THIS PAPER PRESENTED RESULTS FROM AN EXPLORATORY STUDY OF DIFFERENTIATION IN WHICH ADOLESCENTS WERE GIVEN THE TYPICAL DAY INTERVIEW. THE FOCUS OF THE INSTRUMENT WAS ON THE STUDENT'S ABILITY TO COGNITIVELY DIFFERENTIATE ASPECTS OF THE SCHOOL ENVIRONMENT. DIFFERENTIATION WAS DEFINED AS CAPACITY TO PERCEIVE NUANCES OF PROBLEMS, PEOPLE, AND PROGRAMS WHICH COMPOSE ONE'S ENVIRONMENT. EACH OF 30 STUDENTS FROM A PRIVATE SECONDARY SCHOOL WROTE A LOG OF OCCURRENCES FROM RISING UNTIL RETIRING, AND EACH WAS INTERVIEWED FOR ELABORATION. THE DIMENSIONS ON WHICH THE TYPICAL DAY INTERVIEW WAS EVALUATED AND SOME TYPICAL RESPONSES WERE GIVEN. STUDENTS WERE RATED ON ABILITY TO DIFFERENTIATE SCHOOL, PERCEPTION OF TEACHERS, PERCEPTION OF CLASSES, AND INDEPENDENT INITIATIVE. ACTIVITY LEVEL, USE OF FREE TIME, AND RELATIONS WITH PEERS WERE ASSESSED. ROLE OF THE PARENTS IN THE ADOLESCENT'S DAY AND THE ROLE OF THE GYM WERE ALSO RATED. INTELLECTUAL ABILITY BASED ON TESTS AND ACHIEVEMENT BASED ON GRADES WERE TABULATED. THE STATISTICAL STUDY INCLUDED RELIABILITY FINDINGS, COMPARISONS OF BOYS AND GIRLS, COMPARISONS OF TWO ABILITY TRACKS, AND COMPARISONS OF GRADES 7, 9, AND 11. FINDINGS SHOWED DIFFERENTIATION CORRELATING HIGHLY WITH ORGANIZATIONAL ABILITY AND INDIVIDUAL INITIATIVE, AND MODERATELY WITH GRADES AND INTELLECTUAL ABILITY. NO RELATIONSHIPS WERE FOUND BETWEEN DIFFERENTIATION AND ACTIVITY LEVEL, PEER RELATIONS, ROLE OF THE GYM, INCREASES IN AGE AND MATURITY, SEX DIFFERENCES, OR USE OF FREE TIME. FURTHER STUDY WITH STUDENTS FROM URBAN AND SUBURBAN SCHOOLS AND OF WIDER ABILITY RANGES WAS RECOMMENDED. (TC)