We are in a position to close the circle of our discussion and to return to what was indicated at the beginning of this work by the patterns that control the development of the practical intellect of the child, which is only a specific case of the patterns of construction of all higher mental functions. The conclusions we reached confirm this and show that higher mental functions arise as a specific neoformation, as a new structural whole that is characterized by the new functional relations that are being established within it. We have indicated that these functional relations are connected with the operation of using signs as a central and basic factor in the construction of every higher mental function. Thus, this operation appears to be the common trait of all higher mental functions (including the use of tools, which is always our point of departure), a trait that must be taken out of parentheses and subjected in the conclusion of our study to special consideration.