THE INVESTIGATION REPRESENTS A LARGE-SCALE, CONTROLLED STUDY OF A WIDE VARIETY OF ADAPTIVE SKILLS AND DEFICITS OF DELINQUENT BOYS (FIRST-TIME INMATES AT THE RHODE ISLAND TRAINING SCHOOL) AS COMPARED WITH MATCHED NONDELINQUENTS. ALL SUBJECTS WERE ADMINISTERED THE HALSTEAD-REITAN NEUROPSYCHOLOGICAL BATTERY FOR ADULTS AND THE WECHSLER ADULT INTELLIGENCE SCALE. SAMPLE MEANS AND STANDARD DEVIATIONS WERE COMPUTED ON ALL TASKS, AND DIFFERENCES BETWEEN PAIRS OF SAMPLE MEANS WERE TESTED STATISTICALLY USING THE T-TEST FOR MATCHED SAMPLES. RESULTS SHOW SIGNIFICANT DIFFERENCES BETWEEN DELINQUENT AND CONTROL GROUPS FOR NEARLY ALL TESTS, AN OVERALL DEARTH OF ADAPTIVE ABILITIES FOR THE DELINQUENTS IN COMPARISON TO THE CONTROLS, AND LESS IMPAIRMENT FOR DELINQUENTS FOR LESS COMPLEX ADAPTIVE ABILITIES. DELINQUENTS SHOW DEFICITS WITH RESPECT TO CONTROLS IN THEIR ABILITY TO COMPREHEND, MANIPULATE, AND USE CONCEPTUAL MATERIALS IN VERBAL FORM, TO ORGANIZE NONVERBAL PERCEPTUAL MATERIAL, AND TO OPERATE EFFECTIVELY ON THE BASIS OF NONVERBAL PERCEPTIONS. A DIFFERENCE WAS DETECTED IN DELINQUENTS' ABILITY TO ORGANIZE SPATIAL PERCEPTIONS, USE CONCEPTS IN ORDER TO GENERATE A CORRECT SEQUENCE OF SPATIAL LOCATIONS, AND TO PERFORM NONVERBAL CONCEPT-FORMATION TASKS. THE DIFFERENCES BETWEEN DELINQUENT AND CONTROL SCORES IN SHORT-TERM MEMORY AND ATTENTION AND TACTUAL PERFORMANCE TESTS WERE LESS WIDE. IT IS CONCLUDED THAT CLINICIANS RECEIVING COURT-REFERRED JUVENILE PATIENTS SHOULD EVALUATE THE CHILDREN'S SENSORY-MOTOR AND PERCEPTUAL SKILLS AND VERBAL AND NONVERBAL CONCEPT FORMATION, AND THAT MORE RESEARCH SHOULD BE DONE INVOLVING SKILL IMPAIRMENTS OF DELINQUENTS. REFERENCES ARE APPENDED. (DAG)