Should I Trust It When I Cannot See It? Credibility Assessment for Blind Web Users
Ali Abdolrahmani, Ravi Kuber · 2016 · Proceedings of the 18th International ACM SIGACCESS Conference on Computers and Accessibility (ASSETS '16) · doi:10.1145/2982142.2982173
Summary
This paper examines how blind screen reader users assess the credibility of web content compared to sighted users, revealing fundamental differences in credibility assessment strategies between the two groups. Web credibility — the believability of information and its source — is heavily influenced by visual appearance, which poses a challenge for blind users who cannot access these visual cues. The study recruited 11 legally blind participants (using JAWS or VoiceOver) and 11 sighted participants (ages 19-64, mean 36) for two tasks: browsing five pairs of web pages on topics including celebrity news, health, personal finance, and politics, rating each page's credibility on a 1-5 scale; and evaluating five sets of search engine results pages to select the most credible result for exploration. Pages were drawn from a validated Microsoft Research credibility dataset with expert ratings. Blind participants performed tasks remotely via video conferencing while sighted participants attended in person. Sessions were audio-recorded and analyzed alongside detailed observer notes and screen reader output logs.
Key findings
A statistically significant positive correlation was found between accessibility and perceived credibility for blind users (Spearman's rs = .3352, p = 0.0003), confirming that accessibility directly influences credibility judgments. Sighted participants rated credibility based primarily on visual aesthetics and layout ("design look" was the top factor in prior research), while blind participants focused heavily on textual content quality. Blind participants developed several non-visual credibility criteria: writing quality and sophistication of language; writing neutrality (distinguishing opinion from factual content); tone of writing (casual vs. professional); grammatical errors and typos (detected through changes in screen reader speech tone); presence of dates and statistics for scientific content; relevant links and citations; content meaningfulness and flow; information focus (whether content stayed on topic); and author credentials. Key browsing strategies included: avoiding extraneous content by skipping menus to reach main content; sequential line-by-line reading to avoid missing information; HTML element quick navigation (jumping between headings, links, landmarks); reading URLs character-by-character to verify domain legitimacy (e.g., ".org" considered more vetted); and searching for copyright symbols and author information. Accessibility barriers that negatively impacted credibility included: tables used for layout causing confusing navigation; slow-loading content making pages appear unfinished; unlabeled images and inaccessible media ("Should I trust it when I cannot see it?"); and inappropriate HTML tagging (e.g., using bold tags instead of heading tags). Blind participants reported higher confidence in their credibility ratings (4.36/5) than sighted participants (4.28/5), despite their ratings diverging more from expert assessments.
Relevance
This research reveals a critical and underexplored dimension of web accessibility: inaccessible design does not merely inconvenience blind users — it actively undermines their ability to make informed trust decisions about web content. For accessibility practitioners, this has direct security and safety implications: a blind user who cannot assess whether a site is legitimate may be more vulnerable to misinformation, phishing, or unreliable health advice. The finding that blind users equate accessibility with credibility means that poorly coded sites face a double penalty — they are both harder to use and perceived as less trustworthy. The specific textual cues blind users rely on (writing quality, tone, grammar, citations, author credentials) provide actionable guidance for designing credible interfaces: proper semantic HTML, meaningful headings, clear and professional writing, complete alt text, fast loading, and proper attribution all serve both accessibility and credibility. The study also highlights that the widely cited Fogg credibility framework, which emphasizes visual design, is insufficient for non-visual users and needs expansion to account for content-driven credibility assessment.
Tags: blindness · screen reader · web accessibility · web design · usability · information access · user research · security