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Although it is generally assumed that face recognition relies on holistic processing, whether face recognition deficits observed in Developmental Prosopagnosics (DPs) can be explained by impaired holistic processing is currently under debate. The mixed findings from past studies could be the consequence of DP's heterogeneous deficit nature and the use of different measures of holistic processing—the inversion, part-whole, and composite tasks—which showed a poor association among each other. The present study aimed to gain further insight into the role of holistic processing in DPs. Groups of DPs and neurotypicals completed three tests measuring holistic face processing and non-face objects (i.e., Navon task). At a group level, DPs showed (1) diminished, but not absent, inversion and part-whole effects, (2) comparable magnitudes of the composite face effect and (3) global precedence effect in the Navon task. However, single-case analyses showed that these holistic processing deficits in DPs are heterogeneous. [ABSTRACT FROM AUTHOR]

Provoked overt recognition refers to the fact that patients with acquired prosopagnosia can sometimes recognize faces when presented in arrays of individuals from the same category (e.g., actors or politicians). We ask whether a prosopagnosic patient might experience recognition when presented with multiple different images of the same face simultaneously. Over two sessions, patient Herschel, a 66-year-old British man with acquired prosopagnosia, viewed face images individually or in arrays. On several occasions he failed to recognize single photos of an individual but successfully identified that person when the same photos were presented together. For example, Herschel failed to recognize any individual images of King Charles or Paul McCartney but recognised both in arrays of the same photos. Like reports based on category membership, overt recognition was transient and inconsistent. These findings are discussed in terms of models of covert recognition, alongside more recent research on within-person variability for face perception. [ABSTRACT FROM AUTHOR]

Subjects often look towards to previous location of a stimulus related to a task even when that stimulus is no longer visible. In this study we asked whether this effect would be preserved or reduced in subjects with developmental prosopagnosia. Participants learned faces presented in video-clips and then saw a brief montage of four faces, which was replaced by a screen with empty boxes, at which time they indicated whether the learned face had been present in the montage. Control subjects were more likely to look at the blank location where the learned face had appeared, on both hit and miss trials, though the effect was larger on hit trials. Prosopagnosic subjects showed a reduced effect, though still better on hit than on miss trials. We conclude that explicit accuracy and our implicit looking at nothing effect are parallel effects reflecting the strength of the neural activity underlying face recognition. [ABSTRACT FROM AUTHOR]

Most findings on prosopagnosia to date suggest preserved voice recognition in prosopagnosia (except in cases with bilateral lesions). Here we report a follow-up examination on M.T., suffering from acquired prosopagnosia following a large unilateral right-hemispheric lesion in frontal, parietal, and anterior temporal areas excluding core ventral occipitotemporal face areas. Twenty-three years after initial testing we reassessed face and object recognition skills [Henke, K., Schweinberger, S. R., Grigo, A., Klos, T., & Sommer, W. (1998). Specificity of face recognition: Recognition of exemplars of non-face objects in prosopagnosia. Cortex, 34(2), 289–296]; [Schweinberger, S. R., Klos, T., & Sommer, W. (1995). Covert face recognition in prosopagnosia – A dissociable function? Cortex, 31(3), 517–529] and additionally studied voice recognition. Confirming the persistence of deficits, M.T. exhibited substantial impairments in famous face recognition and memory for learned faces, but preserved face matching and object recognition skills. Critically, he showed substantially impaired voice recognition skills. These findings are congruent with the ideas that (i) prosopagnosia after right anterior temporal lesions can persist over long periods > 20 years, and that (ii) such lesions can be associated with both facial and vocal deficits in person recognition. [ABSTRACT FROM AUTHOR]

Response times (RTs) are commonly used to assess cognitive abilities, though it is unclear whether face processing RTs predict recognition ability beyond accuracy. In the current study, we examined accuracy and RT on a widely used face matching assessment modified to collect meaningful RT data, the computerized Benton Facial Recognition Test (BFRT-c), and measured whether RTs predicted face recognition ability and developmental prosopagnosia (DP) vs. control group membership. 62 controls and 36 DPs performed the BFRT-c as well as validated measures of face recognition ability: the Cambridge Face Memory Test (CFMT) and a Famous Faces Memory Test (FFMT). In controls, BFRT-c accuracy robustly predicted CFMT (r =.49, p <.001), FFMT (r =.43, p <.001), and a CFMT-FFMT composite (r =.54, p <.001), whereas BFRT-c RT was not significantly associated with these measures (all r's.21). We also found that BFRT-c accuracy significantly differed between DPs and controls, but RT failed to differentiate the groups. [ABSTRACT FROM AUTHOR]

