Abstract

Inoculation on attitude is a phenomenon that people resist strong persuasive attacks, through forming an 'antibody' in his own attitude, if he would be frequently exposed to the information to threat his own attitude. However. Characteristics of the antibody has not been discovered. This study was designed on the assumption that attitudinal inoculation results from the change of attitudinal structure, that is change, from bipolarity to duality structure. We suppose that inoculation treatments make people concieve two opponent attitude-objects, 'teeth-brushing' vs 'non-teeth-brushing', from exclusively existing each other(bipolarity structure) to simultaneously standing together(duality structure). Because two opponent attitudes in the duality structure are determined independently, attitude toward 'non-teeth brushing' is changed according to the direction of persuasive attack with 'non-teeth brushing' but attitude toward 'teeth-brushing' is not changed. Those assumptions were supported by two experiments.