THE present study is one of a series comparing the relative effectiveness of various pretreatments in making initially unquestioned beliefs resistant to change when subsequently the person is forced to expose himself to strong counterarguments against the belief. The theoretical point of departure of the present and the earlier studies is the postulate of "selective exposure." Initially strong appearing beliefs, it is assumed, are actually quite vulnerable under forced exposure to strong counterarguments, because such beliefs tend previously to have been overprotected. By selective avoidance of counterarguments in the past, the person has kept his beliefs extreme, but has also left himself unpracticed in their defense and unable to deal with strong counterarguments when exposure to them is forced. The postulate of "selective exposure" is no novelty in communication research. Since Klapper (1949) called it "the most basic process thus far established by research on the effects of mass media," it has stimulated much research, designed either to account for it in a theoretical system (Festinger, 1957) or to use it predictively (Janis, 1957). Its general relevance to the present problem is to suggest that beliefs can be "inoculated" against persuasion in subsequent situations involving forced exposure to strong counterarguments by pre-exposing the person to the counterarguments in a weakened form that stimulates—without overcoming—his defenses (Lumsdaine & Janis, 1953). The hypotheses tested in the study reported here were suggested by interpretations of the outcomes of two previous studies. One of them (Papageorgis & McGuire, 1961) demonstrated that prior exposure to refuted counterarguments tends to make a belief more resistant to subsequently presented strong forms, not