The notion that children's early experiences are biologically embedded is gaining further support from research showing that the development of children's endocrine and immune systems are also influenced by children's environments during the early years (Barr, Beek and Calinoiu, 1999, Gunnar, 1998, McEwan, 1998). For example, children develop their literacy skills in a cumulative way as they move from one stage to the next. The rate at which they develop these skills depends on the strength and duration of their exposure to the family, institution and community factors that comprise the Foundations for Success in the Educational Prosperity model.