B. A Psychic set-up is shaped by the specific pattern of the interaction of the individual with the environment.

C. The Psyche displays itself in the process of active interaction of the individual with the environment, and investigating this process of interaction is the right way to analyze and explore Psyche.

These Rubinstein positions laid the foundations for Russian psychology of the Soviet period. For the greater part of the XXth C, Activity Theory in Russia was the indisputable methodological basis of all psychological research, bearing the official label of the "right" Marxist psychology (and after the 1923 no psychology but Marxist was legitimate in Russia[16]). On this basis a number of brilliant theories emerged.

Internationally, Russian AT is mostly known by the few translated works of Alexei N. Leontiev, by his theoretical model of activity (Activity – acts – operations (Leontiev, 1976 Russian, 1978 English). Leontiev (1903–1979) developed his theoretical model as a rather late invention (in the 1970s) of his lifetime, and it should not be supposed to be Russian AT as a whole. The Ruian AT trend, though integrative, was never a monolithic one. It comprised a set of psychological theories, more or less divergent, developed by Sergey L. Rubinstein (1889–1960), Boris G. Ananiev (1907–1972) and others. In the Russian literature this trend is named the "Sub'ekt Approach".

Leontiev himself wrote, that activity in psychological science can be approached in two ways: a) as a research of psychological aspects of activity (and all psychological schools and even all sciences can be engaged in research of activity); b) considering activity as the generating source of psyche development (Leontiev, 1986). Leontiev acknowledges and stresses that AT is the "b)" approach. Still, in his works which were translated, the "a)" approach seems more articulated. But there are his other works and especially works by Rubinstein and Ananiev (the so called "Leningrad school"), where the generative function is well explained (Mironenko, 2009a). The "b)" approach is naturally focused on ontological problems.

Considering the place of Russian AT in the history of international psychological science, Rubinstein designated as the primary achievement and the basic sense of AT the overcoming of the separation of psyche from the physical world, the disruption of the so called psychophysical parallelism. AT opened the way to use the principle of determinism without simplification and reduction of psychic phenomena, considering psyche as an element of the real life in the real world, as an attribute of evolution (Rubinstein, 1945).