The two experiments investigated stimulus novelty which may affect reward and nonreward in a discrimination learning situation at different ages. The first experiment compared two types of "trial one" stimulus procedures on error tendencies following reward and nonreward. The two procedures differed with respect to novelty effects. One group was presented on the first trial with one of the two "trial two" stimuli, while the other group was given two stimuli on both trials. Reward was more difficult for the "one stimulus" group. In the second experiment, two groups were given a series of 24 problems with varied presentation to alter familiarity with the stimuli. One group chose between a novel and a familiar stimulus with the familiar stimulus rewarded half of the time and nonrewarded the other half. The other group was given stimuli but did not know whether its choices were rewarded. The first group chose familiar stimuli more often than the second group suggesting that the learning situation was more favorable. Results were specific to the use of "two dimensional" patterned stimuli which have little tactual appeal to children. (EK)