There is also a discrepancy between the ability to form concepts and identify them. Abstract concepts can be explained with concrete terms and examples. Sakharov found that the stages of concept formation begin in childhood, but the intellectual functions develop at puberty. Vygotsky observed that the ascent to concept formation follows phases with sub-stages. Once children move to forming concepts, they never realize the change probably because they do not use meta-cognition.
True concepts begin to be formed with increasing fluency.
However, the elementary forms are not abandoned. Instead, human beings vacillate between complexes and concepts. Spontaneous concepts are nonconscious, whereas scientific concepts are concepts taught in school. Vygotsky defined systematization as contact with scientific concepts. Vygotsky found that as long as curriculum supplies the necessary material, the development of scientific concepts runs ahead of the development of spontaneous concepts.