The effectiveness of acceleration training with children who were in a transition period was examined. Forty-eight kindergarten children were separated into four groups on the basis of their status (Preoperational vs. Transitional) and whether or not they received three sessions of inversion-negation training. The results of the immediate and delayed posttests indicated no difference due to the status dimension. However, differences as a function of training were manifest. The results of the investigation do not support Inhelder's contention that acceleration can only occur during transition periods between stages. (Author/CS)