Developmental prosopagnosia (DP) is a syndrome characterized by lifelong impairment in face recognition in the absence of brain damage. A key question regarding DP concerns which process(es) might be affected to selectively/disproportionally impair face recognition. We present evidence from a group of DPs, combining an overview of previous results with additional analyses important for understanding their pattern of preserved and impaired perceptual abilities. We argue that for most of these individuals, the common denominator is a deficit in (rapid) processing of global shape information. We conclude that the deficit in this group of DPs is not face-selective, but that it may appear so because faces are more visually similar—and recognized at a more fine-grained level—than objects. Indeed, when the demand on perceptual differentiation and visual similarity are held constant for faces and objects, we find no evidence for a disproportionate deficit for faces in this group of DPs. [ABSTRACT FROM AUTHOR]

Face-selective cortical areas that can be divided into a ventral stream and a dorsal stream. Previous findings indicate selective attention to particular aspects of faces have different effects on the two streams. To better understand the organization of the face network and whether deficits in attentional modulation contribute to developmental prosopagnosia (DP), we assessed the effect of selective attention to different face aspects across eight face-selective areas. Our results from normal participants found that ROIs in the ventral pathway (OFA, FFA) responded strongly when attention was directed to identity and expression, and ROIs in the dorsal pathway (pSTS-FA, IFG-FA) responded the most when attention was directed to facial expression. Response profiles generated by attention to different face aspects were comparable in DPs and normals. Our results demonstrate attentional modulation affects the ventral and dorsal steam face areas differently and indicate deficits in attentional modulation do not contribute to DP. [ABSTRACT FROM AUTHOR]

Typical face perception is mediated by holistic processing (i.e., the simultaneous integration of face parts into a whole representation). People with Acquired Prosopagnosia (AP), who have lost the ability to recognise faces after a brain lesion, should thus show atypical holistic coding. Our aim is to use the composite-face effect (CFE) as a measure of holistic processing in ST, a 48-year-old woman with AP but normal recognition of facial expressions of emotions, and matched healthy control participants. Two experiments examining the CFE for identity (Experiment 1) and for expression of emotions (Experiment 2) were conducted. Contrary to controls, in both experiments, ST showed an atypical (i.e., reversed) CFE, thus suggesting altered holistic mechanisms affecting both components of perceptual judgement. Results also suggest that normal facial expression recognition is achievable even with holistic processing difficulties, possibly through compensatory, part-based, mechanisms. [ABSTRACT FROM AUTHOR]

Individuals with developmental prosopagnosia (DP) sometimes experience object identification difficulties in addition to problems recognizing faces. To better understand the distribution of non-face object recognition ability in this population, we administered the Cambridge Car Memory Test (CCMT) – a leading, standardized measure of object recognition ability – to a large sample of DPs (N = 46). When considered as a single group, the DPs scored lower than matched controls. This finding provides further evidence that developmental object agnosia (DOA) may be more common in DP than in the general population. Relative to the DPs' face recognition deficits, however, car matching deficits were small and inconsistent. In fact, we observed a striking range of CCMT performance in our DP sample. While some DPs performed extremely poorly, many more achieved scores within one standard deviation of the typical mean, and several DP participants achieved excellent CCMT scores comparable with the best controls. [ABSTRACT FROM AUTHOR]

Whether face and object recognition are dissociated in prosopagnosia continues to be debated: a recent review highlighted deficiencies in prior studies regarding the evidence for such a dissociation. Our goal was to study cohorts with acquired and developmental prosopagnosia with a complementary battery of tests of object recognition that address prior limitations, as well as evaluating for residual effects of object expertise. We studied 15 subjects with acquired and 12 subjects with developmental prosopagnosia on three tests: the Old/New Tests, the Cambridge Bicycle Memory Test, and the Expertise-adjusted Test of Car Recognition. Most subjects with developmental prosopagnosia were normal on the Old/New Tests: for acquired prosopagnosia, subjects with occipitotemporal lesions often showed impairments while those with anterior temporal lesions did not. Ten subjects showed a putative classical dissociation between the Cambridge Face and Bicycle Memory Tests, seven of whom had normal reaction times. Both developmental and acquired groups showed reduced car recognition on the expertise-adjusted test, though residual effects of expertise were still evident. Two subjects with developmental prosopagnosia met criteria for normal object recognition across all tests. We conclude that strong evidence for intact object recognition can be found in a few subjects but the majority show deficits, particularly those with the acquired form. Both acquired and developmental forms show residual but reduced object expertise effects. [ABSTRACT FROM AUTHOR]

