One of the most important contributors to our understanding of cognitive development is Russian psychologist Lev Vygotsky (1896-1934). Although his work was conducted in the 1920s and 1930s, his writings continue to influence present-day studies in childhood cognitive development.
Vygotsky was similar to Jean Piaget in that he believed experience with the physical world is an important factor in cognitive development. He placed much greather emphasis on the culture and social setting the child lives in and interacts with than Piaget though. Vygotsky noted that children do not learn to think about the physical world in a vacuum.¹ The cultural context in which they learn -- what they hear others say about the world and how they see others interact with the physical world -- matters.¹
Building on this basic postulate, Vygotsky believed that parents, teachers, friends and other children are important in helping children acquire and develop ideas about how the world works.
According to Vygotsky, language is the basis for cognitive development. This includes the ability to remember, solve problems, make decisions and formulate plans. Until around the age of seven, children vocalize many of their thoughts. Where Piaget may hypothesize that this reflects egocentrism, Vygotsky would say that the child's talk reflects a cognitive developmental process. After this age, Vgotsky labels their thoughts as inner speech. This represents the the internalization of words and the mental manipulation of them as symbols for objects in the environment.¹
The skills and problem solving abilities that a child can show on his or her own indicate the level of the development that the child has mastered. Vygotsky called this the actual development level: the stage of cognitive development reached by a child, as demonstrated by the child’s ability to solve problems on his or her own.¹ Vygotsky calls the the increased capacity for problem solving that results from guided help as zone of proximal development: the increased potential for problem solving and conceptual ability that exists for a child is expert mentoring and guidance are available.¹