Unlike traditional methods, the communicative approaches draw on implicit and incidental ways of learning and contextualised exercises of grammar which improve language performance in terms of fluency and communicative competence. However, the discursive plan implies the use of high-level units of knowledge and the automatization of low-level knowledge is not ensured. Although learners' production achieves success in terms of communicative skills, their competence in terms of accuracy is usually unsatisfactory. The benefits of explicit grammar teaching are another issue that concerns teachers and that needs more evidence. Therefore, a need exists to study which approach supports the automatization of low-level information, in a short class time (30-40 min). The first purpose of this study is to better understand the cognitive processes that lead to the automatization of forms, the second purpose is to know whether explicit grammar teaching promotes the automatization of forms. When first reviewing the literature on cognitive psychology and automatization, the focus was limited to how automaticity is brought about. Next, the main assumptions of Adaptative Control of Though (ACT*) and Instance Theories are presented. The reviewed research results confirmed the effectiveness of the explicit teaching of rules and the importance of practice and attention in the language learning process. In the conclusion, there are some recommendations that may be useful for language teachers.