The initial and posttraining form or color dominance of ninety-six 4–7-year-old children was assessed. The Ss were assigned to one of 3 groups for discrimination training. One group, the Reinforcement Group (Group R), received differential reinforcement on their dominant and nondominant dimensions. Correct responses to the discrimination involving their preferred dimension were reinforced on an FR 5, while their nonpreferred dimension was reinforced on a more dense schedule, FR 2. The Verbalization Group (Group V) received the same reinforcement conditions and in addition were required to verbalize on each training trial, where appropriate, the class name of their nondominant dimension prior to performance of the overt motor response. Group C was the control condition and they received nondifferential reinforcement and no verbalization training. It was hypothesized that Group R would change responding in the direction of the more dense schedule and would switch dominance due to the differential reinforcement and that Group V, due to the added verbal response produced cue, would switch dominance even more than Group R. Overall, the hypotheses were strongly supported. The results indicated that form and color dominance is modifiable by certain experimental manipulations and that both differential reinforcement and verbalization training are potent and effective variables in producing this response change and subsequent transfer.