This document discusses cognitive development in early childhood from ages 2 to 6. It covers Piaget and Vygotsky's theories of cognitive development, including Piaget's stages of preoperational thinking and obstacles to logical operations. Vygotsky's perspective on social learning and scaffolding is also discussed. The document then covers children's theories of mind, understanding of belief vs. reality, and language development including vocabulary, grammar, and bilingualism. Finally, it briefly discusses different approaches to early childhood education.