Abstract
Following facts about the process of the development of self-cognition have been definitely revealed with dairies of school children (from the 1st to 5th grade).
(a) Self-cognition is possible only through others.
(b) At first, cognition is one of the external (behavior) of self, but gradually it developes into one of the internal (consciousness) of self.
(c) At first, cognition is one of present self, subsequently becomes one of past self.
(d) At first, self-cognition is possible through others as individuals, but next through others as groups. And at last, self-cognition becomes cognition of self as an individual in a groups.