As children gain an understanding of and appreciation for the feelings and actions of others, they will gradually stop competing and learn to cooperate when playing with friends. Often, they are able to work out their own solutions to disputes by taking turns or trading toys. They learn to use words to describe their feelings and apologize when they’ve done something wrong.
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.