GIVEN THE TASK OF LEARNING A SERIES OF RANDOMLY ORDERED MEANINGFUL ITEMS, MOST SUBJECTS (SS) IMPOSE SOME ORGANIZATION ON THE MATERIAL DURING THE PROCESS OF LEARNING. AN EXPERIMENTAL PARADIGM IS DESCRIBED WHICH PERMITS THE OBJECTIVE SCORING OF EACH S'S SUBJECTIVE ORGANIZATION OF THE MATERIAL ON EACH LEARNING TRIAL. THE CENTRAL FEATURE OF THE PARADIGM IS THE UTILIZATION OF AN ESSENTIALLY UNSTRUCTURED STUDY SHEET WHICH EACH S PREPARES ANEW, FOR HIS OWN USE, DURING EACH LEARNING TRIAL. NEW INDICES ARE DEVELOPED FOR MEASURING--(1) THE CONSISTENCY OF ORGANIZATION (INDEPENDENT OF SEQUENTIAL ORDER) FROM ONE TRIAL TO THE NEXT, (2) THE STEREOTYPY OF ORGANIZATION ACROSS SS ON ANY ONE TRIAL, AND (3) THE EXTENT TO WHICH SPECIFIC PAIRS OF WORDS ARE TO BE FOUND IN THE SAME SUBJECTIVE CATEGORIES FOR DIFFERENT SS. IN ADDITION TO THE STUDY SHEET PARADIGM, TWO EXPERIMENTS EMPLOYING THAT PARADIGM, AND SEVERAL NEWLY DEVELOPED MEASURES FOR PREVIOUSLY UNMEASURED ASPECTS OF THE SUBJECTIVE ORGANIZATION OF MATERIAL ARE DESCRIBED. A THIRD EXPERIMENT IS CONCERNED WITH A PARTICULAR IMPLICATION OF SUBJECTIVE ORGANIZATION BEHAVIOR. IT WAS FOUND THAT IN A MIXED LIST OF ITEMS, EXHAUSTIVE CATEGORIES ARE LEARNED FASTER THAN ARE EXHAUSTIVE CATEGORIES WITH ONE ITEM MISSING. (AUTHOR/IM)