The purpose of the present experiment was to test the hypothesis that ease of reversal shift learning in kindergarten children is positively related to the S's abstraction ability. This hypothesis was deduced from the verbbal mediating response theory (kendler & Kendler, 1962). 160 kindergarten Ss were given an abstract word test consisting of 20 items of two objects in each. The Ss were required to guess an abstract word common to the two objects, e. g., "What is the common property to a sparrow and a swallow?" Based on the test, 40 Ss were selected from the upper end of the scores and 40 Ss were from the lower end, and then they were trained on a discrimination and a reversal. A two-dimensional, size and brightness, discrimination task was used, which consisted of two pairs of squares, i. e., large black and small white, and large white and small black. The Ss first learned the discrimination task with one of the following as the positive stimulus : large, small, white, and balck. Upon completing the discrimination, Ss were given a reversal shift without further instructions or any interruption. The learning criterion in the discrimination and reversal was nine out of 10 succssive correct responses. The main results were as follows : (a) No significant difference in the discrimination performance was found betwee the high-abstraction ability (HA) Ss and low-abstraction ability (LA) Ss, and (b) the HA Ss learned faster the reversal shift task than the LA Ss when the brightness dimension was relevant, but no significant difference in the reversal performance was found when the size dimension was relevant. The findings supported the present hypothesis, and were discussed with reference to the Kendlers' verbal mediational model.