The research objective is to show new possibilities for understanding cognitive interest as one of the indicators of personality development. Based on a systematic analysis, the authors clarified the content of the category of “cognitive interest”. A conceptual model of the dialectic of interest in knowledge was proposed. The principles that are the foundation of the process of its learning were revealed. On this ground, educational technology was developed. Long-term observations of the subjects of the educational process, conducted by the authors, allowed determining the dialectical connections of cognitive interest with thinking, attention, memory, speech, and emotions. The pro-posed model of the dialectic of interest in knowledge is conceptual, since based on it, the process of raising interest is built as a didactically thought-out system for managing children’s development, contributing to their personal growth, one of the components of which is educational technology.