The present paper investigates the study of features of brain activity by the process of change the regimes of information associated with the stages of understanding of the meaning of visually presented texts in adult subjects (n = 148). Researchers have developed an original methodology of step-by-step presentation of the texts. This technology has allowed the researchers "to catch" a psycho-physiological markers of understanding and identify the stages in a temporal sequence of the process of understanding. EEG data was analysed using spectral and non-linear methods. Was highlighted three stages: "before understanding", "understanding" and "after understanding". The study discovered the phenomenon of V- shaped changes to the values of the fractal dimension of EEG. The first stage is characterized by the increasing of the power spectrum of EEG in the high frequency range and increase the value of the fractal dimension of EEG, what probably reflects the process of the generation of ideas and the search of solutions. At the next stage ("understanding") a decrease in the value of the fractal dimension of EEG was registered, and an increase of the power spectrum of the low-frequency range. This seems to reflect the simplification of the invariance of reality to the only valid alternative. The last stage is characterised by the increasing power spectrum of EEG in the high frequency range and increase the value of the fractal dimension of EEG, which can reflect the process of intensification of activity of the brain associated with the verification of the correctness of the decision. The results obtained allow an approach to the understanding of the physiological mechanisms of the reorganization of the system of brain activity in the process.of understanding of the meaning of visually presented texts. This, therefore, outlines the path to the elimination of existing contradictions in the literature relating to the role of high- and low-frequency components of the EEG as markers of the state of understanding.