Principles of child development and learning that inform developmentally appropriate practice Taken together, these core values define NAEYC’s basic commitment to children and underlie its position on developmentally appropriate practice. Developmentally appropriate practice is based on knowledge about how children develop and learn. To guide their decisions about practice, all early childhood teachers need to understand the developmental changes that typically occur in the years from birth through age 8 and beyond, variations in development that may occur, and how best to support children’s learning and development during these years.