Preschoolers are becoming increasingly independent and want to make more of their own choices. Eager to prove how capable and self-sufficient they are, they run ahead of caregivers on walks, insist on choosing their own clothes or meals, and begin to challenge authority.
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.