Joon yong SeoThe College at Brockport (SUNY) attitudes are functional (e.g., Katz, 1960) in that they guide information processing, situational appraisals, decisions, and behavior (e.g., fazio, 1990). our research suggests that familiarity with others' attitudes or "attitude familiarity" is similarly functional. romantically involved partners completed measures of their attitudes and their perceptions of their partners' attitudes, and various measures of relationship quality. Partners who knew each others' likes and dislikes got along better; they reported less conflict and fighting, and were more closely affiliated. They also tended to be more responsive to each others' support needs and upset each other less. These interpersonal processes were generally predicted by attitude familiarity even when the similarity of partners' attitudes was statistically controlled. Hence, attitude familiarity was shown to be a distinct construct from attitude similarity that may be essential to relationship functioning.