Results of an experimental study of looking for a solution in a problem situation by younger schoolchildren (8-9 years old), adolescents (12-13), and senior schoolchildren (15-16) are described. So-called conjecture problems with undefined objects were used; subjects were allowed to ask "yes/no questions;!.. It has been found out that there develops with age a capacity to form a decision on the basis of gradual anticipation of a required solution.