Relevance. The study of human functional states within the structural-functional approach is an important development in work psychology. As work becomes more intensive and cognitive, the study of mental fatigue becomes more important.

Objective. To validate cognitive tests for the assessment of mental fatigue cognitive effects, and to replicate cognitive effects of fatigue observed within the structural-functional approach.

Methodology. 27 subjects (18 male), engineers in a high-tech engineering firm, and took part in the study conducted over a working day in the morning and in the evening. Mental fatigue was assessed with a questionnaire. The cognitive tests included a test of attention switching, a test for working memory, and the Sternberg’s short-term memory search task.

Results. A reduction in attention switching and memory search efficiency was found. These results in a good concordance with previous results and indicate a reduction in the availability of top-down cognitive control resources. Evidence was found for transition towards sequential self-terminating memory search strategy under mental fatigue. No reduced working memory was found, which may be related to the meta-cognitive regulation of functional states.

Conclusions. Mental fatigue is associated with a reduction in the control of attention and short-term memory, related to the depletion of cognitive control resources. Individual cognitive reactions to fatigue are important. Future developments of the structural-functional approach may include the development of new diagnostics tools, the usage of cognitive modeling, the orientation to the analysis of the individual differences, and the integration of the structural-functional approach with resource approaches to cognition.

The article substantiates the influence of the planning style of activity on the reliability of the driver's activity. The work includes the description of the process of creating and approving the questionnaire "Individual style of driver's activity". The questionnaire contains questions assessing the means used by the driver to carry out activities (in particular, referring to the preservation of information on the road environment, schemes for organizing traffic on a particular route). Data on the reliability of the questionnaire (internal consistency and retest) are presented. The procedure for estimating the compensating effect of the planning style of the driver's activity on the reliability of the activity with a low speed of switching of attention is described. Compensation effect was determined by the ratio of the level of compliance with the requirements of the activity for the speed of switching of attention and the formation of a planning style of activity. The reliability of the drivers' activity was evaluated by a group of experts by recording the number and type of accidents involving drivers. The correlation between the reliability of the driver during life and during the last year was investigated. A higher level of reliability of driving activity is determined by a combination of a higher social status of the driver, with its greater connection with the transport sector, a more mature age, a more markedly planned style of activity, and a higher level of reliability of activities throughout life.