In the context of developing mentor teachers' use of supervisory skills, two consecutive studies were conducted, using stimulated recall. Firstly, with eight participants, an instrument was developed to categorize contents of interactive cognitions. Secondly, with 30 participants, the instrument was applied to uncover contents of mentor teachers' interactive cognitions, before and after training in supervisory skills. After training, mentor teachers demonstrate an increased awareness of their use of supervisory skills. This indicates that mentor teachers not only seem to emphasize pupil learning and needs when conducting a mentoring dialogue, but simultaneously focus on their own supervisory behaviour. (Contains 3 tables and 1 figure.)