Social development theory was introduced in 1920s and 1930s by Lev Vygotsky. This theory gives a framework for cognitive development argues that the key role in cognition development lies in social interactions. In his own words, “every function in the child's cultural development appears twice: first, on the social level, and later, on the individual level; first, between people (interpsychological) and then inside the child (intrapsychological). This applies equally to voluntary attention, to logical memory, and to the formation of concepts. All the higher functions originate as actual relationships between individuals”¹⁾.