TO TEST THE EFFECT OF VIDEO TAPED SIMULATED INSTRUCTIONAL SEQUENCES ON THE MODIFICATION OF TEACHERS' PROFESSIONAL KNOWLEDGE AND ATTITUDES, THREE GROUPS OF PROSPECTIVE TEACHERS WERE DIFFERENTIALLY EXPOSED TO SPECIALLY PREPARED TAPES ON FOUR TOPICS. EACH 30-MINUTE TAPE CONSISTED OF SIMULATED CLASSROOM SETTINGS, WITH THE LAST 10 MINUTES USED AS A POST-TEST IN WHICH THE VIEWER HAD TO IDENTIFY THE PRINCIPLES UNDER DISCUSSION. GROUP 1 RECEIVED NO RELEVANT INSTRUCTION ON THE TOPICS, GROUP 2 RECEIVED ONLY MODEST WRITTEN OR AUDIO TAPED INSTRUCTION, WHILE GROUP 3 WAS EXPOSED TO THE WRITTEN OR AUDIO TAPED MATERIAL PLUS THE VIDEO TAPES. ALL THREE GROUPS WERE GIVEN EACH OF THREE POST-TESTS CONCERNING THE PRINCIPLES OF THE FOUR INSTRUCTIONAL TOPICS--(1) THE VIDEO TAPE POST-TEST SEGMENT, (2) A LOCAL WRITTEN TEST, AND (3) THE INSTRUCTIONAL PROCEDURES PREFERENCE INVENTORY, WHICH MEASURES ATTITUDES TOWARD INSTRUCTIONAL PRINCIPLES. WITH RESPECT TO THE VIDEO TAPE POST-TEST, SIGNIFICANT DIFFERENCES WERE FOUND AMONG THE THREE GROUPS ON ALL FOUR TOPICS (THE NO-INSTRUCTION CONTROL GROUP SCORING LOWEST, AND THE VIDEO TAPE GROUP HIGHEST), BUT, ON THE OTHER MEASURES, THE USE OF THE VIDEO TAPE PROGRAM YIELDED NO SIGNIFICANT DIFFERENCES. FURTHER RESEARCH IS NECESSARY TO LEARN WHETHER THE OBTAINED DIFFERENCES ARE REFLECTED IN ACTUAL TEACHING PERFORMANCE. (LC)