Vygotsky’s Sociocultural Theory Lev Vygotsky, a Russian psychologist, developed a theory of cognitive development known as the Sociocultural Theory of Cognitive Development in the early twentieth century. The main assertion of the Vygotsky theory is that the cognitive development of children is advanced through social interaction with other people, particularly those who are more skilled. In other words, Vygotsky believed that social learning comes before cognitive development, and that children construct knowledge actively. Zone of Proximal Development Vygotsky is most recognized for his concept of Zone of Proximal Development (ZPD) pertaining to the learning process of children. According to the Vygotsky theory, children who are in the zone of proximal development for a particular task can almost perform the task independently, but not quite there yet. They need some help in order to perform the task successfully. For example, a five-year-old child knows