UDC 51-77 The Research of Loss Stability of Level of Psychical Reaction of a Human with the Power of Informational Influence on Him A. N. Kudinov, E. V. Chusova Department of Mathematical Modelling Tver State University 33, Zhelyabova str., Tver, Russia, 170100 In recent years significantly increased the negative information and psychological impact on the individual and mass consciousness. <...> Therefore, strongly expressed of emergence of aggression, anxiety, despair, hopelessness, depression, a criminal manifestations and mental illness. <...> The research of stability of level of psychical reaction with personal characteristics of a human and with the power of informational influence on him is presented in the article. <...> The adjoin method offered by Kudinov A.N. was applied to research of the loss of stability. <...> The main advantage of the adjoin method is that for use to the problems of dynamic stability studies in various fields of science, technology, biology, medicine and psychology, if their equations can be reduced to the equations of second order, don’t demand the introduction of Lyapunov functions. <...> The adjoin method permits to find the equilibrium positions and to check the stability of nonperturbed state. <...> Also the research of stability by Lyapunov’s method on first approximation is conducted, as a result the stability conditions of psychical reaction with personal characteristics of a human and with the power of informational influence on him are presented. <...> Introduction impact on the individual and mass consciousness. <...> Strongly expressed of emergence of social tensions, aggression, anxiety, despair, hopelessness, criminal manifestations and mental illness. <...> In recent years significantly increased the negative information and psychological 2. <...> Mechanical system of level of psychical reaction of a human on of informational influence has the form: md2Y dt2 +rdY dt +cY = X, (1) wherem—inertial mass of the system, r—coefficient of viscous friction, c—stiffness. <...> If some of the force X acts on the mechanical system, then the system is set in motion (begins to move) [2]. <...> Also there are different losses, and the amount of movement Y is connected with the value of X the differential equation of dynamics. <...> If the force X is force of information influence (S), and Y is level of psychical reaction of the person (K), then m, r and c are characteristics of the person P (rigidnost, frustrirovannost and aggression <...>