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Developmental Prosopagnosia. A Single Case Report
Abstract
A patient with prosopagnosia is described. It is suggested that the deficit in this case is primarily apperceptive, and possible associated symptoms were investigated. The fact that the patient did not present initially as brain damaged is discussed.
... Congenital prosopagnosia (CP), also known as developmental prosopagnosia or hereditary prosopagnosia (OMIM 610382), was rst reported in 1976 (McConachie 1976) and is a selective impairment of visual learning and recognition of faces, in the absence of any detectable neurological injuries (McConachie 1976;Damasio et al. 1990;Nunn et al. 2001;Kress and Daum 2003;Behrmann and Avidan 2005;Duchaine and Nakayama 2006b;Gruter et al. 2008;Susilo and Duchaine 2013). Both a questionnaire-based screening method (Kennerknecht et al. 2006Kennerknecht, Ho et al. 2008;Kennerknecht 2021) and behavioral tests (Bowles et al. 2009) have estimated the prevalence of CP at 1.8-2.9% in the general population, providing a global estimate of tens of millions of CP individuals (CPs). ...
... Congenital prosopagnosia (CP), also known as developmental prosopagnosia or hereditary prosopagnosia (OMIM 610382), was rst reported in 1976 (McConachie 1976) and is a selective impairment of visual learning and recognition of faces, in the absence of any detectable neurological injuries (McConachie 1976;Damasio et al. 1990;Nunn et al. 2001;Kress and Daum 2003;Behrmann and Avidan 2005;Duchaine and Nakayama 2006b;Gruter et al. 2008;Susilo and Duchaine 2013). Both a questionnaire-based screening method (Kennerknecht et al. 2006Kennerknecht, Ho et al. 2008;Kennerknecht 2021) and behavioral tests (Bowles et al. 2009) have estimated the prevalence of CP at 1.8-2.9% in the general population, providing a global estimate of tens of millions of CP individuals (CPs). ...
... Both a questionnaire-based screening method (Kennerknecht et al. 2006Kennerknecht, Ho et al. 2008;Kennerknecht 2021) and behavioral tests (Bowles et al. 2009) have estimated the prevalence of CP at 1.8-2.9% in the general population, providing a global estimate of tens of millions of CP individuals (CPs). Familial studies (McConachie 1976;De Haan 1999;Galaburda and Duchaine 2003;Dobel et al. 2007;Duchaine et al. 2007;Grueter et al. 2007;Kennerknecht et al. 2006Kennerknecht et al. , 2007Kennerknecht, Pluempe et al. 2008;Schmalzl et al. 2008;Lee et al. 2010;Johnen et al. 2014) and twin studies (Polk et al. 2007;McKone and Palermo 2010;Wilmer et al. 2010;Zhu et al. 2010) suggest that CP and face recognition abilities are highly heritable. In pedigree analysis, a simple autosomal dominant mode of inheritance has been observed (De Haan 1999;Kennerknecht et al. 2006;Duchaine et al. 2007;Grueter et al. 2007;Schmalzl et al. 2008;Lee et al. 2010), indicating that mutations in a single gene can lead to face recognition defects. ...
Face recognition is important for both visual and social cognition. While prosopagnosia or face blindness has been known for seven decades and face specific neurons for half a century, the molecular genetic mechanism is not clear. Here we report results after 17 years of research with classic genetics and modern genomics. From a large family with 18 congenital prosopagnosia (CP) members with obvious difficulties in face recognition in daily life, we uncovered a fully cosegregating private mutation in the MCTP2 gene which encodes a calcium binding transmembrane protein expressed in the brain. After screening through cohorts of 6589, we found more CPs and their families, allowing detection of more CP associated mutations in MCTP2. Face recognition differences were detected between 14 carriers with the frameshift mutation S80fs in MCTP2 and 19 non-carrying volunteers. 6 families including one with 10 members showed the S80fs-CP correlation. Functional magnetic resonance imaging found association of impaired recognition of individual faces by MCTP2 mutant CPs with reduced repetition suppression to repeated facial identities in the right fusiform face area. Our results have revealed genetic predisposition of MCTP2 mutations in CP, 76 years after the initial report of prosopagnosia and 47 years after the report of the first CP. This is the first time a gene required for a higher form of visual social cognition was found in humans.
... However, when the head orientation deviates from straight ahead, this strategy is no longer available (Balsdon & Clifford, 2017;Otsuka, Mareschal, Calder, & Clifford, 2014). Some studies with prosopagnosic patients used stimuli with frontal head orientation (Duchaine et al., 2009;Burra et al., 2017), while others used stimuli with deviated head orientation (De Haan & Campbell, 1991;McConachie, 1976;Perrett et al., 1988) and differences between studies may arise from 107 ERNI, MAURER, KERZEL, & BURRA differences in task difficulty caused by head orientation. ...
... Furthermore, we included deviated head orientations that require integration of head and gaze cues (Langton, Watt, & Bruce, 2000). In past studies, deficits in gaze perception were more clearly visible with deviated head orientation than with frontal face images (De Haan & Campbell, 1991;McConachie, 1976;Perrett et al., 1988). ...
... However, when gaze direction was more difficult to distinguish (gaze directed to the upper-left, upper-right, lower-left, and lower-right), the perception of gaze direction with frontal or deviated head orientation was impaired compared to a matched control group. These results imply that task demands are critical to observe a deficit in PS, which is consistent with previous work on other populations (De Haan & Campbell, 1991;McConachie, 1976;Perrett et al., 1988). In other words, the results suggest that abnormal processing of gaze direction only occurs when variations of gaze direction were subtle (upper-left, upper-right, lowerleft, lower-right), unlike in previous studies were gaze direction was easy to distinguish (leftward, rightward, upward and downward) (Burra et al., 2017;Duchaine et al., 2009). ...
The ability to perceive the direction of eye gaze is critical in social settings. Brain lesions in the superior temporal sulcus (STS) impair this ability. We investigated the perception of gaze direction of PS, a patient suffering from acquired prosopagnosia (Rossion et al., 2003). Despite lesions in the face network, the STS was spared in PS. We assessed perception of gaze direction in PS with upright, inverted, and contrast-reversed faces. Compared to the performance of 11 healthy women matched for age and education, PS demonstrated abnormal discrimination of gaze direction with upright and contrast-reversed faces, but not with inverted faces. Our findings suggest that the inability of the patient to process faces holistically weakened her perception of gaze direction, especially in demanding tasks.
... Even though several hundred cases of DP have been reported since its original description by McConachie in 1976 [6], there is still debate concerning which cognitive processes are impaired in DP and whether the disorder is even selective for faces [7]. In 2016, we reported findings from a small sample of DPs (N = 10) where we focused on examining their object recognition abilities [8]. ...
... While several hundred cases with developmental prosopagnosia (DP) have been reported over the years since its initial description by McConachie [6], it is still not clear what kind of cognitive dysfunction(s) is underlying the disorder or whether it is the same for all cases with DP. Further, in the cases where seemingly selective impairments for faces have been observed, it has not been examined whether differences in visual similarity between the domains could account for the selectivity [11]. ...
It is still a matter of debate whether developmental prosopagnosia is a disorder selective to faces or whether object recognition is also affected. In a previous study, based on a small sample of developmental prosopagnosics (DPs; N = 10), we found impairments in both domains although the difficulties were most pronounced for faces. Importantly, impairments with faces and objects were systematically related. We suggested that that the seemingly disproportional impairment for faces in DP was likely to reflect differences between stimulus categories in visual similarity. Here, we aimed to replicate these findings in a larger, independent sample of DPs (N = 21) using the same experimental paradigms. Contrary to our previous results, we found no disproportional effect of visual similarity on performance with faces or objects in the new DP group when compared to controls (N = 21). The new DP group performed within the control range, and significantly better than the old DP-group, on sensitive and demanding object recognition tasks, and we can demonstrate a classical dissociation between face and object recognition at the group level. These findings are perhaps the strongest evidence yet presented for a face-specific deficit in developmental prosopagnosia.
... Prosopagnosia following brain injury or disease (acquired prosopagnosia) is quite a rare condition, and until recently, it was thought that this was also the case for the developmental deficit in face recognition referred to as developmental prosopagnosia. Developmental prosopagnosia was first described in 1976 by McConachie (McConachie, 1976), and the last 10-15 years has seen a surge in interest in this condition, which is estimated to be more common than originally thought. Some authors argue that this "mere deficit" in face recognition should not be compared to the severe problems observed in acquired prosopagnosia, and that the term "prosopdysgnosia" should be used instead (Rossion, 2018b); others debate whether developmental or congenital prosopagnosia is the best referent. ...
... It occurs in the absence of neurological illness or injury, sensory deficits or general intellectual impairment, and conventional structural imaging is normal. McConachie (1976) reported the first modern case of developmental prosopagnosia. For the next 30 years or so this condition was thought to be very rare: a review from 2003 found only 9 published cases with developmental prosopagnosia from 1976-2002 (Kress and Daum, 2003). ...
Prosopagosia is an impairment in face identity recognition affecting both the memory for familiar faces and the ability to learn new faces. Prosopagnosia exists in a relatively pure form following focal brain injury to right or bilateral occipito-temporal cortex, but can also be a symptom of more diffuse or distributed damage. The type of prosopagnosia may differ depending on the lesion site, and the dominant impairment may be in perception or memory. Prosopagnosia also exists in a developmental form, where the ability to learn and recognize others' faces does not develop normally. The cause and underlying cerebral substrate of this developmental type is not known.
