Abstract
Apperceptive and associative acquired prosopagnosia (AP) subtypes have often been reported, but it has been challenging to apply this distinction to developmental prosopagnosia (DP). One reason is that methods of categorizing perceptually impaired DPs have been insufficient, e.g., using single tests for classification. In this study, we compared accuracy performance between 30 DPs and 30 age-matched controls on a battery of four valid/reliable face matching tests: Benton Face Recognition Test, USC Face Perception Test, Telling Faces Together test, and Cambridge Face Perception Test. Using DSM-5 cutoffs for mild neurocognitive impairment, DPs >1SD below the mean on two or more of the above tests were classified as perceptually impaired (16/30 DPs), while the remainder (14/30) were classified as perceptually unimpaired. To see if there were meaningful differences between these DP sub-groups, we further assessed performance on face tasks that measured feature and configural processing. On the Georges face-matching task, DPs with perceptual impairment showed significantly reduced performance for identifying changes in the upper half of the face (eye position and forehead height) but not in the lower half of the face (mouth size and chin). In the part-whole test, perceptually impaired DPs showed significantly worse performance on eyes trials while performing similarly on the mouth and nose trials. Thus, similar to apperceptive APs, perceptually impaired DPs had particular impairments with processing the eye region. Poorer performance in perceptually-impaired DPs was also observed on the CFMT and face familiarity parameter on the Old/New task, overall suggesting that perceptually-impaired DPs are also worse at face recognition and that this may be driven by a lack of ‘feeling of knowing’ that is relatively intact in perceptually unimpaired DPs. Our study provides a novel, theoretically-grounded approach to identifying perceptually impaired DPs and provides evidence of important mechanistic differences that are consistent with the AP literature.