Sarah should first look for the original documents, starting from the Early Childhood Education Act with its subsequent approved laws to get informed by its theoretical fundamentation teor. The Early Learning U.S Government web page is recommended.
The above mentioned act was proposed in the early 60´s by Congresswoman Patsy Mink of Hawaii and consisted on concerns and proposals for children under kindergarten age which did not have so far, the proper ambiental and behavioral stimulation on pre-school age that would be determinant for their learning experience in future school years.
She should then, look for the part delivering information on the promotion of socialization with the legal landmarks attempting to guarantee pre-school experiencing for children, with professionaly oriented interaction with focus on developing boundaries, empathy, basic rationality and cooperation.