[Development of the Japanese Optimism and Pessimism Scale: reliability and validity].

This study reports about the construction of a bidimensional measure of optimism and pessimism (defined as positive and negative outcome expectancies), called the Japanese Optimism and Pessimism Scale (J-OPS), and examines its reliability and validity. The participants were college students. The results revealed the following: (a) the J-OPS had sufficient reliability and validity, (b) optimism and pessimism were bidimensional in structure, (c) the general pattern of correlations with external criteria of psychological well-being (positive and negative affectivity). After controlling for optimism and pessimism respectively, it indicated that these two constructs were partially independent of each other. Namely, optimism, but not pessimism, was found to be a consistent predictor of positive affectivity (psychological well-being), whereas pessimism, but not optimism, was found to be a predictor of negative affectivity (psychological distress).