Evidence for different visual processing strategy for non-face stimuli in developmental prosopagnosia

We assembled a test battery to investigate developmental prosopagnosia (DP), a neurodevelopmental syndrome resulting in severe face recognition difficulties. To screen for general cognitive deficits that could explain poor face test performance, participants completed a fluid reasoning task using abstract shapes. This initial screening showed that DPs (n = 21) were more accurate than neurotypical controls (n = 90) but significantly slower, suggesting speed-accuracy trade-off. To address this, we calculated the Balanced Integration Score and found no group differences, highlighting that DPs clearly adopted a different strategy from controls. DPs' longer response times (RT) on face tasks vs controls are commonly interpreted as evidence of impairment and of lengthy, atypical featural face processing. Our data suggest this interpretation may be unreliable since clear RT differences were also observed in two non-face tasks where DPs showed no accuracy impairment. Instead, slower RTs appear to reflect a strategy shift in DPs.