There are three unique cognitive mechanisms during note taking: generative processing, summarization, and sustained attention. Generative processing is active construction of associations between novel information and prior knowledge and experiences. Summarization forces identification of the most pertinent information to create a coherent synopsis. Sustained attention is selectively concentrating on novel information while ignoring irrelevant distraction. This investigation compared the operation of the three cognitive mechanisms in relation to the note-taking effect—the advantage of note taking when there is no opportunity to review the notes. Experiment 1, through measurement of task-relevant and task-irrelevant distraction, showed that sustained attention is positively related and generative processing negatively related to retention. Experiment 2, through an instruction manipulation, showed that generative processing impeded and summarization facilitated retention. Therefore, generative processing cannot account for the note-taking effect. Instead, these results suggest that summarization and sustained attention are the primary cognitive processes underlying the note-taking effect.