Not so fast! Response times in the computerized Benton Face Recognition Test may not reflect face recognition ability

Disentangling developmental prosopagnosia: A scoping review of terms, tools and topics

The goal of this preregistered scoping review is to create an overview of the research on developmental prosopagnosia (DP). Through analysis of all empirical studies of DP in adults, we investigate 1) how DP is conceptualized and defined, 2) how individuals are classified with DP and 3) which aspects of DP are investigated in the literature. We reviewed 224 peer-reviewed studies of DP. Our analysis of the literature reveals that while DP is predominantly defined as a lifelong face recognition impairment in the absence of acquired brain injury and intellectual/cognitive problems, there is far from consensus on the specifics of the definition with some studies emphasizing e.g., deficits in face perception, discrimination and/or matching as core characteristics of DP. These differences in DP definitions is further reflected in the vast heterogeneity in classification procedures. Only about half of the included studies explicitly state how they classify individuals with DP, and these studies adopt 40 different assessment tools. The two most frequently studied aspects of DP are the role of holistic processing and the specificity of face processing, and alongside a substantial body of neuroimaging studies of DP, this paints a picture of a research field whose scientific interests and aims are rooted in cognitive neuropsychology and neuroscience. We argue that these roots - alongside the heterogeneity in DP definition and classification - may have limited the scope and interest of DP research unnecessarily, and we point to new avenues of research for the field.

Perceptual heterogeneity in developmental prosopagnosia is continuous, not categorical

Developmental prosopagnosia (DP) is associated with considerable perceptual heterogeneity, though the nature of this heterogeneity and whether there are discrete subgroups versus continuous deficits remains unclear. Bennetts et al. (2022) recently found that holistic versus featural processing deficits distinguished discrete DP subgroups, but their sample was relatively small (N = 37), and subgroups were defined using a single task. To characterize perceptual heterogeneity in DPs more comprehensively, we administered a broad face perception battery to a large sample of 109 DPs and 134 controls, including validated measures of face matching (Cambridge Face Perception Test - CFPT, Computerized Benton Facial Recognition Test, Same/Different Face Matching Task), holistic processing (Part-Whole Task), and feature processing (Georges Task and Part-Whole part trials). When examining face matching measures, DPs exhibited a similar distribution of performance as controls, though shifted towards impairment by an average of 1.4 SD. We next applied Bennetts (2022) hierarchical clustering approach and k-means clustering to the CFPT upright, inverted, and inversion index measures, similarly finding one group of DPs with poorer inverted face performance and another with a decreased face inversion effect (holistic processing). However, these subgroup differences failed to generalize to other measures of feature and holistic processing beyond the CFPT. We finally ran hierarchical and k-means cluster analyses on our larger battery of face matching, feature, and holistic processing measures. Results clearly showed subgroups with generally better versus worse performance across all measures, with the distinction between groups being somewhat arbitrary. Together, these findings support a continuous account of DP perceptual heterogeneity, with performance differing primarily across all aspects of face perception.

The neuropsychological evaluation of face identity recognition

Facial identity recognition (FIR) is arguably the ultimate form of recognition for the adult human brain. Even if the term prosopagnosia is reserved for exceptionally rare brain-damaged cases with a category-specific abrupt loss of FIR at adulthood, subjective and objective impairments or difficulties of FIR are common in the neuropsychological population. Here we provide a critical overview of the evaluation of FIR both for clinicians and researchers in neuropsychology. FIR impairments occur following many causes that should be identified objectively by both general and specific, behavioral and neural examinations. We refute the commonly used dissociation between perceptual and memory deficits/tests for FIR, since even a task involving the discrimination of unfamiliar face images presented side-by-side relies on cortical memories of faces in the right-lateralized ventral occipito-temporal cortex. Another frequently encountered confusion is between specific deficits of the FIR function and a more general impairment of semantic memory (of people), the latter being most often encountered following anterior temporal lobe damage. Many computerized tests aimed at evaluating FIR have appeared over the last two decades, as reviewed here. However, despite undeniable strengths, they often suffer from ecological limitations, difficulties of instruction, as well as a lack of consideration for processing speed and qualitative information. Taking into account these issues, a recently developed behavioral test with natural images manipulating face familiarity, stimulus inversion, and correct response times as a key variable appears promising. The measurement of electroencephalographic (EEG) activity in the frequency domain from fast periodic visual stimulation also appears as a particularly promising tool to complete and enhance the neuropsychological assessment of FIR.

A new way of classifying developmental prosopagnosia: Balanced Integration Score

Despite severe everyday problems recognising faces, some individuals with developmental prosopagnosia (DP) can achieve typical accuracy scores on laboratory face recognition tests. To address this, studies sometimes also examine response times (RTs), which tend to be longer in DPs relative to control participants. In the present study, 24 potential (according to self-report) DPs and 110 age-matched controls completed the Cambridge Face and Bicycle Memory Tests, old new faces task, and a famous faces test. We used accuracy and the Balanced Integration Score (BIS), a measure that adjusts accuracy for RTs, to classify our sample at the group and individual levels. Subjective face recognition ability was assessed using the PI20 questionnaire and semi structured interviews. Fifteen DPs showed a major impairment using BIS compared with only five using accuracy alone. Logistic regression showed that a model incorporating the BIS measures was the most sensitive for classifying DP and showed highest area under the curve (AUC). Furthermore, larger between-group effect sizes were observed for a derived global (averaged) memory measure calculated using BIS versus accuracy alone. BIS is thus an extremely sensitive novel measure for attenuating speed-accuracy trade-offs that can otherwise mask impairment measured only by accuracy in DP.