This study examined the effects of family communication environment and parental mediation of television content on third-, sixth-, and ninth-graders' perceptions of realism and similarity of television content and identification with television characters. Subjects, 627 northern California students and 486 of their parents, responded to episodes of "The Cosby Show." Prior to viewing one of three episodes, students completed a questionnaire assessing general background variables, leisure time activities, media use patterns, and family communication patterns. Immediately after viewing, children completed posttest questionnaires. Parents were interviewed via telephone. Active family communication emerged as an important influence, through both direct and indirect paths. Results indicated that family communication helps form children's real-world perceptions, which they compare with television perceptions to assess realism. Results indicated that a mismatch between real-world and television-world perceptions diminishes perceptions of realism and that realism contributes to perceived similarity, which contributes to identification with television characters. Results also showed that through active discussion of television content, the parent directly mediates perceptions of similarity, but not of realism. (Two figures and five tables of data are included. Twenty references are attached.) (MG)