This study investigated changes in intellectual orientations of 4,124 California high school students who completed the Omnibus Personality Inventory. The three dependent measures of intellectual orientations were Autonomy (which measures independence of thought and judgment), Theoretical Orientation (which reflects an interest in science, problem-solving and logical thinking), and Thinking Introversion (which measures preference for reflective, abstract thinking and academic activities). The statistical model that was fit to the data was a repeated measures model, an analysis-of-variance mixed model with two grouping factors (sex and type of program of the student), and within-subject factor (intellectual orientation measures at grades 9 and 10) as the fixed effects factor. The results of the study showed that students in diverse high school programs (General, College Preparatory and Vocational) in California became more interested in ideas and reflective thought (Thinking Introversion), liberally oriented, more analytical and critical in their approach to problems. The data showed differential change in intellectual orientations for the students in different high school programs, however. (Author/BW)