a direction in Soviet psychology that regarded psychology as the science of behavior of living creatures, including man. Reactology was founded by the Soviet psychologist K. N. Kornilov.

Reaction, the central concept of reactology, was considered universal for all living creatures and embraced all reflex movements of organisms, including unicellular organisms. It was seen to possess psychological characteristics in higher forms of the animal world and was viewed as the response of the whole organism and not that of a single organ. Reactology sought to study the speed, force, and form of a reaction by means of chronometric, dynamometric, and motor-graphic methods; the experimental data obtained represented a significant contribution to Soviet psychology.

The proponents of reactology believed that reworking the concept of reflex and broadening it to the category of reaction made it possible to synthesize subjective and objective psychology. This synthesis, however, was artificial. Reactology was built on an eclectic combination of Marxist principles with some mechanistic and energist ideas—such as the law of unipolar loss of energy—that were first formulated by Kornilov in his Theory of Reactions (1921). As a result, a contradiction soon emerged between the correctly set tasks of the new psychology and the scantiness of its specific content. The psychological discussions of the early 1930’s led to the rejection of reactological concepts.