As briefly discussed in Chapter 1, Vygotsky and his followers view school instruction as the major avenue for mediation and, therefore, as the major contributor to children’s development during the period of middle childhood. According to the Vygotskians, the major reason for the development-generating effect of school instruction relates to students’ acquisition of scientific knowledge, which can be contrasted with the everyday life knowledge of preschoolers.

Everyday life knowledge is the result of generalization of children’s personal experience in the absence of systematic instruction. Therefore, such knowledge is unsystematic, empirical, not conscious, and often wrong. For example, the concept of a bird that young children develop includes the ability to fly as the major characteristic of birds; therefore, preschoolers do not define a penguin as a bird. Similarly, a three-year-old child, having observed a needle, a pin, and a coin sinking in water, comes to the wrong conclusion that all small objects sink and begins to use this rule to predict the behavior of different objects in water. Despite its “unscientific” nature, everyday life knowledge plays an important role in children’s learning as a foundation for the acquisition of scientific knowledge. For example, learning different species by school students requires that they have some understanding what animals are and know at least several representatives of the animal kingdom.