This paper reports evidence from a longitudinal study in which children's attention to shape in a laboratory task of artificial noun learning was correlated with a rate shift in noun acquisitions. Eight children were tested in the laboratory at 3-week intervals beginning when they had less than 25 nouns in their productive vocabulary (M age=17 months). Children were presented with a novel word generalization task at each session. Additionally, the study examined the kinds of words the children learned early, based on parent reports, and the statistical regularities inherent in those vocabularies. The results indicate that as children learned nouns, they also learned to attend to shape in the novel word task. At the same time, children showed an acceleration in new noun production outside of the laboratory.