The purpose of this study is to re-test the “deprivation and satiation effects” of a social reinforcer and to emphasize the importance of the behavior under the satiation and deprivation treatment. In experiment I, effects of satiation and recovery of a social reinforcer were tested. Subjects were from 5 years and 7 months to 6 years and 6 months boys. Experimental design was 3 (satition level) × 2 (recovery interval) and there were four subjectes for each group. Subjects were individually brought to a experimental room and asked to wait while see some nursery books. For 8 minutes, an experimenter presented approvals with the word “orikosan ne” 1, 4, or 16 times, and then there was a 1-or 8-minute recovery interval during which the stimulus was not dispenced This was followed further by a discrimination test under continuous reinforcement with “oriko-san ne”. Mean number of correct responces was inversely related to the preceeding satiation level only when the 8-minute deprivation interval was followed. This result was considered because of the subject's behavior under the satiation and recovery treatment. In Experiment II, the effect of subject's behavior was tested by using the condition of 16-time stimulus presentation and 8-minute recovery interval, and there were two groups differing in behaviors under the two treatments. In one group subjects were demanded different behaviors under the two treatments (W-R group), and in the other, the subjects behaved the same under them (W-W group). It was expected that in W-R group, the social reinforcement efficacy would be high and in W-W group the efficacy would be low. Subjects were boys from 6 years to 6 years and 9 months. The number of subjects for each group was 10. The subject's behavior under the satiation treatment was card sorting, and the behavior under the recovery treatment was seeing nursery books. But in W-W group the subjects sorted cards again. The other procedures were the same as in Experiment I. The result was as expected. The mean number of correct responces of W-R group was significantly higher than that of W-W group, and it was confirmed that the satiation and deprivation effect of the social reinforcer is dependent on the recipiant's behavior. These results were discussed from behavioral and cognitive standpoints and the necessity to point out the mediator between operation and performance and the importonce of poining out the relations to others (ie. operation and performance) was emphasized.