Many theorists have examined the roles that social comparison, social projection, and group membership might play in shaping a person's beliefs. Several hypotheses regarding certainty of opinion and perceived similarity between oneself and one's ingroup were tested in a sample of 76 white male commuter students at two universities. Subjects were randomly assigned to one of four experimental conditions and were given packets of questionnaires to complete. Salience was manipulated by either establishing high salience of group identity (conflict induction condition) or maintaining low salience of group identity (interpolated condition). The projection manipulation consisted of either asking students to estimate the attitudes of a target ingroup or omitting this request. The results showed that increasing the salience of ingroup identity by conflict induction did not increase subjects' certainty about their own attitudes, and only in the conflict-related issues did opportunity to project seem to lead to increased certainty. The hypothesis that increased salience of ingroup identity should increase perceptions of similarity between oneself and one's ingroup was clearly supported by the results. Futhermore, within the context of both greater elevation and content similarity, when saliency of group identity was high, subjects perceived themselves to be more similar in elevation to their ingroup on the high-importance and conflict-related issues, while they responded most differently to the content for themselves and ingroup on those same issues. (Descriptions of two pilot studies and the questionnaire forms are included in the appendices.) (NRB)