Four experiments were conducted to assess the effects of certain stimulus variables on children's discrimination learning. In general, it was found that word frequency was negatively related to discrimination learning as long as the words were meaningful to the subjects. Moreover, the relationship between word and performance reversed in free-recall learning, as was expected. Equivalent relationships between frequency and learning were obtained with verbal and pictorial materials. The implications of these results were discussed in the context of popular accounts of memorial representation. (Author)