... This is because the evidence base was too weak, or absent, to review. For example, people with developmental prosopagnosia suffer lifelong difficulties recognising faces ( (Burns et al., 2023;McConachie, 1976) Burns et al., 2023McConachie, 1974). Studies into this group have yielded minimal cognitive strengths using the Navon task, reading and self-reports, although many of these have been contradicted upon replication (Behrmann et al., 2005;Bennetts et al., 2022;Burns and Bukach, 2021;Duchaine et al., 2007;Svart and Starrfelt, 2022). ...
Neurodevelopmental disorders are traditionally characterised by a range of associated cognitive impairments in, for example, sensory processing, facial recognition, visual imagery, attention, and coordination. In this critical review, we propose a major reframing, highlighting the variety of unique cognitive strengths that people with neurodevelopmental differences can exhibit. These include enhanced visual perception, strong spatial, auditory, and semantic memory, superior empathy and theory of mind, along with higher levels of divergent thinking. Whilst we acknowledge the heterogeneity of cognitive profiles in neurodevelopmental conditions, we present a more encouraging and affirmative perspective of these groups, contrasting with the predominant, deficit-based position prevalent throughout both cognitive and neuropsychological research. In addition, we provide a theoretical basis and rationale for these cognitive strengths, arguing for the critical role of hereditability, behavioural adaptation, neuronal-recycling, and we draw on psychopharmacological and social explanations. We present a table of potential strengths across conditions and invite researchers to systematically investigate these in their future work. This should help reduce the stigma around neurodiversity, instead promoting greater social inclusion and significant societal benefits.
... Apperceptive prosopagnosia is linked to the posterior occipito-temporal region while associative prosopagnosia is linked to the anterior temporo-occipital region. 16 Patients can also be classified etiologically as having developmental (congenital) prosopagnosia, [17][18][19] in which difficulty with or loss of facial recognition occurs at the time of birth or in very early childhood, in the absence of a history of brain injury or identifying lesion. 20 Developmental prosopagnosia can be of the A C C E P T E D M A N U S C R I P T apperceptive type or the associative type. ...
Loss of facial recognition or prosopagnosia has been well-recognized for over a century. It has been categorized as developmental or acquired depending on whether the onset is in early childhood or beyond, and acquired cases can have degenerative or non-degenerative etiologies. Prosopagnosia has been linked to involvement of the fusiform gyri, mainly in the right hemisphere. The literature on prosopagnosia comprises case reports and small case series. We aim to assess demographic, clinical, and imaging characteristics, and neurological and neuropathological disorders associated with a diagnosis of prosopagnosia in a large cohort. Patients were categorized as developmental versus acquired; those with acquired prosopagnosia were further subdivided into degenerative versus non-degenerative, based on neurological etiology. We assessed regional involvement on 18F-fluorodeoxyglucose PET and MRI of the right and left frontal, temporal, parietal, and occipital lobes. The Intake and Referral Center at the Mayo Clinic identified 487 patients with possible prosopagnosia, of which 336 met study criteria for probable or definite prosopagnosia. Ten patients, 80.0% male, had developmental prosopagnosia including one with Niemann-Pick type C, and another with a Forkhead-box G1 gene mutation. Of the 326 with acquired prosopagnosia, 235 (72.1%) were categorised as degenerative, 91 (27.9%) as non-degenerative. The most common degenerative diagnoses were posterior cortical atrophy, primary prosopagnosia syndrome, Alzheimer’s disease dementia, and semantic dementia, with each diagnosis accounting for >10% of this group. The most common non-degenerative diagnoses were infarcts (ischemic and hemorrhagic), epilepsy-related, and primary brain tumours, each accounting for >10%. We identified a group of patients with non-degenerative transient prosopagnosia in which facial-recognition loss improved or resolved over time. These patients had migraine-related prosopagnosia, posterior reversible encephalopathy syndrome, delirium, hypoxic encephalopathy, and ischemic infarcts. On 18F-fluorodeoxyglucose PET, the temporal lobes proved to be the most frequently affected regions in 117 patients with degenerative prosopagnosia, while in 82 patients with non-degenerative prosopagnosia MRI revealed the right temporal and right occipital lobes as most affected by a focal lesion. The most common pathological findings in those with degenerative prosopagnosia were frontotemporal lobar degeneration with hippocampal sclerosis, and mixed Alzheimer’s and Lewy body disease pathology. In this large case series of patients diagnosed with prosopagnosia, we observed that facial-recognition loss occurs across a wide range of acquired degenerative and non-degenerative neurological disorders, most commonly in males with developmental prosopagnosia. The right temporal and occipital lobes, and connecting fusiform gyrus, are key areas. Multiple different pathologies cause degenerative prosopagnosia.
... It may be relevant to consider evidence from another domain of research that investigates disorders of person recognition: substantial impairments to the recognition of faces (prosopagnosia) or voices (phonagnosia) can be acquired as a result of brain damage (e.g., [82,83]); even in the absence of structural brain changes, such impairments can occur in a "developmental" or "congenital" variant [84,85]. Voice recognition abilities are typically preserved in cases with both developmental [86,87] and acquired prosopagnosia [88], thus suggesting that disorders in face and voice recognition are dissociable. ...
Recognizing people from their voices may be facilitated by a voice’s distinctiveness, in a manner similar to that which has been reported for faces. However, little is known about the neural time-course of voice learning and the role of facial information in voice learning. Based on evidence for audiovisual integration in the recognition of familiar people, we studied the behavioral and electrophysiological correlates of voice learning associated with distinctive or non-distinctive faces. We repeated twelve unfamiliar voices uttering short sentences, together with either distinctive or non-distinctive faces (depicted before and during voice presentation) in six learning-test cycles. During learning, distinctive faces increased early visually-evoked (N170, P200, N250) potentials relative to non-distinctive faces, and face distinctiveness modulated voice-elicited slow EEG activity at the occipito–temporal and fronto-central electrodes. At the test, unimodally-presented voices previously learned with distinctive faces were classified more quickly than were voices learned with non-distinctive faces, and also more quickly than novel voices. Moreover, voices previously learned with faces elicited an N250-like component that was similar in topography to that typically observed for facial stimuli. The preliminary source localization of this voice-induced N250 was compatible with a source in the fusiform gyrus. Taken together, our findings provide support for a theory of early interaction between voice and face processing areas during both learning and voice recognition.
... Two forms of prosopagnosia have been described (but cf. Rossion, 2018): acquired prosopagnosia (AP), which includes patients whose impairments were caused by damage to occipitotemporal regions (Rossion, 2014), and congenital or developmental prosopagnosia, which is characterized by severe lifelong difficulty with face recognition in the absence of acquired brain injury (e.g., Cattaneo et al., 2016;Geskin and Behrmann, 2018;McConachie, 1976;Rosenthal et al., 2017;Thomas et al., 2009). ...
... This literature has generally contributed to the idea that specialised and category-selective neural modules are necessary for functional aspects of face processing (Cohen et al., 2019). Brain imaging findings from individuals born with deficits in face recognition (developmental prosopagnosics; (Avidan et al., 2005;Jiahui et al., 2018;Kaltwasser et al., 2014;McConachie, 1976;Rosenthal et al., 2017) have revealed finer-grained functional neural differences in the processes (Jiahui et al. 2018;Rosenthal et al. 2017;Avidan et al. 2014;Zhao et al. 2018) associated with deficits in face recognition. Overall, the cumulation of these neuropsychological, neuroanatomical and functional components of prosopagnosia (Busigny et al. 2010;Dricot et al. 2008;Rossion 2018;Rossion et al. 2003;Duchaine and Nakayama 2006) has significantly contributed to neural models of face perception in the last two decades (Duchaine & Yovel, 2015;Haxby et al., 2000;White & Mike Burton, 2022). ...
The brains of the best face-recognisers (so-called “super-recognisers”) not only exhibit better mid-level visual computations, but also richer semantic computations (Faghel-Soubeyrand et al., 2022). To further examine the relationship between specific brain computations and recognition ability, we aimed to characterise the computational brain dynamics of an individual at the other end of the spectrum of face recognition abilities, PS, a well-documented case of “pure” acquired prosopagnosia. We collected a large dataset of high-density electrophysiological recordings from PS and neurotypicals (N=19 including 4 aged-matched, ~65K trials) while they completed a one-back task on a succession of face, object, animal and scene images. PS showed archetypal behavioural deficits in this setting, with a larger behavioural impairment for face vs. non-face visual categories. We used Representational Similarity Analysis (RSA) to correlate human EEG representations with those of deep neural networks (DNN) models of vision and semantics, offering a comprehensive characterisation of neural computations in PS and neurotypicals. EEG representational dissimilarity matrices (RDMs) were computed for each participant and time point using cross-validated classifiers. PS’ RDMs showed significant within-subject reliability, indicating meaningful measurements of brain representations with RSA even in the presence of significant lesions. Furthermore, PS’ brain displayed reduced face-identity evidence around 170 ms and 300 ms, as shown by lower RDM similarity with a face-identity model compared to neurotypicals. Crucially, we revealed two representational signatures of PS’ deficits: mid-level visual computations (representations in mid-layers of visual DNNs) and high-level semantic computations (representations of a DNN characterising sentence semantics). Both neuro-functional signatures were found around the N170 and P300 windows. Our results reinforce the view that common brain computations are modulated in individuals with skilled (Faghel-Soubeyrand et al., 2022), typical and now impaired face individuation ability. In other words, mid-level visual and semantic brain computations seem to be involved from prosopagnosia to super-recognition.
