Disclosure, or revealing personal information to others, is important for the development and maintenance of close relationships (Jourard, 1971; Rotenberg, 1995). More recently within developmental psychology, however, the focus has been the study of adolescent disclosure to parents as a means of information management regarding their daily activities. This research assumes that a) disclosure between multiple adolescents and parents within the same family are similar, and b) only information transmitted from adolescents to parents is important for adolescent well-being. Thus, this article presents the findings of 2 within-family studies to investigate differences in the amount and social domain (Smetana, 2006; Turiel, 2002) of youth disclosure to mothers versus siblings, and the influence of disclosure to siblings on relationship quality and youth emotional adjustment. Study 1 utilized 101 sibling dyads with youth ranging in age from 11-21 years, but all siblings living together. Study 2 investigated a sample of 58 sibling dyads in which all first-borns were first-year college students and all second-borns were in high school. All participants completed questionnaire measures to assess study variables. Findings revealed that while youth disclosed more to mothers than siblings, this difference disappears by emerging adulthood, particularly depending on the domain of the issue. Additionally, while greater disclosure among siblings was positive for the quality of the relationship, sibling disclosure was differentially associated with emotional adjustment depending on whether youth were the disclosers or being disclosed to, the domain of the issues disclosed, and the gender composition of the dyad.

Siblings are influential on one another’s romantic relationships and sexual behaviors, and examining mechanisms of this influence is important. Using a sample of 62 sister dyads, we examined the content of sisters’ messages about dating and sexuality and correlates of these messages. Sisters shared messages with one another about dating logistics, dating partners, sex, and the importance of self. Using actor–partner interdependence models, we examined how both dyad members’ romantic relationship status and sexual experiences, intentions, and attitudes were associated with sisters’ messages. We found sisters’ experiences—especially older sisters’ experiences—were associated with the content of messages. Consistent with symbolic interactionism, the findings point to the importance of examining sibling communication about dating and sexuality as an important socialization mechanism through which sisters may influence one another’s romantic relationships and sexuality development.

Discrepancies in first- (M = 14.97 years, SD = 1.82) and second-born adolescents’ (M = 12.20 years, SD = 1.90 years) and their parents’ perceptions of parental authority legitimacy (PAL) were examined in a longitudinal sample of 145 predominantly White, middle-class, U.S. families. Utilizing a growth curve modeling approach, changes in the discrepancies between parents’ and both first- and second-born adolescents’ ratings of PAL over the course of 4 years were examined separately by the social–cognitive domain of the issues (social domain theory; Smetana, 2011; Turiel, 2002). We found that discrepancies between parents and first-borns increased over time for personal and multifaceted issues, whereas discrepancies for second-born adolescents increased over socially regulated issues. Additionally, larger initial discrepancies between parents and both adolescents over socially regulated issues (i.e., moral and conventional) were associated with greater depressive symptoms, while decreases in discrepancies over time were generally associated with better adjustment outcomes but with some domain and birth order differentiation. Discussion focuses on the developmental appropriateness (or inappropriateness) of family member perception differences in authority legitimacy over the course of adolescence.

Given the uniqueness of siblings, it is important to consider the presence and role of relational aggression within the sibling relationship. Due to the time spent together and the information disclosed between siblings, during conflict, such information could be used in threatening or relationally aggressive ways. Relationally aggressive actions do not pose a threat to end the sibling relationship, making it a safe relationship to practice such strategies. While parents are likely to be aware of physical aggression between siblings, and attempt to stop it, relational aggression may be difficult for parents to catch and address, reinforcing its effectiveness as a strategy of control. This chapter describes the developmental course of relational aggression within the sibling relationship, as well as associations between relational aggression in the sibling relationship and relationships with others. Finally, we highlight the conclusions and limitations of this research and offer ideas for future research directions.

Adolescents disclose information about romantic relationships and sexuality to family members and friends, but little is known about the correlates of this disclosure. We examined adolescent girls' (N = 68; 34 sister dyads) choice of disclosure partner regarding thoughts/concerns about dating and sexuality. Adolescents were more likely to choose mothers and sisters (compared with friends) as disclosure partners regarding dating and sexuality topics. Using multilevel modeling, we also examined romantic relationship and sexual correlates of disclosure partner selection. Adolescents' disclosure to mothers and sisters was associated with positive relationships. We also found that adolescents who selected mothers as disclosure partners for sexuality reported greater romantic relationship intimacy and adolescents who selected friends as disclosure partners for sexuality reported less conservative sexual attitudes than other adolescents. Furthermore, our findings revealed that adolescents' choice of disclosure partner was associated with their sexual attitudes, and these associations differed by topic and sibling status.