This episode introduces the Dunedin Longitudinal Study, begun in 1972 and continuing today. It then looks at indicators in childhood behaviors identified by the study that can predict whether a person will have a more or a less stable and successful life as an adult. What are the basic indicators?

What happens when young people run off the rails? Based on the Dunedin Longitudinal Study results, this episode examines why most young adolescents engage in juvenile delinquency of some sort, minor and major, and why most of these delinquents desist whereas a few become violent career criminals.

The Dunedin Study has identified a fundamental developmental mechanism that completely rewrites the nature versus nurture argument. It is a genetic switch which is thrown by life events – nature loads the gun but nurture pulls the trigger. This episode tracks the study's hunt for this mechanism.

This episode of the series examines ways in which the results of the Dunedin study have contributed to a new understanding of early influences in a person's life. Family stability, social interactions and even the presence of pets contribute to health and general success in later life.