... This literature has generally contributed to the idea that specialised and category-selective neural modules are necessary for functional aspects of face processing (Cohen et al., 2019). Brain imaging findings from individuals born with deficits in face recognition (developmental prosopagnosics; (Avidan et al., 2005;Jiahui et al., 2018;Kaltwasser et al., 2014;McConachie, 1976;Rosenthal et al., 2017) have revealed finer-grained functional neural differences in the processes (Jiahui et al. 2018;Rosenthal et al. 2017;Avidan et al. 2014;Zhao et al. 2018) associated with deficits in face recognition. Overall, the cumulation of these neuropsychological, neuroanatomical and functional components of prosopagnosia (Busigny et al. 2010;Dricot et al. 2008;Rossion 2018;Rossion et al. 2003;Duchaine and Nakayama 2006) has significantly contributed to neural models of face perception in the last two decades (Duchaine & Yovel, 2015;Haxby et al., 2000;White & Mike Burton, 2022). ...
We aimed to identify the neural computations underlying the loss of face identification ability by modelling the brain activity of brain-lesioned patient PS, a well-documented case of acquired pure prosopagnosia. We collected a large dataset of high-density electrophysiological (EEG) recordings from PS and neurotypicals while they completed a one-back task on a stream of face, object, animal and scene images. We found reduced neural decoding of face identity around the N170 window in PS, and conjointly revealed normal non-face identification in this patient. We used Representational Similarity Analysis (RSA) to correlate human EEG representations with those of deep neural network (DNN) models of vision and caption-level semantics, offering a window into the neural computations at play in patient PS’s deficits. Brain representational dissimilarity matrices (RDMs) were computed for each participant at 4 ms steps using cross-validated classifiers. PS’s brain RDMs showed significant reliability across sessions, indicating meaningful measurements of brain representations with RSA even in the presence of significant lesions. Crucially, computational analyses were able to reveal PS’s representational deficits in high-level visual and semantic brain computations. Such multi-modal data-driven characterisations of prosopagnosia highlight the complex nature of processes contributing to face recognition in the human brain.
Highlights
We assess the neural computations in the prosopagnosic patient PS using EEG, RSA, and deep neural networks
Neural dynamics of brain-lesioned PS are reliably captured using RSA
Neural decoding shows normal evidence for non-face individuation in PS
Neural decoding shows abnormal neural evidence for face individuation in PS
PS shows impaired high-level visual and semantic neural computations
... Developmental prosopagnosia (DP) is a lifelong disorder characterized by severe difficulties when recognizing facial identity (De Hann, 1999;Duchaine, 2000;Kress & Daum, 2003;McConachie, 1976;Nunn et al., 2001). Its prevalence is commonly reported to be 2-3% (Kennerknecht et al., 2006;Kennerknecht et al., 2008), although one study has suggested this could be as high as 5% . ...
Developmental prosopagnosia is characterised by severe, lifelong difficulties when recognising facial identity. Unfortunately, the most common diagnostic assessment (Cambridge Face Memory Test) misses 50-65% of individuals who believe that they have this condition. This results in such excluded cases’ absence from scientific knowledge, effect sizes of impairment potentially overestimated, treatment efficacy underrated, and may elicit in them a negative experience of research. To estimate their symptomology and group level impairments in face processing, we recruited a large cohort who believes that they have prosopagnosia. Matching prior reports, 56% did not meet criteria on the Cambridge Face Memory Test. However, the severity of their prosopagnosia symptoms and holistic perception deficits were comparable to those who did meet criteria. Excluded cases also exhibited face perception and memory impairments that were roughly one standard deviation below neurotypical norms, indicating the presence of objective problems. As the prosopagnosia index correctly classified virtually every case, we propose it should be the primary method for providing a diagnosis, prior to subtype categorisation. We present researchers with a plan on how they can analyse these excluded prosopagnosia cases in their future work without negatively impacting their traditional findings. We anticipate such inclusion will enhance scientific knowledge, more accurately estimate effect sizes of impairments and treatments, and identify commonalities and distinctions between these different forms of prosopagnosia. Owing to their atypicalities in visual perception, we recommend that the prosopagnosia index should be used to screen out potential prosopagnosia cases from broader vision research.
... In Experiment 2 we used a group-level analysis to examine whether horizontal preference for faces is impaired in developmental prosopagnosia (DP), the lifelong inability to recognize face identity (McConachie, 1976). We did this by comparing the size of the horizontal advantage (i.e., better performance for horizontal trials than for vertical trials) in a DP group against a sex/agematched control group. ...
Face recognition is strongly influenced by the processing of orientation structure in the face image. Faces are much easier to recognize when they are filtered to include only horizontally oriented information compared with vertically oriented information. Here, we investigate whether preferences for horizontal information in faces are related to face recognition abilities in a typical sample (Experiment 1), and whether such preferences are lacking in people with developmental prosopagnosia (DP; Experiment 2). Experiment 1 shows that preferences for horizontal face information are linked to face recognition abilities in a typical sample, with weak evidence of face-selective contributions. Experiment 2 shows that preferences for horizontal face information are comparable in control and DP groups. Our study suggests that preferences for horizontal face information are related to variations in face recognition abilities in the typical range, and that these preferences are not aberrant in DP.
... Face recognition models have suggested that face processing is in fact comprised of discrete independent phases (Bruce & Young, 1986), including processes that permit the representation of a face and its properties, termed face perception, and face memory which pertains to the processes that allow us to store, retain, and retrieve that information. Evidence of these being dissociable can be found in investigations into prosopagnosia, a neurocognitive disorder characterized by impaired face recognition (Bodamer, 1947;McConachie, 1976). While face memory is impaired in both adults and children with prosopagnosia, not all adult cases have displayed impairments in face perception (Busigny et al., 2014;Dalrymple, Fletcher, et al., 2014;Dalrymple, Garrido, & Duchaine, 2014). ...
Grapheme‐color synesthesia is a heterogeneous neurological phenomenon whereby the experience of a grapheme automatically and involuntarily elicits an experience of color. While the majority of synesthesia research has focused on inducer‐specific influences of synesthetic associations, more recent efforts have examined potential broader differences. Based on spontaneous reports from synesthetes detailing problems with face recognition, in conjunction with the geographical proximity of neurological regions relevant to both synesthesia and face processing, we sought to examine whether synesthetes demonstrated atypical face‐processing abilities.
A total of 16 grapheme‐color synesthetes and 16 age‐and‐gender matched controls (±3 years) completed the Cambridge Face Memory Test (CFMT; Duchaine & Nakayama, 2006) of face memory, the Vanderbilt Holistic Face Processing Task (VHPT‐F; Richler, Floyd, & Gauthier, 2014) of holistic face processing, as well as a standardized self‐report questionnaire the Faces and Emotions Questionnaire (Freeman, Palermo, & Brock, 2015). The results revealed significantly poorer performance in synesthete's ability to recognize faces in the CFMT that was driven by a reduction in upright advantage. Results also revealed a significant reduction in overall accuracy on the VHPT‐F for synesthetes, who despite this displayed a comparable holistic processing advantage compared to matched controls. Finally, synesthetes also rated themselves as significantly worse at face recognition. We suggest that this pattern may reflect differences in the development of individualized perceptual strategies.
... Much of the individual differences research literature derives from the observation that there are some individuals who are unusually poor or unusually good at face recognition tasks. In addition to acquired prosopagnosia (the inability to recognize faces as a result of brain damage), there are also people who show poor recognition ability throughout life in the absence of known organic cause, a condition known as developmental prosopagnosia [13][14][15] (or sometimes congenital prosopagnosia: see Box 1). These individuals typically report an inability to recognize familiar people on the basis of their face alone, sometimes termed 'face blindness' . ...
Face perception is crucial to social interactions, yet people vary in how easily they can recognize their friends, verify an identification document or notice someone’s smile. There are widespread differences in people’s ability to recognize faces, and research has particularly focused on exceptionally good or poor recognition performance. In this Review, we synthesize the literature on individual differences in face processing across various tasks including identification and estimates of emotional state and social attributes. The individual differences approach has considerable untapped potential for theoretical progress in understanding the perceptual and cognitive organization of face processing. This approach also has practical consequences — for example, in determining who is best suited to check passports. We also discuss the underlying structural and anatomical predictors of face perception ability. Furthermore, we highlight problems of measurement that pose challenges for the effective study of individual differences. Finally, we note that research in individual differences rarely addresses perception of familiar faces. Despite people’s everyday experience of being ‘good’ or ‘bad’ with faces, a theory of how people recognize their friends remains elusive. The ability to recognize identity, emotion and other attributes from faces varies across individuals. In this Review, White and Burton synthesize research on individual differences in face processing and the implications of variability in face processing ability for theory and applied settings.
... Face recognition is a key skill for social interaction. In developmental prosopagnosia (DP), face recognition is impaired without a history of brain damage and affects about 2% of the population (Kennerknecht et al., 2006Bowles et al., 2009), with strong indications for heritability for the ability to recognize faces (McConachie, 1976;Duchaine et al., 2007;Kennerknecht et al., 2008Kennerknecht et al., , 2011. ...
Rationale:
Face expertise is a pivotal social skill. Developmental prosopagnosia (DP), i.e., the inability to recognize faces without a history of brain damage, affects about 2% of the general population, and is a renowned model system of the face-processing network. Within this network, the right Fusiform Face Area (FFA), is particularly involved in face identity processing and may therefore be a key element in DP. Neural representations within the FFA have been examined with Representational Similarity Analysis (RSA), a data-analytical framework in which multi-unit measures of brain activity are assessed with correlation analysis.
