Subjects rated how certain they were that each of 60 statements was true or false. The statements were sampled from areas of knowledge including politics, sports, and the arts, and were plausible but unlikely to be specifically known by most college students. Subjects gave ratings on three successive occasions at 2-week intervals. Embedded in the list were a critical set of statements that were either repeated across the sessions or were not repeated. For both true and false statements, there was a significant increase in the validity judgments for the repeated statements and no change in the validity judgments for the non-repeated statements. Frequency of occurrence is apparently a criterion used to establish the referential validity of plausible statements.
