In two experiments, subjects either read a bracketed word in a sentence or generated a word in response to its definition. A word-fragment completion test was then carried out. In Experiment 1, children's priming under the generate condition was substantial, as compared with baseline performance, but was significantly lower than that under the read condition, whereas there was no difference in adults' priming between these two conditions. Furthermore, prior generation induced an age-related increase in priming despite no age difference under the read condition. In Experiment 2, mentally retarded persons exhibited a profile similar to that of children. These results suggests that there are two different components in implicit memory, one that shows no developmental difference and heavily relies on perceptual processing and the other that shows an age-related or intelligence-related increase and heavily relies on conceptual processing.