Abstract
Improving the mental health of children is one of the main tasks for modern society. The aim of the work is to study the dynamics of mental health in preschool and primary school children under a psychological and pedagogical experiment. The study was conducted at 12 kindergartens (250 children) and three primary schools (200 children) in 2018–2019, in Moscow (Russian Federation). Children of each age group were divided into two groups according to the time spent on the Internet. The control group spent up to 15 min a day. The experimen¬tal group had an uncontrolled pastime. In total, there were four groups. The performance indicators (average score) and the dynamics of aggression were studied. The parents were provided with a survey. Children and parents had lectures with psychologists and teachers during the second academic year. The number of students with high academic performance increased by 1.4 times in 2019 compared with that of 2018 (p ≤ 0.05). Meanwhile, the number of students with low academic performance decreased by 1.3 times (p ≤ 0.05). The aggression in preschoolers improved during 2018. Thus, instrumental aggression in the experimental group decreased by 1.6 times (p ≤ 0.01), indirect aggression by 1.2 times (p ≤ 0.05), verbal aggression by 1.2 times (p ≤ 0.05). The control group indicators decreased by 1.7 times (p ≤ 0.01), 1.9 times (p ≤ 0.01), and 1.4 times (p ≤ 0.01), respectively. The level of aggression also decreased in 2019. In the control group, instrumen¬tal aggression decreased by 1.4 times less (p ≤ 0.05), indirect aggression 1.6 times (p ≤ 0.01), and verbal aggression 1.5 times (p ≤ 0.05). Meanwhile, the experimental group indicators decreased to a lesser extent: 1.2 times (p ≤ 0.05), 1.2 times (p ≤ 0.05), and 1.3 times (p ≤ 0.05), respectively. The child aggression can be associated with an extra time spent on the Internet and the conniving attitude of parents. Children from the experimental group demonstrated aggressive behavior 1.5–1.7 times more often than children from the control group (p ≤ 0.01). The survey of parents showed the same pattern. Thus, connivance of aggression and an aggressive reaction to communication with teachers were more significant (0.5–0.7 times, p ≤ 0.05) in the experimental group compared with the control. The improvement of the behavior of children was successful already after 1 year of the experiment. The academic performance improved, while aggressiveness decreased in all groups.

Key words: academic performance, aggressive behavior, children, improvement, preschool age, primary school age