The roles of basic reading processes and prior knowledge to comprehens
ion of expository text were addressed in a study of college readers. A
ccording to their performance in the Nelson-Denny Reading Comprehensio
n Text, 34 college students were divided into groups of above-average
and average readers and had to complete tasks of word and pseudoword v
ocalization, sentence verification, probe discourse memory, text-based
word recognition and word prediction. Subjects also took a prior know
ledge test, read an expository text, and answered comprehension questi
ons that covered explicit and implicit text information. The data indi
cated that word identification and propositional encoding measures wer
e closely related to individual differences in college-level reading c
omprehension ability. Examining the relative contributions of basic re
ading and prior knowledge to comprehension, it was shown that knowledg
e played the major role in answering explicit questions, whereas probe
discourse memory was relatively more important when the information w
as implicit.