Abstract

Does the higher information density of variable width fonts support faster reading than can be obtained with fixed width spacing? We compared maximum reading speeds on a CRT using identical characters with serifs in three conditions of pitch: (1) fixed width (FW), each character centered in a constant horizontal space, (2) variable width (VW), characters occupying only the space required to eliminate overlap, and (3) modified variable width (MVW), average information density equated to that of the FW condition through the addition of interword microspace. We found that for large characters (~0.25-1.0° character height), subjects read fastest with VW pitch, slowest with MVW pitch, and at intermediate speeds with FW pitch. At this range of character sizes, overall compactness of the text line determined best performance, although the superiority of FW relative to MVW indicates that crowding in individual word recognition may have been present as well. For small characters (< ~0.25°), FW pitch provided the highest reading speeds, while for most observers, MVW yielded better performance than VW pitch. Crowding, then, probably determines reading speed close to the acuity limit, where adding intra- or interword space enhances performance.

© 1989 Optical Society of America