The ecological model of human development was appealing and very quickly was accepted as a useful framework within which to study development; it was taken up by psychologists, sociologists and teachers. It began to feature in textbooks and the idea of the nested systems seems to have provided a very useful visual guide accounting for the myriad factors that affect development. Within the bioecological model Bronfenbrenner highlighted the development of the individual within context and also drew a critical distinction between ‘environment’ and ‘process', with process occupying a central, driving position in development and having a meaning that is quite specific to the model. Active behavioural dispositions are related to variations in motivation, persistence and temperament. Bronfenbrenner notes that even when children have equivalent access to resources, their developmental courses may differ as a function of characteristics such as the drive to succeed or the persistence in the face of hardship.