Already in the 1920s, certain fields of scientific research were labeled "bourgeois" and "idealist" by the Communist Party. All research, including natural sciences, was to be founded on the philosophy of
dialectical materialism. Humanities and social sciences were additionally tested for strict accordance with
historical materialism. After
World War II, many scientists were forbidden from cooperation with foreign researchers. The scientific community of the Soviet Union became increasingly closed. In addition to that, the party continued declaring various new theories "pseudo-scientific".
Genetics,
pedology and psychotechnics were already banned in 1936 by a special decree of the
Central Committee. On August 7, 1948, the
V.I. Lenin Academy of Agricultural Sciences announced that from that point on
Lamarckian inheritance, the theory that personality traits acquired during life are passed on to offspring, would be taught as "the only correct theory". Soviet scientists were forced to redact prior work, and even after this ideology, known as
Lysenkoism, was demonstrated to be false, it took many years for criticism of it to become acceptable. After the 1960s, during the
Khrushchev Thaw, a policy of liberalization of science was implemented, but the policy of Lysenkoism continued. Lysenkoism was officially renounced in 1964, after
Leonid Brezhnev came to power. ==After Soviet collapse==