During the war ideological pressure in society eased, and psychological theory and practices were permitted to grow. In Moscow State University a department of Psychology was opened in 1942. To chair it Sergey L. Rubinstein was invited from Leningrad. He also headed the research Institute of Psychology of MStU.

Rubinstein was a highly educated man. Son of a jurist from Odessa, after graduating from secondary school with a gold medal in 1908, he went to Germany for higher education. In 1914 he graduated from Marburg University, where he attended the lectures of Hermann Cohen and Paul Natorp, and in the same year he defended at Marburg University a Ph.D. thesis in Philosophy. When the First World War began he returned to Russia.

At the beginning of the 1940s, Rubinstein occupied all the key positions in Soviet psychology: he chaired the department of psychology of Moscow State University; he headed the Institute of psychology of MStU and the Department of psychology of the Institute of philosophy of the Academy of Sciences of the USSR. He was also the deputy director of this institute, an academician of the Academy of Pedagogical Sciences of the USSR established in 1944, and a corresponding-member of the „big" Academy of Sciences of the USSR (the only one among psychologists at that time). His book «Basics of general psychology» was granted a Stalin Award in 1942.

It was Rubinstein who invited Leontiev to a professorial position at the Department of Psychology in MStU.

But soon Rubinstein and Leontiev disagreed on the nature of psychic phenomena and personality. Rubinstein used to say that personality structure can be understood as an explication of inner drives and needs: "The outer is the incarnation of the inner". Leontiev argued that personality structure should be considered as the internalization of outward activity: „The inner is the incarnation of the outer". According to Rubinstein, psychological research should be aimed inward, into the depths of the human psyche, seeking the roots and sources of outward activity. According to Leontiev, it should be focused on outward activity, which is the key to understanding psychic structure.

Rubinstein objected to considering outward activity as a factor initiating and determining psychic functions. He wrote that outward activity should be considered as an interaction, an interrelation, between the individual and the material world around him, so that it is impossible to declare that outward activity is the initiating factor for psychic development.