The final paper describes the theoretical background essential for understanding the cognitive development of a preschool child and the NTC learning system, which is focused on the realization of all the child's biological potential. The first part of the paper helps us to understand cognitive development by carefully bringing facts about the important processes that occur in the process of development. The paper is initially focused on the development of neurons and synapses in the brain, then looks at the roles of the two brain hemispheres. The paper briefly describes MacLean's triune brain theory and Jean Piaget's theory of cognitive development, which represent an important component in understanding brain development. At the end of the first part of the paper, cognitive development and its essential features are defined. The second part of the paper presents the NTC learning system designed by Dr. Ranko Rajović. The process of the creation of the program itself, its goals and features, as well as the methods of work and realization of the program are described. The end of the second part of the paper defines the roles of educators and parents in the cognitive development and in he NTC learning method promotion of the child and the promotion. The last part of the paper presents some of the activities within the NTC learning system that were carried out in one of the Zagreb kindergartens. Throughout the paper, an emphasis in put on the the importance of early stimulation and social support for not only child's cognitive, but also overall development.