The learning process becomes more thoughtful for toddlers as they approach their third birthday. They begin solving problems and performing mental trial-and-error instead of manipulating objects physically. As their understanding of cause and effect deepens, toddlers become more interested in mechanical toys and turning lights and appliances on and off.
- Shelov, S. P. (Editor-in-Chief). (2004). Caring for Your Baby and Young Child: Birth to Age 5. The American Association of Pediatrics. Revised edition. New York: Bantam Books.