THE EMPHASIS IN THIS STUDY WAS ON EXPLORING MEANS OF MAKING PROGRAMS MORE RESPONSIVE TO INDIVIDUAL DIFFERENCES AMONG LEARNERS AND ON DEVELOPING RULES AND PROCEDURES FOR WRITING AND IMPROVING PROGRAMS. THE PROGRAMED COURSE IN BEGINNING SPANISH SELECTED FOR THE STUDY WAS DESIGNED FOR USE BY STUDENTS WITHOUT THE ASSISTANCE OF A TEACHER. IT ATTEMPTS TO TEACH SIMULTANEOUSLY THE FOUR BASIC LANGUAGE SKILLS--LISTENING COMPREHENSION, SPEAKING, READING, AND WRITING. A TOTAL OF APPROXIMATELY 90 SEVENTH-GRADE STUDENTS PARTICIPATED AS SUBJECTS IN THE STUDY. THE ORIGINAL PROGRAM WAS ADMINISTERED AND THEN REVISED INTO FOUR VERSIONS, EACH SUCCESSIVE VERSION INCORPORATING MODIFICATIONS SUGGESTED BY THE LEARNING BEHAVIOR OF THE STUDENTS. THE FINAL PROGRAM VERSION WAS DEVELOPED AFTER TUTORIAL SESSIONS WHICH WERE DEVOTED TO IMPROVING THE BRANCHING PROCEDURES AND THE REMEDIAL EXERCISES. CONCLUSIONS DRAWN FROM THIS STUDY INCLUDED--(1) PROGRAMS CAN AND SHOULD BE MADE MORE RESPONSIVE TO INDIVIDUAL DIFFERENCES IN LEARNERS, (2) THE TEACHER HAS AN IMPORTANT ROLE TO PLAY IN CONNECTION WITH THE USE OF PROGRAMED MATERIALS, (3) EXCESSIVE VARIABILITY IN REQUIRED RESPONSE BEHAVIOR FROM ITEM TO ITEM CAN INTERFERE WITH LEARNING, (4) FOR MOST SEVENTH-GRADE STUDENTS IN THE STUDY, SHORT AND FREQUENT INSTRUCTIONAL SESSIONS ARE BETTER THAN LONG ONES, AND (5) FREQUENT DIAGNOSTIC TESTING IMPROVES LEARNING. (WB)