The five-factor model of personality traits: An examination based on fuzzy-set theory.

The purpose of the present study was to examine the five-factor model (FFM) of personality traits in the framework of fuzzy-set theory. Four hundred and thirty-eight undergraduates rated themselves (self-ratings) and their parents (other-ratings) on monopolar scales of fifty personality traits. The data were analyzed with factor analysis and Oda's Fuzzy-set concurrent Rating (FCR) method (1993b). Results were as follows: (a) The robustness of FFM was confirmed in both self- and other-rating data. (b) The first three factors of FFM clearly corresponded with the basic dimensions of interpersonal cognition proposed by Hayashi (1978). (c) The degree of contradiction found in self-rating data, based on the analysis with the FCR method, was greater than that of other-rating data. These findings suggest that fuzzy-set theory was effective in its application to the analysis of personality and interpersonal cognition in the framework of the five-factor model.