Objectives:
Our study intended to scrutinize modifications of FFA-activation during face encoding and maintenance based on RSA.
Methods:
Thirteen participants with DP (23–70 years) and 12 healthy control subjects (19–62 years) participated in a functional MRI study, including morphological MRI, a functional FFA-localizer and a modified Sternberg paradigm probing face memory encoding and maintenance. Memory maintenance of one, two, or four faces represented low, medium, and high memory load. We examined conventional activation differences in response to working memory load and applied RSA to compute individual correlation-matrices on the voxel level. Group correlation-matrices were compared via Donsker’s random walk analysis.
Results:
On the functional level, increased memory load entailed both a higher absolute FFA-activation level and a higher degree of correlation between activated voxels. Both aspects were deficient in DP. Interestingly, control participants showed a homogeneous degree of correlation for successful trials during the experiment. In DP-participants, correlation levels between FFA-voxels were significantly lower and were less sustained during the experiment. In behavioral terms, DP-participants performed poorer and had longer reaction times in relation to DP-severity. Furthermore, correlation levels were negatively correlated with reaction times for the most demanding high load condition.
Conclusion: We suggest that participants with DP fail to generate robust and maintained neural representations in the FFA during face encoding and maintenance, in line with poorer task performance and prolonged reaction times. In DP, alterations of neural coding in the FFA might therefore explain curtailing in working memory and contribute to impaired long-term memory and mental imagery.
... The strongest case for the dissociation of identity and emotion recognition is based on the existence of specific deficits that impair one ability and not the other (Etcoff 1984;Young et al. 1993;Bentin et al. 2007). Prosopagnosia is a deficit in face identity recognition that can follow a cerebral lesion (Bodamer 1947) or be present from birth in the absence of brain injury (McConachie 1976), and in which emotion recognition seems to Handling editor: Bruno Laeng (University of Oslo); Reviewers: Tetsuto Minami (Toyohashi University of Technology) and a second researcher who prefers to remain anonymous. be usually preserved (Duchaine et al. 2003). ...
Recognition of identity and of emotional facial expressions of individuals are both based on processing of the human face. While most studies show these abilities to be dissociated, some others find evidence of a connection. One possible explanation for these contradictory results comes from neurological evidence, which points to identity recognition being mostly based on holistic processing, while emotion recognition seems to be based on both an explicit, fine-grained process, and an implicit, mostly-holistic one. Our main hypothesis, that would explain the contradictory findings, is that holistic implicit emotion recognition, specifically, would be related to identity recognition, while explicit emotion recognition would be a process separate to identity recognition. To test this hypothesis, we employed an experimental paradigm in which spatial frequencies of visual stimuli are manipulated so that automatic, holistic-based, implicit emotion recognition influences perceived friendliness of unfamiliar faces. We predicted the effect to be related to identity recognition ability, since they both require holistic face processing. After a successful replication study, we employed the paradigm with 140 participants, measuring also identity recognition ability and explicit emotion recognition ability. Results showed that the effect is not moderated by these two variables (p = .807 and .373, respectively), suggesting that the independence of identity and emotion recognition holds even when considering, specifically, implicit emotion recognition.
... The difficulties in face perception also extend to perceiving one's own face, as Sacks writes: "On several occasions I have apologised for almost bumping into a large bearded man, only to realize that the large bearded man was myself in a mirror." This condition can either be acquired after stroke or brain injury, or can be congenital (McConachie, 1976), and usually occurs following damage to a specific region of cortex: the fusiform gyrus. Such a condition sparked interest in face processing, as the case of prosopagnosia seemed to suggest that the brain had a specific face processing 'module' that could be selectively damaged. ...
This thesis provides novel neuroimaging insights into the brain activity related to the processing of highly salient infant faces. Specifically, I provide new information about the spatial and temporal aspects of brain activity for processing infant faces within four experimental investigations. Overall, the presented findings provide novel, important insights into: (1) our current understanding of how the brain processes salient, infant faces, (2) human face perception more generally, and (3) potential implications for how we provide care to our young.
In Chapter 1, I review the literature on human face processing, and infant face processing. I draw together insights from prosopagnosia and single-cell studies in primates, moving on to discuss functional neuroimaging findings highlighting a dedicated spatial network of regions for face processing within the brain. The current evidence has good knowledge of ‘what’ and ‘where,’ but lacks a temporal dimension: ‘when.’ I then move on to discuss models of face perception, and how the dominant narrative involves a hierarchical, feedforward process, which is at odds with current knowledge about top-down interactions between brain regions. Lastly, I summarise our current understanding of human parental brain networks.
In Chapter 2, I present two quantitative meta-analyses of aggregated fMRI data, using activation likelihood estimation (ALE) analysis. First, I explore nulliparous women viewing infant faces, and second, I explore mothers viewing their own infants’ face. I present findings relating to the spatial coordinates of these two intriguing contrasts, including the apparent left lateralisation of infant face processing in motherhood. I reflect upon how the field of fMRI studies has thus far been limited in its ability to explain the temporal dimension of face processing (“when”) and set a precedent for a greater exploration of infant face processing using temporally sensitive brain imaging methodology and analytic methods.
In Chapter 3, I present the analysis of a dataset exploring how the human brain processes infant and adult faces, replicating previous findings of a privileged processing route when viewing infant faces to support sensitive and swift caregiving. I then advance the field by exploring how the human brain also processes juvenile and adult animal faces to test the hypothesis that the infant schema may operate in a cross-species fashion. I report evidence demonstrating that baby animals (kittens and puppies) also trigger an early orbitofrontal cortex response (120ms), that guides the brain to provide sensitive caregiving – “cuteness ignition”.
In Chapter 4, I analyse the same dataset as in Chapter 3, this time using a classifier (discriminant analysis) to pose the question as to how the adult brain categorises different kinds of faces. This chapter provides proof of principle for the ability of classification analysis to discover the spatiotemporal features needed to separate and predict up to six classes of face stimuli. The importance of the beta band and the time window of 60-180ms post stimulus presentation for face categorisation are both emphasised. The results provide further evidence for the importance of “when” components in brain activity within the human brain, especially when it comes to distinguishing between highly salient categories such as “cute” baby and baby animal faces. This method also provides exciting new avenues for research into the human parental brain and temporally sensitive parent-infant interactions.
Chapter 5 addresses how we can use more nuanced experimental paradigms in fMRI, combined with sensitive network analysis, to draw inferences about how the brain learns about characterological features of infant faces (emotionality). While previous chapters explored the short ‘when’ of infant face processing, this chapter addresses the long ‘when’ involving learning. I report upon a network involving orbitofrontal cortex, amygdala and hippocampus, which is more active for infant faces with a happier temperament and expression of emotionality. This has important implications for social learning, and perhaps for attachment and empathy.
Lastly, in Chapter 6 I conclude by drawing together all findings from the thesis to demonstrate how a comprehensive understanding of cognitive processes within the brain necessitates ‘what,’ ‘where,’ and crucially, ‘when’ information. I discuss how this thesis provides evidence of parallel processing pathways, and the likely presence of top-down predictions arising from this structure. I discuss the crucial role of the orbitofrontal cortex in salient face processing, and advance a new theoretical model for salient face processing that unites ‘cuteness ignition’ with current theoretical top-down models of object processing.
... Here, rare cases of facial identity recognition deficits in the context of acquired prosopagnosia (difficulties that present following neurological illness or injury, typically affecting occipitotemporal areas, e.g., Barton, 2008;De Renzi et al., 1994) have long been used to inform our understanding of the structure and functioning of the typical face recognition system (e.g., Bruce & Young, 1986). In recent decades, a developmental form of the same condition has been reported (e.g., De Haan & Campbell, 1991;Duchaine, 2000;McConachie, 1976) that is more common than its acquired counterpart (Bennetts, Murray, et al., 2017;Bowles et al., 2009), occurring in the absence of neurological injury or other visual, cognitive or emotional dysfunction (Duchaine et al., 2007). However, given anecdotal and objective variation in the severity of face recognition difficulties in developmental prosopagnosia (Adams et al., 2020;Bate, Bennetts, Gregory, et al., 2019;Murray et al., 2018), coupled with apparently broad individual differences in face recognition abilities within the typical population (Wilmer, 2017), it remains unknown whether developmental difficulties truly represent a distinct pathology akin to the acquired form of prosopagnosia (Barton & Corrow, 2016;Bate & Tree, 2017). ...
In the last decade, a novel individual differences approach has emerged across the face recognition literature. While the field has long been concerned with prosopagnosia (the inability to recognise facial identity), it has more recently become clear that there are vast differences in face recognition ability within the typical population. “Super-recognisers” are those individuals purported to reside at the very top of this spectrum. On the one hand, these people are of interest to cognitive neuropsychologists who are motivated to explore the commonality of the face recognition continuum, whereas researchers from the forensic face matching field evaluate the implementation of super-recognisers into real-world police and security settings. These two rather different approaches have led to discrepancies in the definition of super-recognisers, and perhaps more fundamentally, the approach to identifying them, resulting in a lack of consistency that prohibits theoretical progress. Here, we review the protocols used in published work to identify super-recognisers, and propose a common definition and screening recommendations that can be adhered to across fields.
