Factors of cognitive complexity of test questions in psychophysiological studies

The paper presents the results of a study of the functional state evaluations of the brain during auditory perception. The subjects listened 60 questions with different linguistic characteristics, taken from polygraph database templates, and answered to them. This characteristics: is the number of different types of words, the percentage of words from different parts of speech, the number of negations, the presence of forms of personal pronouns and their place in the question, the number of letters, the percentage of vowels, the position of intonational stress. As psychological characteristics that affect the functional state of the brain, the following were measured: verbal intelligence according to the R.Amthauer’s test, personal and situational anxiety according to the Spielberger — Khanin test. To measure the functional state of the brain, a 19-channel EEG was recorded in the 10–20% system. The functional state of the brain was assessed by calculating the fractal dimension of the EEG using the method. The sample consisted of students and employees of a number of educational institutions in St Petersburg, 9 men and 8 women aged 19 to 59 years. An analysis of the experimental data made it possible to confirm the hypothesis about the influence of the measured questionnaire characteristics, the linguistic characteristics of the questions, and the psychological characteristics of the subjects on the fractal dimension of the EEG. EEG analysis in various leads revealed two EEG “complexity” factors related to the frontal and occipital areas of the brain. A regression model was obtained for assessing the cognitive complexity of a particular test question, which is reflected in the complexity of the EEG curve of the subject perceiving this question. The resulting model allows you to select questions for psychophysiological examination that have the required level of cognitive complexity. The results of the work testify to the importance of such an indicator as the fractal dimension of the EEG for studying the functional state of the brain and its dependence both on the personal and biological characteristics of a person, and on the emotional state and complexity of the information received by the analyzers.