Visual crowding is a phenomenon that impairs object recognition when the features of an object are positioned too closely together. Crowding limits recognition in normal peripheral vision and it has been suggested to be the core deficit in visual agnosia, leading to a domain-general deficit in object recognition. Using a recently developed tool, we test whether crowding is the underlying deficit in four patients with category specific agnosias: Two with pure alexia and two with acquired prosopagnosia. We expected all patients to show abnormal crowding. We find that the two patients with acquired prosopagnosia show abnormal crowding effects in foveal vision, while the pure alexic patients do not, and that this constitutes a significant dissociation. Thus, abnormal crowding cannot explain all cases of visual agnosia. Much recent work has focused on similarities between pure alexia and acquired prosopagnosia. Here we show a difference in a basic visual mechanism—visual crowding. [ABSTRACT FROM AUTHOR]

Determining the familiarity and identity of a face have been considered as independent processes. Covert face recognition in cases of acquired prosopagnosia, as well as rapid detection of familiarity have been taken to support this view. We tested P.S. a well-described case of acquired prosopagnosia, and two healthy controls (her sister and daughter) in two saccadic reaction time (SRT) experiments. Stimuli depicted their family members and well-matched unfamiliar distractors in the context of binary gender, or familiarity decisions. Observers’ minimum SRTs were estimated with Bayesian approaches. For gender decisions, P.S. and her daughter achieved sufficient performance, but displayed different SRT distributions. For familiarity decisions, her daughter exhibited above chance level performance and minimum SRTs corresponding to those reported previously in healthy observers, while P.S. performed at chance. These findings extend previous observations, indicating that decisional space determines performance in both the intact and impaired face processing system. [ABSTRACT FROM AUTHOR]

Scientific research involves going beyond the well-trodden and well-tested ideas and theories that form the core of scientific knowledge. During the time scientists are working things out, some results will be right, and others will be wrong. Over time, the right results will emerge. Lisa Randall (Frank B. Baird, Jr. Professor of Science, Physics Department, Harvard University)We are grateful to all the commentators for the important and thoughtful comments raised in response to the Geskin and Behrmann (G & B) literature survey. The issues raised in the introduction to this Special Issue and in these commentaries not only address and challenge aspects of the G & B literature review, but contribute perspectives and extensions that go well beyond the scope of the review. As is evident from G & B and from the 13 commentaries, many aspects of congenital prosopagnosia (CP) remain controversial. Adopting the language of the quote above, the intention of the G & B survey, along with the commentaries and this response, is to establish a collaborative process from which the right results (and right theory) will emerge in time. We are grateful to the editor of this Special Issue, Dr. Brad Mahon, for his support and for facilitating this collaborative exchange in Cognitive Neuropsychology. [ABSTRACT FROM AUTHOR]

A longstanding controversy concerns the functional organization of high-level vision, and the extent to which the recognition of different classes of visual stimuli engages a single system or multiple independent systems. We examine this in the context of congenital prosopagnosia (CP), a neurodevelopmental disorder in which individuals, without a history of brain damage, are impaired at face recognition. This paper reviews all CP cases from 1976 to 2016, and explores the evidence for the association or dissociation of face and object recognition. Of the 238 CP cases with data permitting a satisfactory evaluation, 80.3% evinced an association between impaired face and object recognition whereas 19.7% evinced a dissociation. We evaluate the strength of the evidence and correlate the face and object recognition behaviour. We consider the implications for theories of functional organization of the visual system, and offer suggestions for further adjudication of the relationship between face and object recognition. [ABSTRACT FROM AUTHOR]

Cognitive neuropsychological evidence is widely viewed as inherently flawed or weak, despite well-reasoned arguments to the contrary by many theorists. Rather than attempting yet another defence of cognitive neuropsychology on logical grounds, we point out through examples that in practice, cognitive neuropsychological evidence is widely accepted as valid and important, and has had a major impact on cognitive theory and research. Objections offered in the abstract rarely arise in the context of actual studies. We develop these points through examples from the domain of vision, discussing cerebral achromatopsia and akinetopsia, selective impairment and sparing of face recognition, perception–action dissociations, and blindsight. [ABSTRACT FROM AUTHOR]