... Currently it is unclear why some individuals do not benefit from face-voice learning. Although findings from developmental prosopagnosia (McConachie, 1976), that is, a severe deficit in face-identity processing, suggest that it may be related to face processing abilities (Maguinness & von Kriegstein, 2017;von Kriegstein et al., 2008). Other evidence of interactions (Bülthoff & Newell, 2015 and relationships between face-and voiceidentity recognition abilities in the neurotypical population (Jenkins et al., 2020), suggest that a common coding system may underpin this enhancement i.e., similar computations in different modalities. ...
Recognising the identity of voices is a key ingredient of communication. Visual mechanisms support this ability: recognition is better for voices previously learned with their corresponding face (compared to a control condition). This so-called ‘face-benefit’ is supported by the fusiform face area (FFA), a region sensitive to facial form and identity. Behavioural findings indicate that the face-benefit increases in noisy listening conditions. The neural mechanisms for this increase are unknown. Here, using functional magnetic resonance imaging, we examined responses in face-sensitive regions while participants recognised the identity of auditory-only speakers (previously learned by face) in high (SNR −4 dB) and low (SNR +4 dB) levels of auditory noise. We observed a face-benefit in both noise levels, for most participants (16 of 21). In high-noise, the recognition of face-learned speakers engaged the right posterior superior temporal sulcus motion-sensitive face area (pSTS-mFA), a region implicated in the processing of dynamic facial cues. The face-benefit in high-noise also correlated positively with increased functional connectivity between this region and voice-sensitive regions in the temporal lobe in the group of 16 participants with a behavioural face-benefit. In low-noise, the face-benefit was robustly associated with increased responses in the FFA and to a lesser extent the right pSTS-mFA. The findings highlight the remarkably adaptive nature of the visual network supporting voice-identity recognition in auditory-only listening conditions.
... Face identification research using recognition-memory (e.g., McCaffery et al., 2018;Robertson et al., 2016;Russell et al., 2009) and simultaneous matching paradigms (e.g., Bate et al., 2019;Bate & Bennetts, 2014;Burton et al., 2010;McCaffery et al., 2018) has revealed large individual differences in ability in the neuro-typical population. These lie on a continuum ranging from developmental prosopagnosics (e.g., Knutson et al., 2011;McConachie, 1976), who display dysfunctional familiar face recognition; to super-recognisers, who display outstanding unfamiliar face recognition (e.g., Bate et al., 2018;Bobak, Bennetts, et al., 2016;Bobak, Hancock, & Bate, 2016). These individual differences are heritable and face-specific, in that only weak correlations are found with non-face object recognition and other visual processing skills (e.g., Dunn et al., 2020;McCaffery et al., 2018;Royer et al., 2018;Verhallen et al., 2017;Wilhelm, Herzmann, et al., 2010;Wilmer, Germine, et al., 2010;Yovel et al., 2014). ...
Individual differences in face identification ability range from prosopagnosia to super‐recognition. The current study examined whether face identification ability predicts voice identification ability (participants: N = 529). Superior‐face‐identifiers (exceptional at face memory and matching), superior‐face‐recognisers (exceptional at face memory only), superior‐face‐matchers (exceptional face matchers only), and controls completed the Bangor Voice Matching Test, Glasgow Voice Memory Test, and a Famous Voice Recognition Test. Meeting predictions, those possessing exceptional face memory and matching skills outperformed typical‐range face groups at voice memory and voice matching respectively. Proportionally more super‐face‐identifiers also achieved our super‐voice‐recogniser criteria on two or more tests. Underlying cross‐modality (voices vs. faces) and cross‐task (memory vs. perception) mechanisms may therefore drive superior performances. Dissociations between Glasgow Voice Memory Test voice and bell recognition also suggest voice‐specific effects to match those found with faces. These findings have applied implications for policing, particularly in cases when only suspect voice clips are available.
... Currently it is unclear why some individuals do not benefit from face-voice learning. Although findings from developmental prosopagnosia (McConachie, 1976), i.e., a severe deficit in face-identity processing, suggest that it may be related to face processing abilities (von Kriegstein, Kleinschmidt and Giraud, 2006;von Kriegstein et al., 2008;Maguinness and von Kriegstein, 2017). Other evidence of interactions Newell, 2015, 2017) and relationships between face-and voiceidentity recognition abilities in the neurotypical population (Jenkins et al., 2020), suggest that a common coding system may underpin this enhancement i.e., similar computations in different modalities. ...
Recognising the identity of voices is a key ingredient of communication. Visual mechanisms support this ability: recognition is better for voices previously learned with their corresponding face (compared to a control condition). This so-called ‘face-benefit’ is supported by the fusiform face area (FFA), a region sensitive to facial form and identity. Behavioural findings indicate that the face-benefit increases in noisy listening conditions. The neural mechanisms for this increase are unknown. Here, using functional magnetic resonance imaging, we examined responses in face-sensitive regions while participants recognised the identity of auditory-only speakers (previously learned by face) in high (SNR -4 dB) and low (SNR 4 dB) levels of auditory noise. We observed a face-benefit in both noise levels, for most participants (16 of 21). In high-noise, the recognition of face-learned speakers engaged the right posterior superior temporal sulcus motion-sensitive face area (pSTS-mFA), a region implicated in the processing of dynamic facial cues. The face-benefit in high-noise also correlated positively with increased functional connectivity between this region and voice-sensitive regions in the temporal lobe in the group of 16 participants with a behavioural face-benefit. In low-noise, the face-benefit was robustly associated with increased responses in the FFA and to a lesser extent the right pSTS-mFA. The findings highlight the remarkably adaptive nature of the visual network supporting voice-identity recognition in auditory-only listening conditions.
... Rather, findings from autism spectrum disorder suggest that the face-benefit for auditory-only speech processing may relate to differences in lip-reading abilities (von Kriegstein, Kleinschmidt and Giraud, 2006;von Kriegstein et al., 2008;Maguinness and von Kriegstein, 2017). While findings from developmental prosopagnosia (McConachie, 1976), i.e., a severe deficit in face-identity processing, implicate intact face-identity processing as a necessary component for the face-benefit on voice-identity processing (von Kriegstein, Kleinschmidt and Giraud, 2006;von Kriegstein et al., 2008;Maguinness and von Kriegstein, 2017). ...
Perception of human communication signals is often more robust when there is concurrent input from the auditory and visual sensory modality. For instance, seeing the dynamic articulatory movements of a speaker, in addition to hearing their voice, can help with understanding what is said. This is particularly evident in noisy listening conditions. Even in the absence of concurrent visual input, visual mechanisms continue to be recruited to optimise auditory processing: auditory-only speech and voice-identity recognition is superior for speakers who have been previously learned with their corresponding face, in comparison to an audio-visual control condition; an effect termed the “face-benefit”. Whether the face-benefit can assist in maintaining robust perception in noisy listening conditions, in a similar manner to concurrent visual input, is currently unknown. Here, in two behavioural experiments, we explicitly examined this hypothesis. In each experiment, participants learned a series of speakers’ voices together with their corresponding dynamic face, or a visual control image depicting the speaker’s occupation. Following learning, participants listened to auditory-only sentences spoken by the same speakers and were asked to recognise the content of the sentences (i.e., speech recognition, Experiment 1) or the identity of the speaker (i.e., voice-identity recognition, Experiment 2) in different levels of increasing auditory noise (SNR +4 dB to -8 dB). For both speech and voice-identity recognition, we observed that for participants who showed a face-benefit, the benefit increased with the degree of noise in the auditory signal (Experiment 1, 2). Taken together, these results support an audio-visual model of human auditory communication and suggest that the brain has developed a flexible system to deal with auditory uncertainty – learned visual mechanisms are recruited to enhance the recognition of the auditory signal.
... These have ranged from those with developmental or acquired face recognition deficits, prosopagnosia (eg, Knutson, DeTucci, & Grafman, 2011;McConachie, 1976), to those that possess naturally exceptional levels of face identification ability, super-face-recognisers (eg, Davis, Lander, Evans, & Jansari, 2016;Bobak, Bennetts, Parris, Jansari, & Bate, 2016;Russell, Duchaine, & Nakayama, 2009). Similarly, analogous recognition deficits have also emerged for voices, phonagnosia (eg, Assal, Zander, Kremin, & Buttet, 1976;Van Lancker & Canter, 1982), however no research has examined superior voice processing. ...
... Developmental prosopagnosia (DP) is a life-long severe deficit in the ability to recognise the identity of faces that cannot be accounted for by low-level visual or intellectual impairments, and without any known neurological history (McConachie, 1976;Behrmann & Avidan, 2005). Individuals with DP have difficulties remembering the faces of familiar individuals and many also have problems discriminating between pictures of different unfamiliar faces (e.g., Duchaine et al., 2007). ...
We investigated selective impairments of visual identity discrimination in developmental prosopagnosia (DP), using a fast periodic identity oddball stimulation paradigm with electroencephalography (EEG). In Experiment 1, neural responses to unfamiliar face identity changes were strongly attenuated for individuals with DP as compared to Control participants, to the same extent for upright and inverted faces. This reduction of face identity discrimination responses, which was confirmed in Experiment 2, provides direct evidence for deficits in the visual processing of unfamiliar facial identity in DP. Importantly, Experiment 2 demonstrated that DPs showed attenuated neural responses to identity oddballs not only with face images, but also with non-face images (cars). This result strongly suggests that rapid identity-related visual processing impairments in DP are not restricted to faces, but also affect familiar classes of non-face stimuli. Visual discrimination deficits in DP do not appear to be face-specific. To account for these findings, we propose a new account of DP as a domain-general deficit in rapid visual discrimination.
