The Relationship Code: Deciphering Genetic and Social Influences on Adolescent Development (review)

The Relationship Code: Deciphering Genetic and Social Influences on Adolescent Development. By David Reiss with Jenae M. Neiderhiser, E. Mavis Hetherington, and Robert Plomin. Cambridge: Harvard Univ. Press, 2000. Pp. 532. $55.

Behavioral scientists interested in human development tend to be divided into those whose research focuses either on the role of genetics or the role of the social environment, even though most pay lip service to the importance of both. Members of these camps use different professional jargon, different types of samples, different statistical techniques, and often ignore or speak past one another (although periodic border disputes do arise).

The Relationship Code, by David Reiss and colleagues, is extremely important because it has the potential to revolutionize how both genetically oriented and environmentally oriented behavioral scientists view the process of human development. It calls for a fundamental reconsideration of how cause and effect in human development are viewed.

The Relationship Code operates simultaneously at two levels. At one level, it reports the key findings from a large study of genetic and environmental influences on adolescent development. The study, unique in its size and scope, involved collection of data from families in which siblings had different degrees of genetic relatedness and environmental contact: monozygotic twins, dizygotic twins, full siblings living with both biological parents, full stepsiblings (two full siblings living with one biological parent and one unrelated stepparent), half stepsiblings (who share one biological parent in common but not the other), and unrelated stepsiblings (children living in a stepfamily, each being related to only one of their stepparents). This innovative design, coupled with sophisticated multivariate analyses that examine overall patterns in the data set as a whole, affords a much more comprehensive view of genetic and environmental influences than exists to date in the field.

The study involved 720 families sampled from 47 of the 50 states in the United States. Each family included two parents and two children; the two children represented one of the six forms of relatedness mentioned above. Great care was paid to issues of sampling, selection of measures, data collection procedures, data reduction, analysis, and interpretation. For example, over 675,000 families were screened as possible participants using random digit dialing. In addition, the study was longitudinal, re-visiting families after an interval of three years.

The adolescent outcomes selected for investigation include the most important constructs currently being discussed in the field: antisocial behavior, depressive symptoms, cognitive agency, sociability, autonomy, social responsibility, and self-worth. Parental variables were likewise chosen for their importance in the field: conflict/negativity, warmth/support, monitoring, attempts to control, and actual control. Data were collected from the adolescents, their parents, and trained observers. The book includes readable yet thorough discussions of the method and the research team's decisions that went into its formulation. Detailed data tables and a helpful glossary are included in the appendix. The study stands as an inspiration to those seeking to answer the most complex questions with the highest quality research.

The second level at which the book may be read explicates the investigators' process of scientific inquiry. Reiss and colleagues invite the reader to join them as they outline the scientific mysteries standing in the way of understanding human development, muse about alternatives and how one would go about exploring them, muster evidence favoring or contradicting different hypotheses, and draw conclusions. The authors encourage the reader to set preconceived ideas aside, arguing that the data (rather than political agendas, disciplinary proclivities, or methodological traditions) should guide the scientific process. Throughout the book, the authors remained open to alternative explanations and carefully outlined the patterns of data that would support or refute each. In many cases, the research team had the data necessary to allow clear inferences to be drawn. But when the data were not available, the authors were entirely forthcoming, encouraging the reader to stay open to remaining possibilities and...