The article deals with the problem of the ability to use ideas about other’s knowledge and the ways of changing it, the ability to de-center thinking in the process of communication in the example of understanding deception in typically developing preschoolers and preschoolers with mental retardation. The recognition of deception is considered as a cognitive function, taking into account the specific techniques of the implementation of the mental model. Empirical sample of research: 72 children of pre-school age from 5 to 6 years. Contrast samples show the specificity of the lack of social interaction tools based on the mental model. Analyzed that in a game with deceit, a child is required to use signs to anticipate events that made it known about the nascent action of another person. In children with mental retardation in a game with deceptive action, shown a situational mode of action without taking into account the model of a mental interaction partner due to the lack of ability to decentration. The data reflects the relationship between the cognitive level of development and the level of the mental model in the process of forming the basis of social cognition and social experience in the early stages of ontogenesis.

The article discusses the role of the model of mental and separately the mechanism of joint attention in the normative age development of preschool children. It is shown that children with a lack of joint attention may experience difficulties in acquiring a wide range of developmental skills, and the ability to use the line of sight is part of a general mechanism that will further allow understanding and understanding the meaning of social information, the child’s ability to accumulate normal social experience. The hypothesis was verified that the developmental deficit of the mental model in children may be due to a decrease in the level of intellect: the difficulties of joint attention lead to an unformed component of the “objective-reflexive-normative thinking”. On a sample of 493 children of preschool age (typically developing and with mental retardation), a methodology was tested that assesses children’s understanding of the intentions and desires of others in the direction of gaze. It was found that the differences between typically developing children, children with lower bound and delayed age development can be tied to the fact that children who participate in joint attention can contribute to having more conditions to expand social learning opportunities. Changes in the accuracy of identifying the direction of sight shows the dynamics of the cognitive development of the child, which in comparison makes it possible to assess the characteristic differences not only in pathology, but at a decrease in the overall level of age development.

The article presents a study of the mental model deficit in preschoolers with mental retardation. The aim of this study using eye tracking is to identify markers that can predict the difficulties of social cognition associated with a deficit in the mental model in children with mental retardation. A comparative study of 64 typically developing preschoolers and preschoolers with mental retardation was carried out. To study the formation of a mental model, the paradigm of understanding false beliefs and experimental situations were used, which actualize in children the idea of the possible success of using and recognizing deception. Additionally, in the experimental situation, the method of registration of eye movement was applied to identify the level of the mental model. It is shown that with a deficiency of the mental model (from the point of view of understanding and applying false beliefs), there is a concreteness of perception, difficulties in using sign-symbolic means of social interaction, inability to suppress impulsive action and act from the position of a social partner. Children with mental retardation often turn not to sign-symbolic means, but to specific external signs of the situation: behavioral manifestations, actions, experience difficulties in distancing themselves from their own beliefs in order to rely in behavior on ideas about the knowledge of an adult. According to the results of an eye tracking study on heat maps of preschoolers with mental retardation, there is a deficiency of a gaze direction detector, which is necessary for understanding the intentions and predicting the actions of an adult. Eye movement analysis confirms that children with mental retardation often do not track the behavior of an adult and his reactions in situations of recognition and application of false actions.