Some view development as continuous: accumulation-> builds on top of earlier experience, no abrupt changes. Some view development as stages; periods of change. Sleeper effect: cope well at first but then show problems with development. Structural-organismic: describe psychological structures and processes that undergo qualitative or stagelike changes over the course of development. Psychodynamic: freud; development occurs in discrete stages and is determined largely by biologically based driven. Id: person"s instinct, first component of personality to evolve, pleasure. Psychosocial theory: erikson; children developing largely through accomplishing tasks that require social interaction. Piaget: development is a biologically organized process; uses principle of adaptation. Behaviourism: theories of psychology must be based on observations of behaviours. Cognitive social learning: stresses the importance of observation and imitation in the acquisition of new behaviors, with learning mediated by cognitive processes. Children imitate behavior: hitting the doll when watching an adult hitting the doll.