The effect of typeface and font size on reading text on a tablet computer for older and younger people
Maneerut Chatrangsan, Helen Petrie · 2019 · Proceedings of the 16th International Web for All Conference (W4A) · doi:10.1145/3315002.3317568
Summary
This study investigated how typeface (serif vs. sans serif) and font size (14, 16, and 18 point) affect reading performance and preferences on tablet computers for younger and older people. The research was conducted cross-culturally in both Thailand and the UK, with participants reading in Thai and English respectively. In the UK, 54 participants took part (36 older adults aged 62-84, mean 69.4 years; 18 younger adults aged 18-23, mean 19.2 years). In Thailand, 36 participants took part (18 older adults aged 61-74, mean 66.0 years; 18 younger adults aged 19-23, mean 20.8 years). All participants used a 4th-generation iPad running Safari. The English typefaces were Times New Roman (serif) and Arial (sans serif); the Thai typefaces were TH Sarabun (serif, the official Thai document font) and Kanit (sans serif). Each participant skim-read six short texts (228-233 words, fitting on a single tablet screen without scrolling) in different typeface and font size combinations, then answered three multiple-choice comprehension questions per text. The study used a mixed experimental design with typeface and font size as within-participant variables and age group as a between-participant variable. Reading time, comprehension accuracy, and subjective ratings of ease and fatigue were measured.
Key findings
In both countries, font size significantly affected reading time but typeface did not. The 18-point text was read significantly faster than 14 or 16 point in both the UK (p < .001) and Thailand (p < .005), with no significant difference between 14 and 16 point. Older participants read significantly more slowly than younger participants in both countries (UK: 68.6 vs 51.5 seconds; Thailand: 146.2 vs 88.8 seconds), but age did not interact with typeface or font size effects on reading time. Comprehension was significantly better with serif typefaces in both countries (median 6.0 vs 5.0 correct in UK; 6.0 vs 4.0 in Thailand) and improved with larger font sizes. A notable cross-cultural difference emerged in subjective preferences: UK participants found sans serif easier and less tiring to read, with older UK participants overwhelmingly preferring 18pt sans serif (55.6% chose this combination; 86.1% of all older UK choices were sans serif). Thai participants showed the opposite pattern, rating serif easier and less tiring, with 94.0% of older Thai participants choosing 18pt serif and 100% of all older Thai choices being serif. Despite these preference differences, the objective comprehension advantage for serif typefaces was consistent across both countries. In both countries, older participants showed a clear preference for 18pt text while younger participants showed no definitive size preference.
Relevance
This research provides evidence-based guidance for accessible text presentation on tablets that is directly actionable for web developers and designers. The clearest practical recommendation is to use at least 18-point font size for body text on tablet devices — this size was fastest to read, yielded better comprehension, was rated easiest and least tiring, and was strongly preferred by older adults in both cultures. This finding challenges the common web practice of using smaller text sizes (often 14-16px base sizes) and supports the WCAG guideline for text resizing. The comprehension advantage for serif typefaces in both languages is notable, though it contrasts with the common web design convention of using sans serif fonts for screen text. The cross-cultural differences in typeface preference (sans serif preferred in the UK, serif in Thailand) caution against applying Western typography research universally and highlight the importance of cultural context in accessible design. For organizations serving international or multilingual audiences, the findings suggest that typography defaults should be culturally informed rather than one-size-fits-all. The lack of interaction between age and typographic variables is reassuring — it suggests that optimizing text presentation for older readers (larger sizes, appropriate typefaces) does not disadvantage younger readers.
Tags: readability · typography · font size · older adults · aging · tablet computers · cross-cultural · visual accessibility · text presentation