Minicourse 1, a short microteaching program designed to change 12 specific classroom behaviors involved in conducting a discussion lesson, relies heavily on filmed illustrations by model teachers and provides feedback through carefully structured teacher self-evaluation of televised lesson replays. A study was designed (1) to estimate the degree to which practice in the microteaching format and feedback from the video tape replay influenced learning in the minicourse model and (2) to determine the effectiveness of the minicourse as a technique for changing the behavior of student teachers. Five groups of 15 to 17 student teachers from three teacher training institutions were subjects of the study. No variables appeared to influence their assignment to groups: three groups completed the entire minicourse, one was given all but the video tape recordings and replay, and one did no microteaching and received no feedback. Behavior change was measured by trained raters who scored coded 16-minute pre- and postcourse video tapes of each student teaching his entire class. The three research hypotheses were tested using a one-tailed t-test; all three were supported. In general, the groups that completed the entire minicourse made more and larger changes in behavior than the others; and several significant changes occurred in the methods of conducting discussion lessons. (SP 001 962 is a related document.) (JS)