IT HAS BEEN shown in an earlier study by Fattu, Mech and Kapos (3)* that be havioral rigidity, as measured by the index of behavioral stereotypy proposed by Miller and Frick (6), may be inversely related to problem-solving proficien cy. In that study, 49 adult subjects (graduate students in education) were individually given three sets of six problems each to solve. (The apparatus used was a gear-train. ) After the first set of problems, the se c o nd-ord e r index of stereotypy for good problem-solvers was 0. 29, while that for poor problem-solvers was 0. 36. After the final set of problems, the second-order index of stereotypy for good problem-solvers was 0. 22, while that for initially poor problem-solvers whose performance had improved was 0. 27, and that for consistently poor problem-solvers was 0. 32. Over the full sequence of 18 problems, the index for good problem-solvers was 0. 245; for initially poor but improved problem-solvers, 0. 281; and for consistently poor problem-solvers, 0.345. Behavioral rigidity being thus inversely related to problem-solving pro ficiency in graduate students, how is it related to generally accepted predictors of academic success? The present paper is intended to describe the methods and results of two limited exploratory studies of this question.