Older readers are disproportionately affected by other adverse factors in visual design, such as small text size.
"[6] Aspects of type design that affect legibility include "x-height, character shapes, stroke contrast, the size of its counters, serifs or lack thereof, and weight.
[citation needed] While readers may like or dislike fonts based on the familiarity of their appearance, they nevertheless achieve a comparable reading performance after a short period of familiarization with a new typeface, provided that the glyphs are equally clear and exhibit the essential features of the represented letter.
At low resolution, the additional spacing between letters required for the serifs seems to improve legibility, whereas otherwise they have a slightly adverse effect.
[5] Common measures to improve legibility at lowest resolution include the use of wide apertures/large open counters, large x-height, low stroke variability, big features, etc., while some improvements like ink traps[clarification needed] are specific to different presentation media.
Dyslexics and learners also seem to prefer less regularity between individual letterforms, especially further differentiating features in glyphs that are often just mirrored versions of other letters, as in the group b, d, p and q, since the human brain seems to have evolved to recognize (symmetrical) three-dimensional objects regardless of their orientation in space.
[23][24] While textbook versions perform better with inexperienced readers/learners, most experienced readers seem to be more comfortable with the traditional two-story print forms for a and g.[25][26]