Abstract: The purpose of this study was to explore the problem of the development of children's ability to generalize terms. Nine groups of sentences were used as test materials, in which consisted of one, two or threeterms ("factors"). Subjects were required to generalize them. The subjectswere pupils from 9 to 12 years old, and those of 8.5 years old. Each age groupconsisted of thirty children with a totality of one hundred and fifty pupilsin all. The results indicate: The development of children's ability to generalizeterms is not completely identical with the increifse of, age. It is different inspeed and grade. Between the age group of 8.5-9 and the age group of 11-12,the differences are significant. But in other age groups, the development ofthe ability is slow. There is difference in the extent of generalizationbetween each group.

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