Holistic face perception is impaired in developmental prosopagnosia

Abstract

Individuals with developmental prosopagnosia (DP) have severe difficulties recognising familiar faces. A current debate is whether these face recognition impairments derive from problems with face perception and in particular whether individuals with DP cannot utilize holistic representations of individual faces. To assess this hypothesis, we recorded event-related potentials (ERPs) during a sequential face identity matching task where successively presented pairs of upright faces were either identical or differed with respect to their internal features, their external features, or both. Participants with DP and age-matched controls reported on each trial whether the face pair was identical or different. To track the activation of cortical visual face memory representations, we measured N250r components over posterior face-selective regions. N250r components to full face repetitions were strongly attenuated for DPs as compared to control participants, indicating impaired face identity matching processes in DP. In the Control group, the N250r to full face repetitions was superadditive (i.e., larger than the sum of the two N250r components to partial repetitions of external or internal features). This demonstrates that holistic face representations were involved in identity matching processes. In the DP group, N250r components to full and partial identity repetitions were strictly additive, indicating that the identity matching of external and internal features operated in an entirely part-based fashion, without any involvement of holistic representations. In line with this conclusion, DPs also made a disproportionate number of errors on partial repetition trials, where they often failed to report a change of internal facial features. This suggests an atypical strategy for encoding external features as cues to identity in DP. These results provide direct electrophysiological and behavioural evidence for qualitative differences in the representation of face identity in the occipital-temporal face processing system in developmental prosopagnosia.

Objective Patterns of Face Recognition Deficits in 165 Adults with Self-Reported Developmental Prosopagnosia

“…On the one hand, the low prevalence of mnemonic cases reported here fits well with the recent work of Biotti and colleagues [36], who used group analyses to suggest a widespread overlap between impaired face perception and unfamiliar face memory in DP—a finding that is also supported by our PCA. Together, these findings suggest that the CFPT and CFMT tap similar processes, and that unfamiliar face memory impairments in DP are mostly (but not always) underpinned by at least some weakness in face perception (affecting the encoding of faces; see also [19]). However, it is likely that this widespread weakness in face perception may not exceed diagnostic cut-offs in many cases (31 of the 63 DPs who met existing diagnostic criteria in this study did not achieve impaired scores on the CFPT).…”

“…These tests were later supplemented with standardized tests of unfamiliar face memory (e.g., using the Recognition Memory Test for Faces: [16]) or perception (e.g., using the Benton Facial Recognition Test: [17]). While famous face tests remain popular for the assessment of DP (e.g., [18,19]), bespoke tests of personally familiar face recognition are labour-intensive to prepare for the typically larger samples of developmental compared to acquired cases, and it is also difficult to collect well-matched control data. Further, both the Warrington and Benton tests have been subject to some criticism, as successful recognition performance can be achieved using extra-facial cues alone (e.g., the hairline or clothing: [20]).…”

Diagnosing developmental prosopagnosia: repeat assessment using the Cambridge Face Memory Test

“…That is, the reason that no practice effect emerged in the noise section for faces is that the addition of noise removes featural information and forces a reliance on holistic processing [ 72 ]. Because our participants all self-reported with face recognition difficulties, it follows that the addition of noise prohibits the use of feature-by-feature compensatory strategies, and exacerbates difficulties in those individuals that struggle with the holistic processing of faces [ 73 – 75 ]. In contrast, because holistic processing is not thought to benefit the recognition of objects such as cars [ 76 – 78 ], the addition of noise to these stimuli is not so detrimental in our population.…”

System for Face Recognition under Different Facial Expressions Using a New Associative Hybrid Model Amαβ-KNN for People with Visual Impairment or Prosopagnosia

“…The recognition of faces is a process that is naturally performed by human beings from their earliest years, it is a tool for survival and evolution because it allows the recognition of other people and the use of memories about those; unfortunately, for people who suffer from visual disability or prosopagnosia [24] the process of face recognition is complicated, since they are unable to identify by visual means a known or unknown person, hence the importance of proposing a device that performs the process automatically and tells the user the identification of the person in front of them. For this it is important to consider that the natural process performed by humans is complex and robust, since it is necessary to extract, analyse, discriminate, and classify a set of data provided by the sense of sight.…”