ABSTRACT
Human cognition develops over a very long period. By the third month of the prenatal period, electrical activity in the fetal brain elicits kicks, toe curls, arm bends, and other activities. By the fifth month of the prenatal period, essentially all neurons are in place. Yet the brain continues developing on a large scale well into adolescence, and smaller changes in response to experience occur throughout life. Thus, cognitive development is a protracted process.
