In 1962, a “Human Relationships and Teaching Laboratory” was developed in Chile, in order to induce teachers to think about their teaching activities with consequent attitude changes in teaching-learning process.
Since 1968, several laboratories were performed in our University, including 200 teachers of biological area. Eight teachers were submitted to a questionnaire before the laboratory (pretest), immediately after the same (immediate postest), and three years later (remote postest) in order to evaluate attitude changes. Teachers' opinions were registred according with a Likert scale for 35 propositions. Statistical analysis showed significant differences only between the pretest and both the postest (immediate and remote), but not between postest immediate and postest remote. These results suggest that laboratory induce attitude changes in the participants and these changes remain for at least three years.