The term “school age” carries significant meaning in American society. The day a child walks through the schoolhouse doors marks an unforgettable benchmark for the young student and his or her family. Of course, the first day of kindergarten is not the first “teachable moment” the child has experienced. A vast amount of learning has preceded that eventful day. Knowledge, skills, and abilities have been acquired and practiced at home, in the playground, and – for the majority of children born in the 21st century – in child care settings. The difference between “preschool” and “school age”, then, is not really about teaching and learning but about where and how these activities take place, and who assumes responsibility for them.

In the United States today, formal schooling is largely the responsibility of state and local governments. In most communities, children are eligible to enroll in the public education system when they are about five years old. Historically, it was not unusual for children to be admitted at younger ages. The first kindergartens in America commonly served children younger than five – for example, New York City schools admitted four-year-olds, and Boston's public schools enrolled toddlers as young as 22 months (Mitchell, Seligson, & Marx, 1989). Wisconsin's state constitution has contained “a commitment to free education for four-year-olds” since the middle of the 19th century (Barnett, Hustedt, Robin, & Schulman, 2004, p. 170).