The Face Processing Deficit in Developmental Dyslexia: A Meta-Analysis

Many studies have investigated face processing abilities in developmental dyslexia (DD) while conflicting evidence of both impaired and intact face processing has been reported. A systematic meta-analysis was conducted on the topic of the face processing abilities of DD. A total of 15 studies (34 effect sizes) were identified, representing data from 311 individuals with DD and 336 typically developing controls. A random-effects robust variance estimation model was used to synthesise the data. The average weighted standardised mean difference (Hedges' g) was 0.51 (95% confidence interval [0.24, 0.79], p = 0.001). A moderate level of heterogeneity was found while no publication bias was found between study-level effect sizes. Explorative meta-regression analyses showed that age, gender, and task type were not significant moderating factors. The results indicate that individuals with DD have face processing deficits compared with controls, suggesting domain-general deficits in DD and part of shared cognitive mechanisms underlying face and word processing.