Introduction In the process of working with people, it is occasionally necessary to consider the behavior of some personalities and draw conclusions regarding this or that manner. This procedure is called perception checking and is characterized by the need to analyze certain human actions, gestures, and phrases. The use of this practice in law enforcement structures has psychological significance since a correct evaluation of both verbal and nonverbal behavior features can be useful as a successful mechanism for communicating with different people. In order to follow the conditions of perception checking, it is essential to be guided by different ways of interpreting and, if necessary, to receive clarifications concerning this or that form of behavior. The correct interpretation of certain motives can serve as a valuable quality of a law enforcement personnel and be of importance for working with suspects or criminals. Human Behavior in Stressful Situations The peculiarity of the procedure of perception checking is that it is not based on the first impression of what is seen or heard. Otherwise, the initial interpretation of a particular gesture or phrase may be erroneous. It is especially significant to monitor it in the process of interaction with people who are in stressful situations. Possible reactions of a person to stress can be divided into three groups – constructiveness, excitement, and rejection. It can be the conscious mastery of the situation and its transformation into constructive behavior without any distinctive features. Further, there are impulsive reactions, worsening relations with other people, and giving way to negative emotions. Also, it can be an attempt to reject the problem and protect oneself, which often happens unconsciously. When using all these evaluation criteria in the practice of law enforcement agencies, it is possible to derive substantial benefits from such knowledge. If a criminal shows non-standard forms of behavior, it can be used as an evaluation mechanism. Thus, very often, in conversations with security guards, offenders and suspects can unconsciously express some inner feelings and considerations. Eyebrows movements, fingers tapping on the table, and nervous glances may indicate a stressful state and help to determine the degree of guilt of a particular person. Fear is manifested in anxiety, excitement, guilt, and other factors. The practical implementation of perception checking can consist in the correct interpretation of all those features of behavior that are visible during observation. The feeling of anxiety, as a rule, is expressed visually, and it is difficult for an unprepared and especially emotionally unstable person to control some gestures that are made unconsciously. Consequently, monitoring an individual in a stressful situation can allow accurately assessing the feelings and experiences of the person. However, it is essential to interpret specific manifestations of emotions correctly and not to make mistakes in the evaluation so as not to come to false conclusions. Interpretations of Stressful Behavior Despite the fact that stressful situations are almost always reflected in the behavior of peopl