When some items on a list are strengthened by extra study time or repetitions, recognition of other, unrelated, list items is not harmed (Ratdiff, Clark, and Shiffrin, in press). Shiffrin, Ratcliff, and Clark (in press) accounted for this negative list-strength finding with a model assuming that different items are stored separately in memory, but that repetitions are accumulated together into a single stronger memory trace. If so, repeating words in the context of different sentences might cause separate storage of the repetitions of a given word, because either word or sentence traces are stored separately. Such a result should produce a positive list-strength effect. In Experiment 1 this result was produced for single word recognition and for two types of sentence recognition. In Experiment 2, both words and sentences were repeated together largely eliminating the list-strength effect. A sentence trace model was fit to the data supporting the account of Shiffrin et al. (in press) and validating an account of word and sentence recognition in which activation is summed for representations of all list items.