... Developmental Prosopagnosia is a rare disorder characterized by defective recognition of familiar faces, in the absence of an established neurological disease or brain lesion. Only five cases have been described in the literature, AB (De Haan and Campbell, 1991;McConachie, 1976), Dr S (Temple, 1992), YT (Bentin et al, 1999), BC (Duchaine, 2000) and EP (Nunn et al, 2001), and their pattern of deficits and abilities in processing unfamiliar and familiar faces mirrors the spectrum seen in the acquired disorder, confirming that prosopagnosia is not a unitary symptom. According to the Bruce and Young (1986) and names. ...
In this thesis, Position Emission Tomography (PET) was used to investigate how the human brain identifies the faces and proper names of famous people. The first experiment illustrated that identifying known individuals from either their faces or their proper names, activated a widespread neural system in the left hemisphere extending from the anterior temporal to the posterior temporo-parietal regions. To investigate the specificity of these responses for famous people, two further PET studies were performed in which famous faces were compared to other categories of objects (animals, man-made objects, body parts, maps and colours) presented as pictures and famous proper names were compared to names of common objects. Both studies revealed that a specific region in the left anterior temporal lobe was more active for famous faces and proper names than for objects, suggesting a segregation of the neural substrates necessary for retrieving semantic attributes about known people. Alternatively, the preferential response of the anterior temporal cortex for famous people could be explained by greater demands on semantic retrieval processes when the semantic attributes of a stimulus are unique but the visual features are shared by many other members of the same category. To test this hypothesis, the brain response to famous buildings and landmarks was investigated since they are linked, like famous faces, to unique semantic information. Indeed, the anterior temporal lobe was activated by famous buildings as well as famous faces. These studies on normal subjects therefore suggested that the anterior temporal lobe is implicated in retrieval of specific semantic information about unique items. However, in normal language processing, identification and naming occur together highly automatically and it is difficult to disentangle them. A patient with a severe deficit in naming (anomia) famous faces was therefore studied. The patient was able to access semantic but not lexical information and showed a normal anterior temporal cortex response. Taken together, the results of both normal and patient studies suggest that the left anterior temporal cortex is involved in: i) Retrieving specific semantic information about known people regardless of the modality of presentation of the stimuli, i.e. both from faces and proper names; ii) Identification of other categories of unique items, such as famous buildings and landmarks; and iii) Identification more than naming.
... Many DPs experience subtle problems recognising facial expressions (Biotti & Cook, 2016) and facial sex (Esins, Schultz, Stemper, Kennerknecht, & Bulthoff, 2016;Marsh, Biotti, Cook, & Gray, 2019), and some show signs of co-occurring body (Biotti, Gray, & Cook, 2017) and object recognition difficulties (Geskin & Behrmann, 2017;. Cases of DP were once thought to be rare (McConachie, 1976), however current estimates suggest that ~2% of the general population may experience lifelong face recognition difficulties severe enough to disrupt their daily lives (Kennerknecht et al., 2006;Kennerknecht, Ho, & Wong, 2008). ...
The nature of the perceptual deficit seen in developmental prosopagnosia remains poorly understood. One possibility is that these individuals experience face recognition difficulties because they fail to process faces holistically; they may be less able to analyze distal regions in parallel and therefore struggle to integrate information from different regions into a unified perceptual whole. Consequently, developmental prosopagnosics may be forced to base perceptual decisions on a slow, effortful piecemeal analysis of local facial features. In the present study, we sought to test this view by comparing the face recognition of developmental prosopagnosics and typical observers under two viewing conditions: when target faces were briefly presented in their entirety, and when they were inspected region-by-region through a dynamic aperture. If developmental prosopagnosics are forced to base perceptual decisions on information accumulated from a serial piecemeal analysis, one would expect little if any decrement in performance when target faces are viewed through apertures. Contrary to this prediction, however, developmental prosopagnosics showed strong aperture effects comparable with typical observers; their perceptual decisions were more accurate in the whole-face condition than when targets were viewed through the aperture. As expected, the developmental prosopagnosics were less accurate than typical controls when judging briefly presented faces shown in their entirety. Strikingly, however, they were also less able to accumulate perceptual evidence from a serial region-by-region analysis, than typical observers. Our results suggest that the perceptual problems seen in this population arise from imprecise descriptions of local regions, not aberrant holistic processing.
... 8 Another long-term outcome of this early literature has been the recognition of the syndrome of developmental prosopagnosia, 8 in which subjects fail to develop facial recognition skills, but have normal high-level visual skills and memory. Although described in the 1970s, 9 it was felt for many years to be exceedingly rare and gained little attention. The developmental form of 'face blindness' appears, however, to be far commoner than the acquired version and was highlighted in a very recent BBC Radio 4 interview with Stephen Fry (https://www. ...
The Diagnostic Statistical Manual of Mental Disorders (DSM-5) recommends diagnosing neurocognitive disorders (i.e., cognitive impairment) when a patient scores beyond -1 SD below neurotypical norms on two tests. I review how this approach will fail due to cognitive tests’ power limitations, validity issues, imperfect reliabilities, and biases, before summarising their resulting negative consequences. As a proof of concept, I use developmental prosopagnosia, a condition characterised by difficulties recognising faces, to show the DSM-5 only diagnoses 62-70% (n1 = 61, n2 = 165) versus 100% (n1 = 61) through symptoms alone. Pooling the DSM-5 missed cases confirmed the presence of group-level impairments on objective tests, which were further evidenced through meta-analyses, thus validating their highly atypical symptoms. These findings support a paradigm shift towards bespoke diagnostic approaches for distinct cognitive impairments, including a symptom-based method when validated effective. I reject dogmatic adherence to the DSM-5 approach to neurocognitive disorders, and underscore the importance of a data driven, transdiagnostic approach to understanding patients’ subjective cognitive impairments. This will ultimately benefit patients, their families, clinicians, and scientific progress.
There has been a long-standing debate in philosophy and psychology about the role of representation in visual perception. Here, we argue based on evidence from philosophy, psychology, and neuroscience that episodic and schematic memory representations are pivotal to the visual perception of objects and scenes. In the visual perception of objects and scenes, sensory information is initially matched with object and scene templates, or schemas, in long-term memory. The most relevant representations are then selected for encoding in working memory. We furthermore argue that activations of episodic memory representations contribute to the fineness of grain of visual representations. The representational view of visual perception that emerges is what we call the “template tuning view.” According to this view, prior information –specifically, long-term memories – shape the representational content of visual perception. In the final section of the chapter, we argue that unlike representational conceptions of visual perception, naïve and direct realist theories have difficulties accommodating these findings.
We report an investigation of the neural processes involved in the processing of faces and objects of brain-lesioned patient PS, a well-documented case of pure acquired prosopagnosia. We gathered a substantial dataset of high-density electrophysiological recordings from both PS and neurotypicals. Using representational similarity analysis, we produced time-resolved brain representations in a format that facilitates direct comparisons across time points, different individuals, and computational models. To understand how the lesions in PS’s ventral stream affect the temporal evolution of her brain representations, we computed the temporal generalization of her brain representations. We uncovered that PS’s early brain representations exhibit an unusual similarity to later representations, implying an excessive generalization of early visual patterns. To reveal the underlying computational deficits, we correlated PS’ brain representations with those of deep neural networks (DNN). We found that the computations underlying PS’ brain activity bore a closer resemblance to early layers of a visual DNN than those of controls. However, the brain representations in neurotypicals became more akin to those of the later layers of the model compared to PS. We confirmed PS’s deficits in high-level brain representations by demonstrating that her brain representations exhibited less similarity with those of a DNN of semantics.
The PI20 is a self-report questionnaire that assesses the presence of lifelong face recognition difficulties. The items on this scale ask respondents to assess their face recognition ability relative to the rest of the population, either explicitly or implicitly. Recent reports suggest that the PI20 scores of autistic participants exhibit little or no correlation with their performance on the Cambridge Face Memory Test – a key measure of face recognition ability. These reports are suggestive of a meta-cognitive deficit whereby autistic individuals are unable to infer whether their face recognition is impaired relative to the wider population. In the present study, however, we observed significant correlations between the PI20 scores of 77 autistic adults and their performance on two variants of the Cambridge Face Memory Test. These findings indicate that autistic individuals can infer whether their face recognition ability is impaired. Consistent with previous research, we observed a wide spread of face recognition abilities within our autistic sample. While some individuals approached ceiling levels of performance, others met the prevailing diagnostic criteria for developmental prosopagnosia. This variability showed little or no association with non-verbal intelligence, autism severity, or the presence of co-occurring alexithymia or ADHD.
Individuals with developmental prosopagnosia (DPs) experience severe and lifelong deficits recognising faces, but whether their deficits are selective to the processing of face identity or extend to the processing of face expression remains unclear. Clarifying this issue is important for understanding DP impairments and advancing theories of face processing. We compared identity and expression processing in a large sample of DPs (N = 124) using three different matching tasks that each assessed identity and expression processing with identical experimental formats. We ran each task in upright and inverted orientations and we measured inversion effects to assess the integrity of upright-specific face processes. We report three main results. First, DPs showed large deficits at discriminating identity but only subtle deficits at discriminating expression. Second, DPs showed a reduced inversion effect for identity but a normal inversion effect for expression. Third, DPs' performance on the expression tasks were linked to autism traits, but their performance on the identity tasks were not. These results constitute several dissociations between identity and expression processing in DP, and they are consistent with the view that the core impairment in DP is highly selective to identity.