Face recognition abilities vary widely. While face recognition deficits have been reported in children, it is unclear whether superior face recognition skills can be encountered during development. This paper presents O.B., a 14-year-old female with extraordinary face recognition skills: a “super-recognizer” (SR). O.B. demonstrated exceptional face-processing skills across multiple tasks, with a level of performance that is comparable to adult SRs. Her superior abilities appear to be specific to face identity: She showed an exaggerated face inversion effect and her superior abilities did not extend to object processing or non-identity aspects of face recognition. Finally, an eye-movement task demonstrated that O.B. spent more time than controls examining the nose - a pattern previously reported in adult SRs. O.B. is therefore particularly skilled at extracting and using identity-specific facial cues, indicating that face and object recognition are dissociable during development, and that super recognition can be detected in adolescence. [ABSTRACT FROM AUTHOR]

The Cambridge Face Memory Test (CFMT) is widely accepted as providing a valid and reliable tool in diagnosing prosopagnosia (inability to recognize people’s faces). Previously, large-sample norms have been available only for Caucasian-face versions, suitable for diagnosis in Caucasian observers. These are invalid for observers of different races due to potentially severe other-race effects. Here, we provide large-sample norms (N = 306) for East Asian observers on an Asian-face version (CFMT–Chinese). We also demonstrate methodological suitability of the CFMT–Chinese for prosopagnosia diagnosis (high internal reliability, approximately normal distribution, norm-score range sufficiently far above chance). Additional findings were a female advantage on mean performance, plus a difference between participants living in the East (China) or the West (international students, second-generation children of immigrants), which we suggest might reflect personality differences associated with willingness to emigrate. Finally, we demonstrate suitability of the CFMT–Chinese for individual differences studies that use correlations within the normal range. [ABSTRACT FROM AUTHOR]

Anecdotal evidence suggests a relation between impaired spatial (navigational) processing and developmental prosopagnosia. To address this formally, we tested two aspects of topographic processing – that is, perception and memory of mountain landscapes shown from different viewpoints. Participants included nine individuals with developmental prosopagnosia and 18 matched controls. The group with developmental prosopagnosia had no difficulty with topographic perception, but was reliably poorer in the retention of topographic information. Additional testing revealed that this did not reflect a general deficit in visual processing or visual short-term memory. Interestingly, a classical dissociation could be demonstrated between impaired face memory and preserved topographic memory in two developmental prosopagnosics. We conclude that impairments in topographic memory tend to co-occur with developmental prosopagnosia, although the underlying functions are likely to be independent. [ABSTRACT FROM AUTHOR]

The “many-to-many” hypothesis proposes that visual object processing is supported by distributed circuits that overlap for different object categories. For faces and words the hypothesis posits that both posterior fusiform regions contribute to both face and visual word perception and predicts that unilateral lesions impairing one will affect the other. However, studies testing this hypothesis have produced mixed results. We evaluated visual word processing in subjects with developmental prosopagnosia, a condition linked to right posterior fusiform abnormalities. Ten developmental prosopagnosic subjects performed a word-length effect task and a task evaluating the recognition of word content across variations in text style, and the recognition of style across variations in word content. All subjects had normal word-length effects. One had prolonged sorting time for word recognition in handwritten stimuli. These results suggest that the deficit in developmental prosopagnosia is unlikely to affect visual word processing, contrary to predictions of the many-to-many hypothesis. [ABSTRACT FROM AUTHOR]

It has long been suggested that face recognition relies on specialized mechanisms that are not involved in visual recognition of other object categories, including those that require expert, fine-grained discrimination at the exemplar level such as written words. But according to the recently proposed many-to-many theory of object recognition (MTMT), visual recognition of faces and words are carried out by common mechanisms [Behrmann, M., & Plaut, D. C. (2013). Distributed circuits, not circumscribed centers, mediate visual recognition.Trends in Cognitive Sciences, 17,210–219]. MTMT acknowledges that face and word recognition are lateralized, but posits that the mechanisms that predominantly carry out face recognition still contribute to word recognition and vice versa. MTMT makes a key prediction, namely that acquired prosopagnosics should exhibit some measure of word recognition deficits. We tested this prediction by assessing written word recognition in five acquired prosopagnosic patients. Four patients had lesions limited to the right hemisphere while one had bilateral lesions with more pronounced lesions in the right hemisphere. The patients completed a total of seven word recognition tasks: two lexical decision tasks and five reading aloud tasks totalling more than 1200 trials. The performances of the four older patients (3 female, age range 50–64 years) were compared to those of 12 older controls (8 female, age range 56–66 years), while the performances of the younger prosopagnosic (male, 31 years) were compared to those of 14 younger controls (9 female, age range 20–33 years). We analysed all results at the single-patient level using Crawford'st-test. Across seven tasks, four prosopagnosics performed as quickly and accurately as controls. Our results demonstrate that acquired prosopagnosia can exist without word recognition deficits. These findings are inconsistent with a key prediction of MTMT. They instead support the hypothesis that face recognition is carried out by specialized mechanisms that do not contribute to recognition of written words. [ABSTRACT FROM AUTHOR]

