One control group and eight experimental groups, each composed of 12 first grade children, participated in this experiment. It was designed to investigate the effects of frequency of reinforcement and repeated evaluation of stimuli on the conditioning of preferences. Each child participated in the experiment for seven consecutive school days. The experimental children were divided into two stimulus condition groups; one received the same stimuli each session, and one received different stimuli from one session to the next. Each of these two groups was also divided into four rating groups. During a rating session, the child was asked to choose from 14 adjectives the one that he thought best described a particular Greek letter. A conditioning session consisted of a task involving reinforcement of particular Greek letters. The overall procedure allowed for the determination of any subject's change in preference for certain Greek letters as a function of either (1) number of evaluation sessions or (2) frequency of reinforcement. It was found that both factors affected preference. (WD)