Theoretical Questions and Properties

Theoretical perspectives on development derive from a wide variety of viewpoints.
Although there are numerous important theoretical issues in development,
three questions are central for most theories. The first of these is
the so-called nature-nurture question, concerning whether most behavioral
development derives from genetics or from the environment. The second of
these issues is the role of children in their own development: Are children
active contributors to their own development, or do they simply and passively
react to the stimuli they encounter? Finally, there is the question of
whether development is continuous or discontinuous: Does development
proceed by a smooth accretion of knowledge and skills, or by stepwise, discrete
developmental stages? Current perspectives within developmental psychology
represent very different views on these issues.
Useful developmental theories must possess three properties. They must
be parsimonious, or as simple as possible to fit the available facts. They must
be heuristically useful, generating new research and new knowledge. Finally,
they must be falsifiable, or testable: A theory that cannot be tested can never
be shown to be right or wrong. Developmental theories can be evaluated in
terms of these three criteria.