Congenital prosopagnosia (CP), a lifelong impairment in face processing in the absence of brain damage, is often ascribed to impairment in holistic processing. It is still debated whether such difficulties are restricted to faces or whether they can also be observed for nonfacial stimuli. Here, we investigate this issue by examining CP individuals and their controls on two variations of the Garner speeded classification task tailored to assess holistic processing of nonfacial stimuli. In Experiment 1, participants were asked to judge the width of visually presented rectangles while ignoring their irrelevant height, or to judge changes in width while height remained constant. Critically, while controls exhibited the expected Garner interference, no such interference was observed for the CPs, indicating impaired holistic processing of integral, nonfacial shape dimensions. Experiment 2, utilized the same Garner paradigm, but here participants were asked to judge integral dimensions that are unrelated to shape (colour). Importantly, both CPs and controls exhibited the same level of Garner interference, indicating intact integral processing of colour dimensions. This dissociation between the performance on the two Garner tasks indicates that CPs do not exhibit a general local processing bias or impaired integration of any perceptual dimensions, but rather a deficit that is restricted to tasks requiring holistic integral perception of shape dimensions. Taken together, these results provide evidence for the existence of a general impairment in holistic shape perception in CP, which may be related to the mechanisms underlying this disorder. [ABSTRACT FROM AUTHOR]

Developmental prosopagnosia is characterized by a severe deficit in face-identity recognition. Most developmental prosopagnosics do not report deficits of facial age or gender perception. We developed tasks for evaluating facial age and gender processing and used them in the largest group of developmental prosopagnosics (N = 18) tested on facial age and gender perception. Care was taken to ensure that the tests were sufficiently sensitive to subtle deficits and required holistic processing as assessed by strong inversion effects in control subjects. Despite severe facial identity deficits, developmental prosopagnosics largely performed these discriminations comparably to controls. The common descriptor “faceblind” implied by the term prosopagnosia is inaccurate as certain kinds of nonidentity facial information, which we call physiognomic features, are processed well by both prosopagnosics and age-matched controls alike. Normal facial age and gender perception in developmental prosopagnosics is consistent with parallel processing models in the cognitive architecture of face processing. [ABSTRACT FROM AUTHOR]

The deficit in face recognition in individuals with prosopagnosia has often been attributed to an underlying impairment in holistic processing. Exactly what constitutes holistic processing has remained controversial, however. Here, we compare how configural information and featural information interact during face processing in a group of individuals with congenital prosopagnosia (CP) and matched controls. We adopted Amishav and Kimchi's version of Garner's speeded classification task, in which observers classify upright faces based on configural (intereyes and nose–mouth spacing) or featural (shape of eyes, nose, and mouth) information while the other dimension remains constant or varied randomly. We replicated the finding that normal observers evince symmetric Garner interference—failure to selectively attend to features without being influenced by irrelevant variation in configuration, and vice versa—indicating that featural and configural information are integral in normal face processing. In contrast, the CPs showed no Garner interference: They were able to attend to configural information without interference from irrelevant variation in featural information, and they were able to attend to featural information without interference from irrelevant variation in configural information. The absence of Garner interference in CP provides strong evidence that featural information and configural information are perceptually separable in CP's face processing. These findings indicate that CPs do not perceive faces holistically; rather, they process featural and configural information independently. [ABSTRACT FROM AUTHOR]

Because holistic processing is a hallmark of normal face recognition, we ask whether such processing is reduced in developmental prosopagnosia (DP), and, if so, what the sources are of this deficit. Existing literature provides a mixed picture, with face inversion effects showing consistent holistic processing deficits but unable to locate their source and with some composite face studies showing reduced holistic processing and some not. We addressed this issue more thoroughly with a very large sample of DPs (N= 38) performing the part–whole task, a well-accepted measure of holistic processing that allows for the separate evaluation of individual face parts. Contrary to an expected overall reduction in holistic processing, we found an intact holistic advantage for the mouth and a complete absence of a holistic advantage for the eye region. Less severely impaired prosopagnosics showed significantly more holistic processing of the mouth, suggesting that holistic processing can aid them in recognizing faces. [ABSTRACT FROM AUTHOR]

