Younger schoolchildren have been asked in an experiment to solve and make up logical problems. It is shown that mental processes in making up a problem ("author's thinking") go on in a different way as compared with the problem-solving processes ("synthesis through analysis"). Efficiency of the "author's thinking" is measured by the degree of problematicity, originality, and complexity of the made up problems. Dynamics of the "author's thinking" by the above criteria during the study in the elementary school is shown.