Chasing the anchor: A systematic review and meta-analysis of perceptual anchoring deficits in developmental dyslexia

Purpose: We report the results of a systematic review and meta-analysis investigating the relationship between perceptual anchoring and dyslexia. Our goal was to assess the direction and degree of the effect between perceptual anchoring and reading ability in typical and atypical (i.e., dyslexic) readers. Method: We performed a literature search of experiments explicitly assessing perceptual anchoring and reading ability using PsycInfo (Ovid, 1860–2020), MEDLINE (Ovid, 1860–2019), EMBASE (Ovid, 1883–2019), and PubMed for all available years up to June (2020). Our eligibility criteria consisted of English language articles, and, at minimum, one experimental group identified as dyslexic—either by reading assessment at the time or by previous diagnosis. We assessed for risk of bias using an adapted version of the Newcastle–Ottawa Scale. Eight studies were included in this review and meta-analysis (n = 422 participants). Results: The overall effect was negative, moderate, and statistically significant; g = −0.70, 95% confidence interval [−1.10, −0.29]: a negative effect size indicating less perceptual anchoring in dyslexic versus nondyslexic groups. Visual assessment of funnel plot and Egger’s test suggest minimal bias but with significant heterogeneity; Q (7) = 17.03, prediction interval [−1.79, 0.40]. Conclusions: Of the included studies, we find evidence for a moderate perceptual anchoring deficit in individuals with dyslexia. The primary limitation of the current review is the small number of included studies. The variability of effect sizes appears consistent with the inherent variability within subtypes of dyslexia.