College students were trained on a conditional discrimination problem consisting of two stimulus dimensions and a conditional cue dimension, and then were given conditional intradimensional (ID) or extradimensional (ED) shift. The combinations of stimulus dimensions and conditional cues in the original and shift discriminations were the same for ID shift and different for ED shift. When Ss were trained on the original discrimination to reach the criterion (8/8) no significant difference was found between ID and ED shifts. When Ss were overtrained, ID shift learning was significantly faster than ED shift, which indicated that ID shift tended to be easy and ED shift difficult after overtraining. The results may be explained by assuming that what is learned in conditional discrimination changes from the connections between stimulus values and conditional cues into those between stimulus dimensions and cues with increasing amount of training.