Presents four experiments comparing the perceptual span in second-, fourth-, and sixth-grade readers and skilled adult readers. Suggests that the size of perceptual span is variable and influenced by text difficulty. Concludes that the size of perceptual span does not cause slow reading rates in beginning readers. (Author/DR)

Discusses text displayed on computer screens and examines the effects of three layout variables--justification, line length, and leading--on reading speed and comprehension. Current literature on each variable is reviewed, and implications for the design of computer-based instruction are presented. (Author/LRW)