Across a lifetime

Building and pruning.

Growth and pruning

Connections are overproduced early and pruned by use. Development continues into the mid twenties, with the prefrontal areas involved in planning and inhibition maturing last.

Adolescent risk-taking has a developmental basis and is not simply poor character.
Aging brings gradual change, and dementia is a disease rather than normal aging.

Protective factors

Physical exercise has the best evidence for maintaining cognition with age. Education, social contact, sleep and vascular health also matter.