RESEARCH IN THE LEARNING, MOTIVATION, AND PERCEPTION OF MENTAL RETARDATES IS ESSENTIAL TO AN UNDERSTANDING OF THEIR BEHAVIOR AND OF THEIR ABILITIES. MANY INVESTIGATORS HAVE USED THE PROBLEMS AND DESIGNS OF RESEARCH WITH LOWER ANIMALS IN STUDYING THE BEHAVIOR OF HUMAN RETARDATES. IT IS QUESTIONABLE THAT SUCH ORIENTATION WILL REALLY ADD TO THE UNDERSTANDING OF MENTAL RETARDATION. ALSO, RESEARCH WITH THE MENTALLY RETARDED HAS TENDED TO TREAT THE PROCESSES OF LEARNING, MOTIVATION, AND PERCEPTION AS UNRELATED. THIS CAUSES THE RESULTS OF SUCH INVESTIGATIONS TO BE DIFFICULT TO INTERPRET AND RESTRICTED IN VALUE FOR GENERALIZATION. THERE HAVE APPEARED, HOWEVER, ENCOURAGING EXAMPLES OF NEW RESEARCH ON RETARDATION THAT ARE NOT SO NARROW, FRAGMENTARY, AND UNIMAGINATIVE. EXAMPLES OF THIS RESEARCH INCLUDE (1) A SERIES OF STUDIES INVESTIGATING THE RELATIVE SIGNIFICANCE OF CHRONOLOGICAL AGE, MENTAL AGE, AND INTELLIGENCE QUOTIENT FOR LEARNING IN RETARDED INDIVIDUALS, (2) STUDIES REEVALUATING BEHAVIORAL DIFFERENCES IN LEARNING AND PERCEPTION BETWEEN FAMILIAL AND ORGANIC RETARDATES, (3) WORK ON COMPARING THE PERFORMANCE OF INSTITUTIONALIZED AND NONINSTITUTIONALIZED RETARDATES, (4) INVESTIGATIONS OF THE RELATIONSHIP BETWEEN ABILITY TO PERFORM COMPLEX LEARNING TASKS AND ABILITY TO UTILIZE VERBAL CUES, AND (5) STUDIES ON THE EFFECT OF STIMULI FROM THE PHYSICAL ENVIRONMENT ON THE BEHAVIOR OF RETARDED CHILDREN. THIS ARTICLE WAS PUBLISHED IN "EXCEPTIONAL CHILDREN," VOLUME 28, MAY 1962. IT IS A SHORTENED VERSION OF A LONGER PRESENTATION PREPARED BY HAROLD STEVENSON AND EDWARD ZIGLER UNDER THE SPONSORSHIP OF THE COOPERATIVE RESEARCH PROGRAM OF THE OFFICE OF EDUCATION, U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE. (WD)