The prevalence of developmental prosopagnosia (DP), lifelong face recognition deficits, is widely reported to be 2-2.5%. However, DP has been diagnosed in different ways across studies, resulting in differing prevalence rates. In the current investigation, we estimated the range of DP prevalence by administering well-validated objective and subjective face recognition measures to an unselected web-based sample of 3116 18-55 year-olds and applying DP diagnostic cutoffs from the last 14 years. We found estimated prevalence rates ranged from .64-5.42% when using a z-score approach and .13-2.95% when using a percentile approach, with the most commonly used cutoffs by researchers having a prevalence rate of .93% (z-score, .45% when using percentiles). We next used multiple cluster analyses to examine whether there was a natural grouping of poorer face recognizers but failed to find consistent grouping beyond those with generally above versus below average face recognition. Lastly, we investigated whether DP studies with more relaxed diagnostic cutoffs were associated with better performance on the Cambridge Face Perception Test. In a sample of 43 studies, there was a weak nonsignificant association between greater diagnostic strictness and better DP face perception accuracy (Kendall's tau-b correlation, τb =.18 z-score; τb = .11 percentiles). Together, these results suggest that researchers have used more conservative DP diagnostic cutoffs than the widely reported 2-2.5% prevalence. We discuss the strengths and weaknesses of using more inclusive cutoffs, such as identifying mild and major forms of DP based on DSM-5.
Following traumatic brain injury in adulthood, Pierrette Sapey (PS) became suddenly unable to recognize the identity of people from their faces. Thanks to her remarkable recovery of general brain function, liveliness, and willingness to be tested, PS's case of prosopagnosia has been extensively studied for more than 20 years. This investigation includes hundreds of hours of behavioral data collection that provide information about the nature of human face identity recognition (FIR). Here a theory-driven extensive review of behavioral and eye movement recording studies performed with PS is presented (part I). The specificity of PS's recognition disorder to the category of faces, i.e., with preserved visual object (identity) recognition, is emphasized, arguing that isolating this impairment is necessary to define prosopagnosia, offering a unique window to understand the nature of human FIR. Studies performed with both unfamiliar and experimentally or naturally familiar faces show that PS, while being able to perceive both detailed diagnostic facial parts and a coarse global facial shape, can no longer build a relatively fine-grained holistic visual representation of a face, preventing its efficient individuation. Her mandatory part-by-part analytic behavior during FIR causes increased difficulties at extracting diagnostic cues from the crowded eye region of the face, but also from relative distances between facial parts and from 3D shape more than from surface cues. PS's impairment is interpreted here for the first time in terms of defective (access to) cortical memories of faces following brain damage, causing her impaired holistic perception of face individuality. Implications for revising standard neurofunctional models of human face recognition and evaluation of this function in neurotypical individuals are derived.
Next-generation sequencing techniques have accelerated the discovery of rare mutations responsible for autism spectrum disorder (ASD) in genes involved in a large number of physiological processes, including the control of gene expression, chromatin remodeling, signaling pathways, synaptic scaffolding, neurotransmitter receptors, and lipid metabolism. Genetic diagnosis provides subjects with an explanation of the cause of their disorder. However, it does not, or at least does not yet, shed light on the psychopathological phenomena specific to the individual. It could be hypothesized that each physiological impact of a mutation corresponds to a specific psychopathological phenomenon of ASD, i.e., “a psychopathological natural kind”. We discuss here the difficulties identifying this specificity of underlying psychopathology in individuals with ASD due to a rare mutation with a major effect. A comparison of Newson's pathological demand avoidance and Wing's Asperger's syndrome with Asperger's autistic psychopathy highlights different ways of approaching psychopathological descriptions and diagnosis, by focusing on either common or unusual features. Such a comparison calls into question the principles of clinical research recommended by Falret for characterizing “disease individuality” of ASD due to a rare mutation.
Two key functions in human face perception are gaze discrimination and identity recognition. Here we examine whether gaze discrimination can be intact when identity recognition is impaired in developmental prosopagnosia (DP). We ran a large sample of developmental prosopagnosics (DPs) with a series of gaze discrimination tasks that assess various mechanisms in gaze processing. Experiment 1 (N = 101 DP participants) investigates spatial processing using an abnormal eye gaze detection task and a Wollaston illusion task that measures perceptual integration of eye and head direction. Experiment 2 (N = 45 DP participants) investigates temporal processing using an adaptation task and a serial dependence task. Despite their deficits with identity recognition, DPs performed in the normal range across both experiments. These results demonstrate that gaze discrimination can be normal in DP, and that various mechanisms of gaze processing can be spared when identity recognition is impaired. Our findings clarify the highly selective nature of impairments in DP and provide support for neurocognitive models of face perception with distinct mechanisms for gaze and identity processing.
In recent years, the number of face identity matching tests in circulation has grown considerably and these are being increasingly utilized to study individual differences in face cognition. Although many of these tests were designed for testing typical observers, recent studies have begun to utilize general-purpose tests for studying specific, atypical populations (e.g., super-recognizers and individuals with prosopagnosia). In this study, we examined the capacity of four tests requiring binary face-matching decisions to study individual differences between healthy observers. Uniquely, we used performance of the patient PS (Rossion, 2018), a well-documented case of acquired prosopagnosia (AP), as a benchmark. Two main findings emerged: (i) PS could exhibit typical rates of accuracy in all tests; (ii) compared to age-matched controls and when considering both accuracy and speed to account for potential trade-offs, only the KFMT — but not the EFCT, PICT or GFMT — was able to detect PS’s severe impairment. These findings reflect the importance of considering both accuracy and response times to measure individual differences in face matching, and the need for comparing tests in terms of their sensitivity, when used as a measure of human cognition and brain functioning.
The Twenty Item Prosopagnosia Index (PI20) is a self-report questionnaire used for quantifying prosopagnosic traits. This scale is intended to help researchers identify cases of developmental prosopagnosia by providing standardized self-report evidence to complement diagnostic evidence obtained from objective computer-based tasks. In order to respond appropriately to items, prosopagnosics must have some insight that their face recognition is well below average, while non-prosopagnosics need to understand that their relative face recognition ability falls within the typical range. There has been considerable debate about whether participants have the necessary insight into their face recognition abilities to respond appropriately. In the present study, we sought to determine whether the PI20 provides meaningful evidence of face recognition impairment. In keeping with the intended use of the instrument, we used PI20 scores to identify two groups: high-PI20 scorers (those with self-reported face recognition difficulties) and low-PI20 scorers (those with no self-reported face recognition difficulties). We found that participant groups distinguished on the basis of PI20 scores clearly differed in terms of their mean performance on objective measures of face recognition ability. We also found that high-PI20 scorers were more likely to achieve levels of face recognition accuracy associated with developmental prosopagnosia.
Developmental prosopagnosia (DP) is a selective neurodevelopmental condition defined by lifelong impairments in face recognition. Despite much research, the extent to which DP is associated with broader visual deficits beyond face processing is unclear. Here we investigate whether DP is accompanied by deficits in colour perception. We tested a large sample of 92 DP individuals and 92 sex/age-matched controls using the well-validated Ishihara and Farnsworth–Munsell 100-Hue tests to assess red–green colour deficiencies and hue discrimination abilities. Group-level analyses show comparable performance between DP and control individuals across both tests, and single-case analyses indicate that the prevalence of colour deficits is low and comparable to that in the general population. Our study clarifies that DP is not linked to colour perception deficits and constrains theories of DP that seek to account for a larger range of visual deficits beyond face recognition.
Prosopagnosia, also known as facial blindness, has attracted wide attention in the social field in recent years. However, it mainly depends on the self-report of the chief complaint in the actual diagnosis. In addition, there is a lack of standardized measurement basis, which brings a lot of inconvenience to the patients themselves and follow-up researchers. In this study, we tested the reliability and validity of the Chinese version of 20 - item prosopagnosia index (PI-20). 647 young people aged 18-45 filled in PI-20, the adult autistic quotient scale, the empathy quotient questionnaire, and completed the retest one month later. Results showed that the PI-20 has good internal consistency reliability, test-retest reliability, and has good validity. In addition, confirmatory factor analysis shows that the model can well fit the data of Chinese population and can be used for large-scale measurement. The Chinese version PI-20 is a reliable measurement for prosopagnosia.
Examination tools such as functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) have enabled extensive research in neuroanatomy in normal subjects and in individuals with congenital or acquired prosopagnosia. Greater awareness is necessary for early diagnosis and treatment.
Three different aspects of prosopagnosia are covered below.
In part one, neuroanatomical findings responsible for face recognition and identification in healthy subjects are described, highlighting the core and extended neural network of the extrastriate visual cortex. The three main areas in the core system are: the fusiform face area (FFA), the occipital face area (OFA), and posterior superior temporal sulcus (pSTS).
In part two, the essential clinical and diagnostic features of developmental (congenital) prosopagnosia (DP) are described. DP remains life-long during life. This prosopagnosia is often hereditary. Its prevalence is 2.5% among Caucasians.
Of interest to ophthalmologists are functional changes in individuals with DP. Subjects with DP exhibit normal visual acuity and visual fields.
Part three covers acquired prosopagnosia (AP), a defect in face recognition following focal brain damage, caused by various brain diseases: it is usually due to bilateral or unilateral occipitotemporal lesions or anterior temporal damage. A better functioning right hemisphere in patients with unilateral brain damage as the cause of AP should be considered. Neuro-ophthalmological deficits have often been diagnosed, i. e., visual field defects in 82%, color vision disturbances (achromatopsia or dyschromatopsia) in 23.3%. Of special interest to ophthalmologists are the findings in subjects’ gaze behavior. There is evidence that averted-gaze and mutual gaze-activated areas differ from those involved in face processing.
