continuity principle
survivorship principle
individuality matters
normal aging is different from disease
young-old
old-old
oldest-old
centenarians
super-centenarians
normative age-graded
normative history-graded
non-normative
environments are not random
genes influence our exposure to certain environments
genes influence our experience of certain environments
passive
evocative
active
individual
microsystem
mesosystem
exosystem
macrosystem
chronosystem