Children in kindergarten, third grade, and fifth grade were presented a list of either pictures or words (with items presented varying numbers of times on the study trail). In both picture and word conditions, half of the subjects estimated how many times each item had been presented (absolute judgments) and the other half judged which of two items had occurred more often on the study trail (relative judgments). The primary findings were: (1) ability to encode and discriminate frequency for both pictures and words increased with age, and (2) picture-word differences (in favor of pictures) increased with age. The results lend support to a two-factor model of developmental change in frequency judgment performance involving pictures and words. The model provides for predictions concerning performance on verbal discrimination and recognition memory tasks as a function of age and stimulus mode, and also suggests further research to explain picture-word differences in verbal learning tasks. (Author)