Effects of Practice on Font Legibility

Highway sign font legibility has been studied extensively over the past 50 years; however only limited research has been conducted on the range of fonts used for commercial signage. While earlier research has demonstrated that some of these fonts are more legible than others, difficulties have arisen in ascribing these differences to visual factors alone. The objective of this experiment was to determine if some of the font superiority effect is due to the level of font familiarity. Visual acuity thresholds for letter and words displayed in three fonts were recorded for a group of 72 younger and older subjects. The subjects read aloud two pages of text displayed in those fonts. Acuity thresholds for the three fonts were then reevaluated. The results showed that familiarity with a specific font significantly influences that font's legibility and that this effect was greater for older than younger subjects.