In recent years there has been a renewal of interest in the possibility of establishing links between conditionability and personality variables. This research is concerned with dual nature of Extraversion-introversion and its relation to neuroticism, and aims to clarify the personality variables which have relations to experimental indices in learning or performance. Seventy items and 9 reference scales, including Si, Pt of MMPI, Guilford's R, etc, were elaborated from the results of other investigations of many important personality scales. And the matrix of 79 variables, 120 samples was factor-analyzed by the centroid method and rotated by the Varimax method. Among obtained 11 factors, three factors were discussed. They were named Social extraversion, Impulsiveness, and Neuroticism factor. In these three dimensional factor space, reference scales were plotted, and the natures of dimensions and the reference scales were interpreted. Three scales were constructed and their interrelations were estimated. Between Social extraversion and Impulsiveness, and between Social extraversion and Neuroticism, there were no correlations. But there was a low correlation between Impulsiveness and Neuroticism. The relationship between these personality dimensions and experimental indices weas discussed. Social extraversion was related to the overall performance level in the massed practice. Impulsiveness was related to variability of performance. Neuroticism had not any significantly related indices. From these results, obtained dimensions were considered to have a high utility for understanding the links between learning and personality variables.