This document discusses several theories of cognitive development, including Vygotsky's sociocultural theory and information processing theories. Vygotsky believed that social interaction and culture play important roles in cognitive development. His theory emphasizes how learning occurs in the Zone of Proximal Development through social interactions. Information processing theories view thinking as information processing and examine the mechanisms, structure, and assumptions of the cognitive system. The document provides examples of applying Vygotsky's theory in classrooms and socialization to enhance children's cognitive development.