A starting point in studying the psychic and mental development of a person through this approach is the analysis of the transformation of mental reflection into the process of the main object activities of play, learning, labor. The analysis is performed in both the phylogenetic and the ontogenetic aspect. The main feature of the activity is its subject, and the idea of unity between psyche and activity, activity and consciousness, activity and personality is a basic principle of modern psychology. In accordance with the action approach at the basis of personal development, the relations of hierarchy, consistency and dynamics of the main activities, which are the real determinant of the psychic structure of the personality.
Another important element of the business approach is the concepts of interiorization and exteriorization. Interiorsis is a mechanism of transformation of the subject into psychic, and the exteriorization is a process of transformation of the psychic activity into a subject. The approach to psychological research is organically related to the personal approach. The use of the personal approach requires the following basic requirements to be respected: compliance with the individual characteristics of the individual and the personality that are formed as a result of its particular individual living and working conditions; taking into account the motivational content of the activity of the person, with his needs, direction and ideals, with a correlation between the objective results of the habit and his / her internal / subjective / motivation; taking into consideration the individual features and nuances of emotionally sensual experiences of the person, her attitude towards her own destiny, the beauty and meaning of her life. In the last decades of the 20th century there has been a total orientation of scientific research towards the systemic approach, which is also orientated by psychology.
This approach implicitly involves activities and personalities. He reveals his possibilities in two directions: to reconsider the already established psychological knowledge, to create principally new theoretical hypotheses and experimental procedures. The basic requirements of the systemic approach to psychological discovery are the following: psychic processes, mental states, and the qualities of the personality; the system of "human mental structure" should be considered as a subsystem of systems with a higher level of complexity - family, group, team, respecting the principle that the theoretical systems created by the researchers that reflect the facts and the laws of the studied reality are an abstract analogue of the real object, and that this analogue is always with a simplified theoretical model of reality; to take into account the hierarchy and the dynamics in the formation and development of the needs and motives of the person, non-innovate goals and interests and the activities for their achievement; application of a historical approach to the study of mental phenomena; revealing the system of factors that are real determinants of the mental and personal development of man. On the methodology, the last empirical concretisation is the methods. In the psychology several groups of methods can be systematized. When selecting a method of psychological examination of the personality, it is necessary to observe certain basic principles, one of which is that of the leading role of the activity. This principle implies taking into account the action approach in psychological research, according to which the development of the pupil's psyche and personality is examined in relation to the main activities - play, learning, labor. In accordance with this principle of psychological-pedagogical facts, laws and mechanisms are seen as dimensions of three dimensions - past, present and future, focusing on the development process.