusively on habit-forming principles. Procedures and experimental results are described in this report. (Author/RL)