Russian scientist who contributed to the theory of socio-cultural development, the study of the relationship between learning and development, the role of speech and language in the development of higher mental functions. Theory and discovery: Vygotsky developed a theory of sociocultural development that emphasizes the role of social interaction and culture in the formation of cognitive functions. He also studied the role of speech in the development of thinking.A key contribution is the idea that higher mental functions (thinking, speech, memory) have a social origin. They are formed during the child’s lifetime through the assimilation of cultural signs (for example, language) in communication with adults. The significance of his works is enormous: he radically changed the understanding of the development of consciousness, laid the foundations of Russian pedagogical and child psychology, and his ideas became extremely popular in the West in the second half of the 20th century.