| Age Range | Period | Description |
|---|---|---|
| 2 - 3 years old | Growing Period | Genetically prescribed neural networks sustain activities that occur automatically (e.g., breathing, sucking, metabolizing) |
| 4 - 8 years old | Learning Period | Children learn new things from observing things around them and from the people around them |
| 9 - 16 years old | Evolving Period | Children are able to judge right from wrong; they can modify what they have learned from past experiences and learn new things from new experiences |