A new cognitive intervention strategy was developed to improve teaching and learning in the workplace within the context of Germany's standard system of vocational training, a dual system of theoretical learning at school and practical learning in the workplace. The intervention was based on two elements: training apprentices to learn and work autonomously and training masters to support and promote autonomy. The cognitive development intervention was used with 62 apprentices and 37 masters working in 6 different occupations at 9 companies. The apprentices participated in training sessions and discussions on the following topics: planning strategies, social and communicative competencies, and learning by using multiple sources. The masters participated in training and discussions on the following topics: motivating for autonomy, multilevel teaching, planning work with apprentices, and supporting apprentices' self-evaluation and self-control. A pretest/posttest system was developed to evaluate the intervention's effectiveness. Changes in the apprentices' attitudes toward responsibility were evident even before the evaluation's completion. (MN)