This study compares the effectiveness of three types of computer graphics display for computer-assisted instruction in (1) low level (boxed alphanumerics and schematics), (2) medium level (line drawings), and (3) high level (line drawings plus animations). Three groups of 30 enlisted personnel at the Engineering School and the Defense Mapping School, Fort Belvoir, Virginia, studied a computer-assisted instructional lesson on the psychophysiology of audition. Upon lesson completion, retention of four knowledge categories addressed in the CAI lesson were tested. Groups did not differ in their performance on the final retention tests or in lesson completion time. Findings indicate that the addition of more realistic and sophisticated graphics displays in a CAI lesson do not insure an increase in instructional effectiveness but point out the need to determine principles and guidelines for the use of graphics in computer-based training. (Author)