The purpose of this study was to examine the effects of verbal and perceptual aspects of learner aptitude, in relation to inspection behaviors performed while learning from written materials containing two modes of instructional content. Science instructional materials containing both text and diagrams were modified by (1) inserting questions that asked for information from the text or from the diagrams, or (2) providing material without questions. The sample was formed of 185 subjects. Aptitude tests were given to all subjects. Pre- and post-test measures included performance on relevant diagram questions, incidental diagram questions, relevant text questions, and incidental text questions. The analysis of data revealed that inserted questions facilitated the acquisition of relevant information while exerting little influence upon the acquisition of incidental information. A positive relationship was also found between the number of inserted questions answered and the performance on relevant post-test questions. (Author/PS)