The aims of this study, suggested by the hypothesis of acquired distinctiveness of cues and by the method of Spiker's experiment, are to clarify that the everyday language is the most effective ADC for delayed discrimination learning (Exp. I), and that the more familiar, the more frequent in usage, the language gets the more effective ADC function (Exp. II). Exp. I Procedures: The Ss receive one of the following six types of stimulus pretraining. As stimulus, pairs of a triangle and a square figure are used. Each figure has four variations about color and size. After that, Ss are asked to discriminate that either triangle or square is baited, in the delayed reaction experiment. Number of correct responses are counted. Ss: The Ss are 90 three-year olds and 90 five-year olds children. They are divided evenly into six groups at each age level, according to the six types of pretraining. Types of stimulus pretraining: 1) Relevant word group (to learn relevant form names) 2) Meaningless word group (to learn to associate nonsense syllables with the figures) 3) Motor cue group (to learn to associate raising right or left hand with one of two figures) 4) Perceptual cue group (to learn to associate white or black card with one of two figures) 5) To see and discriminate group (to learn to say “same” or “different” with a pair of figures) 6) Showing group (to watch two figures for five seconds) Exp. II Procedure: Except that pairs of a square and a pentagon figure are used as stimulus, other procedures are all the same in Exp. I. Ss: The Ss are 72 three-year-olds children and they are divided evenly into the the following six stimulus pretraining groups. Types of stimulus pretraining: 1) Relevant word group 2) Overlearning meaningless word grop (to perform the 100% overlearning to associate nonsense syllables with figures) 3) Meaningless word group 4) Motor cue group 5) Perceptual cue group 6) Showing group The results are as followings: Exp. I:(1) In younger children, relevant word group, motor cue group, perceptual cue group, each shows more superior performance than any other control group, and relevant word group is the best among them. So, it is supported that the everyday language, relevant names of objects is the most effective as discrimination cues.(2) In younger children, perceptual cue and motor cue groups show superior performances than either to see and discriminate or showing group. Then, if provided any concrete cues, the task becomes easier for Ss than without cues.(3) In older children, there are not any significant differences among six groups and each group shows very high performances. It is probable that the older children would have already developed the ability to use internal speech as a substitute for external ADC. Exp. II,(4) Relevant word group shows superior performance over overlearning meaningless word group, which is superior to meaningless word group. So, our major hypothesis is supported.(5) Motor and perceptual cue groups show superior performances to showing group. It is demonstrated that perceptual or motor cues other than language are able to be effective as ADC or mediator in younger children.