Theory: Richard M. Lerner is the psychologist most associated with this theory. Broad, and lacking any a priori assumptions, it relies on contextual relativism to describe and attribute causation for both individuals and groups thereby explaining the immense diversity observed. Its basis is a life-span developmental model but holds that developmental processes arent unmediated, predetermined, stereotypical or immutable. It positions itself as a compromise between the mechanistic and organismic models of development in that there are dynamic interactions and reciprocal relationships between the components that these other models represent exclusively. The interactions are bi-directional and focus on the changing, developing individual and the ecological context in which they exist. Lerner does recognize epigenesis but believes it to be probable, not universal or invariant.

Basic Components: Lerner uses an elaborate contextual diagram that involves qualitative variables such as historical time period, culture, society, community, family, parent , social network, and biological characteristics and then analyzes interactive patterns. The bi-directional pattern allows for mutual influence and is referred to as dynamic interactionism. Tremendous capacity for change is inherent in the concept. Context is defined as an interactive system of social variables, which also includes the physical surroundings and the individual himself due to his influence on the context. Goodness of fit is the major determinate of a positive or negative outcome. It involves the blend between the highly individualistic epigenic plan and the psychosocial demands placed upon that individual. Plasticity is an essential attribute of the human organism, as individuals are continuously in the process of changing and developing and contextual events actively contribute to this process.

Impact on Adolescent Development: Goodness of fit between adolescent temperament and parental characteristics can generate harmony while poorness of fit can create discord. What matters most is the match between childs attributes and their home, peer group and school context. If the characteristics meet the demands or expectations of significant others then the child would receive supportive and positive feedback from the context and should show evidence of the most adaptive behavioral development.

Positive Effects of Divorce: It may be positive if goodness of fit is improved resulting in more positive interactions with family and especially the custodial parent. This may take the form of increased participation in family decision making or encouragement to generate independent choices. The timing of divorce as a variable has different effects depending upon the age of the child.

Negative Effects of Divorce: Incongruence between the individual and the context can contribute to adolescent problem behavior such as substance abuse, early sexual behavior and delinquency. It typically means the quality and level of supervision are decreased. Other socioeconomic factors come into play such as reduced family income, assets and changes in physical location and characteristics of the home. Remarriage of the custodial parent during the individuals pubescence has been found to be detrimental to development.

How to Create a Positive Outcome: Positive outcomes occur when an individuals personality is congruent with the social context. Goodness of fit produces circumstances that enhance constructive, adaptive development and adjustment. The concept of plasticity creates optimism because the person can change through appropriate, deliberate interventions such as education and therapy. The younger person is usually more malleable than the older one, so the earlier the better. One needs to ask specific questions about relevant variables and the interaction process must be understood before meaningful suggestions for intervention can be generated.