Throughout the second year, toddlers will constantly swing back and forth between fierce independence and a desire to cling to their primary caregivers. Now that they can walk and do things for themselves physically, they have the power to move away and test their new skills. At the same time, most are not completely comfortable with the concept that they are individuals, separate from their parents and the rest of the world. Some people call this period “the first adolescence” because it reflects the mixed feelings toddlers experience about growing up and leaving their parents.
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.