Sociocultural theory (see Chapter 3) identified three major classes of mediators interposed between learners and their environment: (1) physical mediators, such as material tools and technologies; (2) symbolic tools, such as signs, languages, and graphic organizers; and (3) human mediators, such as parents, teachers, peers, and other mentors. The learning process, therefore, is rarely immediate. Sociocultural mediators are ubiquitously present in the life of a child, first as a simple tool such as a spoon, with which the child develops motor skills, then as language that becomes a tool of thought, and then as a parent or teacher whose intervention ensures the child's acquisition of material or symbolic actions. From the very beginning children actively interact with the above mediators and with time internalize their actions as their own inner psychological functions.

This perspective, however, differs from that envisioned by Jean Piaget, whose concept of child development was probably the most influential psychological theory in the second half of the 20th century. This is how Piaget (1947/1969, p. 158) describes the interaction between infants and their environment: