Adolescents' relationships to siblings and mothers: a multivariate genetic analysis

Research has consistently demonstrated that children's behavior toward their siblings tends to resemble interactions occurring in the parent-child relationship. This study examined the relative contributions of genetic and environmental influences to the covariation between sibling relationships and mother-adolescent relationships. Reported and observed family interactions were assessed for 719 same-sex sibling pairs of varying degrees of genetic relatedness. The covariance between mother-adolescent and sibling interactions was decomposed into genetic, shared, and nonshared environmental components. The overlapping effects of shared environment on the two relationship subsystems explained most of the covariance. Smaller but significant genetic and nonshared environmental effects were also found. The consistency of these findings with family processes, such as modeling, is discussed.

The importance of shared environmental influences in explaining the overlap between mother's parenting and sibling relationships: reply to Neale (1999)

This article addresses concerns raised by M. C. Neale (1999) in his commentary on the D. A. Bussell et al. (1999) Nonshared Environment in Adolescent Development (NEAD) study. These concerns fall into two categories: (a) model assumptions and sample design and (b) testing of alternative models. The validity of the assumptions of quantitative genetic models is a concern for all researchers in this area. Discussion of those assumptions in this reply is brief and focuses on those most relevant to the NEAD sample. The two alternative models proposed by Neale were designed to provide alternatives to the large shared environmental effect found in the original report of Bussell et al. Because these alternative models did not provide a better fit, the appropriateness of Bussell et al.'s basic model and the importance of shared environmental influences for explaining the association among family subsystems are supported.

Genetic questions for environmental studies. Differential parenting and psychopathology in adolescence

BACKGROUND

Recent genetic evidence suggests that the most important environmental influences on normal and pathologic development are those that are not shared by siblings in the same family. We sought to determine the relationship between differences in parenting styles and depressive symptoms and antisocial behavior in adolescence, and to compare the influence of these nonshared experiences with genetic influences.

METHODS

We studied 708 families with at least two same-sexed adolescent siblings who were monozygotic twins (93 families), dizygotic twins (99 families), ordinary siblings (95 families), full siblings in step families (181 families), half siblings in step families (110 families), and genetically unrelated siblings in step families (130 families). Data on parenting style were collected by questionnaire and by video recording of interaction between parents and children.

RESULTS

Almost 60% of variance in adolescent antisocial behavior and 37% of variance in depressive symptoms could be accounted for by conflictual and negative parental behavior directed specifically at the adolescent. In contrast, when a parent directed harsh, aggressive, explosive, and inconsistent parenting toward the sibling, we found less psychopathologic outcome in the adolescent.

CONCLUSIONS

Parenting behavior directed specifically at each child in the family is a major correlate of symptoms in adolescents. Furthermore, harsh parental behavior directed at a sibling may have protective effects for adolescents, a phenomenon we call the "siblin barricade."

Debriefing the family: is research an intervention?

The primary focus of this article is to examine the general assumption that families are left largely unchanged by their participation in research, and to question whether family research can have unintended positive or negative effects on participants. The present article reports feedback from families participating in the Nonshared Environment and Adolescent Development project, a longitudinal study of family process and adolescent development. Families differed in their perceptions about whether the research experience was positive, detrimental, or inconsequential. This feedback underscores the researcher's ethical responsibility to detect and remove deleterious effects of participation. Suggestions are made for providing adequate debriefing to subjects and for using debriefing as a research tool to study the interaction between researcher and families.

Ethical issues in observational family research

Ethical issues raised by the increasing reliance on observational technology in family research are discussed. The tensions between scientific advancement and participant welfare are highlighted by delineating the process of observational research and the nature of the relationship between family scientists and the families they study. Guidelines are proposed for ethical decision making regarding potential child abuse, suicidality, informed consent, confidentiality, and debriefing.