Developmental prosopagnosia (DP) is defined by severe face recognition problems resulting from a failure to develop the necessary visual mechanisms for processing faces. While there is a growing literature on DP in adults, little has been done to study this disorder in children. The profound impact of abnormal face perception on social functioning and the general lack of awareness of childhood DP can result in severe social and psychological consequences for children. This review discusses possible aetiologies of DP and summarizes the few cases of childhood DP that have been reported. It also outlines key objectives for the growth of this emerging research area and special considerations for studying DP in children. With clear goals and concerted efforts, the study of DP in childhood will be an exciting avenue for enhancing our understanding of normal and abnormal face perception for all age groups. [ABSTRACT FROM AUTHOR]

The author gives an anecdotal account of his life with developmental prosopagnosia (DP). He was not formally diagnosed until the age of 53 and has evolved a complicated strategy for recognizing people based on non-facial physical features and context. He describes his experiences through infancy, school, university life and courtship, work and family life. He believes that he has lived a full and successful life despite DP but that some aspects of his social and work life were impaired by face-blindness. In his experience people react positively and helpfully if the consequences of DP are explained to them, and this improves social interactions and communications. [ABSTRACT FROM AUTHOR]

This study addresses two central and controversial issues in developmental prosopagnosia (DP), configuration- versus feature-based face processing and the influence of affective information from either facial or bodily expressions on face recognition. A sample of 10 DPs and 10 controls were tested with a previously developed face and object recognition and memory battery (Facial Expressive Action Stimulus Test, FEAST), a task measuring the influence of emotional faces and bodies on face identity matching (Face–Body Compound task), and an emotionally expressive face memory task (Emotional Face Memory task, FaMe-E). We show that DPs were impaired in upright, but not inverted, face matching but they performed at the level of controls on part-to-whole matching. Second, DPs showed impaired memory for both neutral and emotional faces and scored within the normal range on the Face–Body Compound task. Third, configural perception but not feature-based processing was significantly associated with memory performance. Taken together the results indicate that DPs have a deficit in configural processing at the perception stage that may underlie the memory impairment. [ABSTRACT FROM AUTHOR]

People with developmental prosopagnosia (DP) show severe face-recognition deficits that typically emerge during childhood without history of neurological damage. We review findings from recent event-related brain potential (ERP) studies of face perception and face recognition in DP. The generic face-sensitivity of the N170 component is present in most DPs, suggesting rapid category-selective streaming of facial information. In contrast, DPs show atypical N170 face inversion effects, indicative of impaired structural encoding, specifically for upright faces. In line with neurodevelopmental accounts of DP, these effects are similar to those observed for other developmental disorders, as well as for younger children and older adults. Identity-sensitive ERP components (N250, P600f) triggered during successful face recognition are similar for DPs and control participants, indicating that the same mechanisms are active in both groups. The presence of covert face-recognition effects for the N250 component suggests that visual face memory and semantic memory can become disconnected in some individuals with DP. The implications of these results for neuropsychological and neurodevelopmental perspectives on DP are discussed. [ABSTRACT FROM AUTHOR]

We present a new case of acquired prosopagnosia resulting from extensive lesions predominantly in the right occipitotemporal cortex. Functional brain imaging revealed atypical activation of all core face areas in the right hemisphere, with reduced signal difference between faces and objects compared to controls. In contrast, Herschel's lateral occipital complex showed normal activation to objects. Behaviourally, Herschel is severely impaired with the recognition of familiar faces, discrimination between unfamiliar identities, and the perception of facial expression and gender. Notably, his visual recognition deficits are largely restricted to faces, suggesting that the damaged mechanisms are face-specific. He showed normal recognition memory for a wide variety of object classes in several paradigms, normal ability to discriminate between highly similar items within a novel object category, and intact ability to name basic objects (except four-legged animals). Furthermore, Herschel displayed a normal face composite effect and typical global advantage and global interference effects in the Navon task, suggesting spared integration of both face and nonface information. Nevertheless, he failed visual closure tests requiring recognition of basic objects from degraded images. This abnormality in basic object recognition is at odds with his spared within-class recognition and presents a challenge to hierarchical models of object perception. [ABSTRACT FROM PUBLISHER]