Abstract

This study intended to find out the source of an ingroup favoritism in social categorization. It is hypothesized that the ingroup favoritism occurs because individuals evaluate both the ingroup and outgroup with the criteria of the ingroup values. In order to examine this hypothesis, subjects were allocated to three groups and given a treatment of categorization, decategorization and recategorization respectively. The categorization condition was created by making sexual identity salient. Subjects were manipulated to identify themselves with sexual categories. In this condition, the ingroup favoritism was expected to increase as the individuals judge both the ingroup and outgroup by the criteria of ingroup values. In contrast, the recategorization condition in which the boundary of male and female categories were reset into one-group and the decategorization condition in which the boundary of categories were eliminated are expected to decrease the ingroup favoritism. These hypothesis were confirmed by the given experimental data.