Cloze probability and completion norms for 498 sentences: behavioral and neural validation using event-related potentials.

Three decades after their publication, Bloom and Fischler's (1980) sentence completion norms continue to demonstrate widespread utility. The aim of the present study was to extend this contribution by expanding the existing database of high-constraint, high cloze probability sentences. Using the criteria established by Bloom and Fischler, we constructed 398 new sentences and presented these along with 100 sentences from their original list to be normed using a sample of 400 participants. Of the 498 sentences presented, 400 met criteria for high cloze probability-that is, .67 or higher probability of being completed by a specific single word. Of these, 321 sentences were from the new set and an additional 79 were from Bloom and Fischler's set. A high degree of correspondence was observed between responses obtained by Bloom and Fischler for their high-constraint set. A second experiment utilized an N400 event-related potential paradigm to provide further validation of the contextual constraint for the newly generated set. As expected, N400 amplitude was greater for sentences that violated contextual expectancy by ending in a word other than the newly established completion norm. Sentence completion norms are frequently used in cognitive research, and this larger database of high cloze probability sentences is expected to be of benefit to the research community for many years to come. The full set of stimuli and sentence completion norms from this study may be downloaded from http://brm.psychonomic-journals.org/content/supplemental.