This article examines the phenomena of isolation and adaptation in the context of two recognition experiments investigating retroactive interference. Isolation is said to occur when memory for the contents of a passage resists retroactive interference from unrelated materials. Adaptation occurs when memory for the contents of a passage is subject to retroactive interference from thematically related materials. In Experiment 1, subjects first read either a prose passage or a list of sentences that lacked passage structure. Next, they rated similarities within a list of unconnected phrases. Although these phrases were not meaningfully related to the theme of the prose passage, they contained information that was conceptually similar to both types of previous sentences. In the subsequent forced-choice task, these interpolated phrases reliably influenced recognition of unstructured sentences only. Experiment 2 varied the thematic relevance of the interpolated phrases to the prose passage. Only theme-related phrases led to interference in passage recognition. The results from both experiments suggest a framework for predicting errors and accuracies in passage memory based on integrative processing.