Vladimir Ermak first introduced two important concepts of modern socionics further confirmed by Elena Udalova research. The first one is the growth dynamics which means that every horizontal block of two functions (see below) is filling in the certain age, from bottom to top, with the roughly 7-year interval, so that the lowest block is done before 7, the next is complete before 14, the weak part of the mental track is done before 21, and the top block finally leads after that. Due to this process, a child, or a teenager, may demonstrate faces of other sociotypes according to the active horizontal block. Besides, being introduced to the unknown people, or in stressful situations, people again may demonstrate adaptive or protective behaviour directed by the appropriate blocks (see below).