Background. The research of the student attitude to the system of supplementary education is of  paramount importance as it is the system of supplementary education where the adolescent tries to implement specific "cultural tests" that allow him/her to obtain an inverse social reaction regarding his/her personal success (success as a subject of activity).

The Objectives of the research are as follows: 1. Determining the influence of age, social demographic factors on the involvement of adolescents in the system of supplementary education is the objective of the research. 2. Defining the motives determining the occupations of students of the secondary and high schools in the circles, studios, sections. 3. Studying the influence of the student involement in the system of supplementary education on their studies.

Research Progress. The paper presents the results of the research carried out by the Center for the Sociology of Education of the IEM RAE in October-November, 2017. The sample includes 11,803 school students of 7-11^th grades of the Leningrad region, Russia. Questions concerning the student involvement in the system of supplementary education, paid vs free school classes in various circles, studios, sections, preferences of certain areas of supplementary education, variety of motives that make students get interested in different types of extra classes are discussed. The influence of extra classes on the studying activities (academic success, student status in the classroom, peculiarities of motives involved).

Research Results. In the system of supplementary education, every second student of the secondary and high school is engaged. The educational status and financial position of the student's parents influence his/her involvement in the system of supplementary education. The influence of macro-indicators (settlement factor) is marked as preference in the field of studies and also within the payment strategy of the educational services provided. Among the main motives for attending classes there are the following ones: broadening the horizons, assessing the abilities and opportunities.

Conclusion. The most important motive that causes adolescent interest in various types of jobs and occupations in the system of supplementary education is to catch up with the lack of knowledge obtained in school. The student’s involvement in the system of supplementary education also sets a positive vector for his/her development as subject of the studying activity. 

The paper is devoted to the concept of «zone of proximal development» (ZPD). This fundamental concept is revealed in the framework of the ergative model of the subject of work and learning. The prime postulate of the model is the statement about the genetic unity of the subject of collective activity (the ergasystem) and the individual subject. The similarity of structures was followed by the cultural and historical development of homo sapiens, which occurred in the labour conditions that promoted building human relations. Generalized functions in the ergasystem and the corresponding positions can approximately be as follows: «executor», «leader», «ideologist» and «strategist».

The paper states that the subject of educational activity is represented by the same basic characteristics. At any learning stage, the teacher must judge the necessary pedagogical influences according to which subject positions to be improved. Using the ZPD toolkit, the teacher directs efforts to raise the general maturity of the learner, which will develop the ability to learn independently.

In order to verify the assumption mentioned above, the method of the teaching experiment was used, during which the students of the secondary vocational education and high school students were attending additional training courses at the Department of Further Education, The Small Academy, Lomonosov Moscow State University. Extra training courses included project or research activities of trainees, so groups of students acted both the subject of collective work and the subject of learning. The first results of the pilot experiment showed that productive work of the teacher and student can be carried out at the intersection of the subject spaces of these activities, where the boundaries of the ZPD can be outlined.