When trying to explain why people develop as they do, scientists usually consider four interactive forces:
- Biological forces comprise all hereditary and health linked factors that influence development.
- Psychological forces comprise all inner perceptual, cognitive, expressive, and behavioral factors that have an effect on development.
- Socio-cultural forces take account of interpersonal, public, intellectual, and cultural factors that have an effect on development.
Each person is a product of a unique combination of these forces. No individuals of two characters, even in one family unit, experience these forces in the same way; even indistinguishable twins ultimately have singular friendship associations, partners, and professions. However, if behavior seen at one point in the life span can be represented or depicted in the same way as behavior at another point, then descriptive continuity exists. If behavior seen at one point in the life span cannot be represented or depicted in the same way as behavior at another point, then descriptive discontinuity exists.
Let us consider, for instance, recreational behavior studied in adolescence and young adulthood. If the same activity was the major form of recreational behavior at both points in the life span, then descriptive continuity would exist.
Changes in the description of behavior across a person’s life can occur for many reasons. If the same explanations are used to account for behavior across a person’s life, then this means that behavior is interpreted as involving unchanging laws or rules. In this case there is explanatory continuity. If, however, different explanations are used to account for behavior across a person’s life, then there is explanatory discontinuity.
Biological Forces of continuity development
Prenatal development, brain maturation, puberty, menopause, facial wrinkling, and change in cardiovascular functioning may occur to an individual as examples of biological forces. Indeed, major aspects of each are determined by the genetic code. For example, many children resemble their parents, which show biological influences on development. But biological forces also include the effects of standard of living factors, such as exercise. Collectively, biological forces can be viewed as providing the raw material necessary and as setting the boundary conditions (in the case of genetics) for development.
People develop in the world, not in a vacuum. To understand human continuous development, we need to know how people and their environments interact and relate to each other. That is, we need to view an individual’s development as part of a much larger system in which no individual part can act without influencing all other aspects of the system. This larger system includes one’s parents, children, and siblings as well as important individuals outside the family, such as friends, teachers, and co-workers. The system also includes institutions that influence development, such as schools, television, and the workplace. At a broader level, the society in which a person grows up plays a key role.
Nevertheless, descriptive qualitative changes involve differences in what exists, in what sort of phenomenon is present. The emergence in adolescence of a drive state never before present in life and the emergence in adolescence of new abstract through capabilities not present in younger people (formal operation) are instances of changes interpreted as arising from qualitative alterations in the person. It is believed that the person is not just “more of the same;” rather the person is seen as having a new quality or characteristic.