There is an ongoing debate about whether face recognition and object recognition constitute separate domains. Clarification of this issue can have important theoretical implications as face recognition is often used as a prime example of domain-specificity in mind and brain. An important source of input to this debate comes from studies of individuals with developmental prosopagnosia, suggesting that face recognition can be selectively impaired. We put the selectivity-hypothesis to test by assessing the performance of 10 subjects with developmental prosopagnosia on demanding tests of visual object processing involving both regular and degraded drawings. None of the individuals exhibited a dissociation between face and object recognition, and as a group they were significantly more affected by degradation of objects than control participants. Importantly, we also find positive correlations between the severity of the face recognition impairment and the degree of impaired performance with degraded objects. This suggests that the face and object deficits are systematically related rather than coincidental. We conclude that at present, there is no strong evidence in the literature on developmental prosopagnosia supporting domain-specific accounts of face recognition.
Deciding whether two different face photographs or voice samples are from the same person represent fundamental challenges within applied settings. To date, most research has focussed on average performance in these tests, failing to consider individual differences and within‐person consistency in responses. Here, participants completed the same face (Experiment 1) or voice matching test (Experiment 2) on two separate occasions, allowing comparison of overall accuracy across the two timepoints as well as consistency in trial‐level responses. In both experiments, participants were highly consistent in their performances. In addition, we demonstrated a large association between consistency and accuracy, with the most accurate participants also tending to be the most consistent. This is an important result for applied settings in which organisational groups of super‐matchers are deployed in real‐world contexts. Being able to reliably identify these high performers based upon only a single test informs regarding recruitment for law enforcement agencies worldwide.
To investigate face individuation (FI), a critical brain function in the human species, an oddball fast periodic visual stimulation (FPVS) approach was recently introduced (Liu‐Shuang et al., 2014). In this paradigm, an image of an unfamiliar “base” facial identity is repeated at a rapid rate F (e.g., 6 Hz) and different unfamiliar “oddball” facial identities are inserted every nth item, at a F/n rate (e.g., every 5th item, 1.2 Hz). This stimulation elicits FI responses at F/n and its harmonics (2F/n , 3F/n, etc.), reflecting neural discrimination between oddball vs. base facial identities, which is quantified in the frequency‐domain of the electroencephalogram (EEG). This paradigm, used in 20 published studies, demonstrates substantial advantages for measuring FI in terms of validity, objectivity, reliability, and sensitivity. Human intracerebral recordings suggest that this FI response originates from neural populations in the lateral inferior occipital and fusiform gyri, with a right hemispheric dominance consistent with the localization of brain lesions specifically affecting facial identity recognition (prosopagnosia). Here we summarize the contributions of the oddball FPVS framework towards understanding FI, including its (a)typical development, with early studies supporting the application of this technique to clinical testing (e.g., Autism Spectrum Disorder). This review also includes an in‐depth analysis of the paradigm’s methodology, with guidelines for designing future studies. A large‐scale group analysis compiling data across 130 observers provides insights into the oddball FPVS FI response properties. Overall, we recommend the oddball FPVS paradigm as an alternative approach to behavioral or traditional event‐related‐potential EEG measures of face individuation.
This thesis explored the influence of X-linked genes on the development of face- processing abilities. It assessed face-processing abilities in women with Turner syndrome (TS) who have just one, instead of two, X-chromosomes. Study One assessed the nature and severity of face processing deficits by applying a diverse battery of neuropsychological tests to 45,Xm and control females. Women with TS performed at below average levels in terms of face and emotion recognition (particularly fearful faces) despite processing faces in a typical configural manner. Study Two found equivalent deficits in 45,Xp women. Using Voxel Based Morphometry, Study Three found evidence for increased volume of the amygdalae and orbito-frental cortices in women with TS. Because males, like 45,X females, have a single X-chromosome, Study Four sought to identify whether there was any sexual dimorphism in face processing abilities - there was not. However, differences were found between normal males and females in terms of correlations between face and emotion recognition task performance. These differences were similar to those seen in 45,Xm compared with 45,Xp females and are consistent with the hypothesis that imprinted X-linked genes influence functional mechanisms that are relevant to social cognition. Together, the results of these studies suggest a role for X-linked genes in the typical development of face processing abilities. This role might involve the development of structures involved in social and emotional processing, including the amygdala and orbito-frontal cortices. It is suggested that affective responses to faces may have an important role in our subsequent memory for them. Ways in which issues raised by these studies could be explored further are discussed.
Introduction
Abnormalities of psychologic functioning in patients with Turner's syndrome are of interest owing to their possible relationship to the well-documented cytogenetic origin of the condition.Turner's syndrome, also known as gonadal aplasia, ovarian agenesis, and gonadal dysgenesis, was first described by Turner in 1938 and has since then been extensively studied and characterized, for example by Haddad and Wilkins, 1959, and Wilkins, 1957. The genetic defect in 80% of the cases is one in which the sex chromatin is negative and the chromosome count 45, XO, instead of the normal 46,XX. Other cases have been shown to be chromatin positive and to have XO/XX, XO/XXX, or other mosaicisms, or to have chromosome deletions or translocations.Shaffer in 1962 first called attention to a peculiar psychologic abnormality in Turner's syndrome that was associated with a Wechsler Performance IQ significantly lower than Verbal IQ. Applying Cohen's
The purpose of this research was to compare several tests requiring the recognition of unknown faces for their power to discriminate among different groups of patients with unilateral cerebral lesions. These groups were: 1) right brain-damaged patients without visual field defects (N = 31); 2) right brain-damaged patients with visual field defects (N = 19); 3) left brain-damaged patients without visual field defects (N = 50); 4) left brain-damaged patients with visual field defects (N = 14).
"62 PATIENTS WITH UNILATERAL CORTICAL LESIONS WERE GIVEN 2 TESTS OF FACIAL RECOGNITION, WHICH REQUIRED RECOGNITION OF WELL-KNOWN FACES AND RECOGNITION FROM IMMEDIATE MEMORY OF PREVIOUSLY UNKNOWN FACES. THE RIGHT HEMISPHERE GROUP WAS IMPAIRED RELATIVE TO THE LEFT HEMISPHERE GROUP ON BOTH TESTS. IN NEITHER GROUP WAS THERE A SIGNIFICANT CORRELATION BETWEEN THE SCORES ON THE 2 TASKS, INDICATING THAT THE TASKS WERE TESTS OF SEPARATE AND DISTINCT FUNCTIONS. THE RESULTS ARE DISCUSSED IN TERMS OF THE CLINICAL SYNDROME, PROSOPAGNOSIA. IT IS SUGGESTED THAT PROSOPAGNOSIA MAY BE A CONSTITUENT OF AN AMNESIC SYNDROME." (PsycINFO Database Record (c) 2012 APA, all rights reserved)
2 hemispheric groups were given 4 visuo-perceptual tests: overlapping figures, face identification, the Farnsworth 100 Hue, and objective-figure matching. The 1st 3 tests were assumed to be demanding at the apperceptive level, while the 4th was much simpler but required the comprehension of the meaning of the items. Right brain-damaged patients with visual field defects were found to be specifically impaired on the 3 apperceptive tests. Left brain-damaged patients, in turn, performed with lowest scores on the object-figure matching test. There was a highly significant correlation in the left group, but not in the right, between the performance on the matching test and that on the Weigl abstract thinking test. Almost all right hemisphere patients who achieved poor scores on the matching tests were also impaired on the apperceptive tests, while this was not the case for about 1/3 of the left hemisphere patients. These findings are suggestive of a differential specialization between the 2 hemispheres in the process of visual recognition. The bearing of these data on Lissauer's classification of visual agnosia into an apperceptive and an associative form is discussed. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
A patient with a severe disorder of visual recognition is described. In the absence of impaired “apperceptive” processes it is concluded that this is a case of associative object agnosia.
On rare occasions, the inability to identify animal faces forms a part of prosopagnosia, the inability to recognise human faces. A case is reported who showed a sudden loss of the ability to recognise acquaintances and relatives by their facial expression. This was probably the result of an embolus. An important finding was a left hemianopsia and a loss of the ability to recognise animal faces. The patient had been reared on a farm and had previously an outstanding ability to identify animal faces.
A test requiring the identification of unfamiliar faces was developed and given to groups of patients with lesions of the left or the right hemisphere as well as to a large group of control patients. Performance level in the control group showed a slight decline with age but was not related to education or sex. The mean performance levels of both brain-damaged groups were significantly inferior to that of the control group. In addition, however, the mean performance level of the patients with right hemisphere lesions was significantly inferior to that of the patients with left hemisphere lesions and grossly defective performances were made mainly by patients with right hemisphere lesions. Performance level was not related to the presence of visual field defect, the presence of aphasia, type of lesion or intrahemispheric locus of lesion. A number of considerations suggested that the observed interhemispheric difference in performance was not related to a possible difference in the extent of lesion in the two groups.
"The "developmental norms' used were compiled . . . for use with 15 neuropsychological tests with children aged 6-15. The norms were obtained by testing a randomly selected population of school children . . . . Repeaters, children with known learning or behavior problems and children with known brain dysfunctions were excluded. Tests on these 'normal' children produced an average IQ of 112 for all age groups . . . . Thus, the sample can be considered as representative for a middle-class Western Canadian school population. However, caution should be observed in applying these norms to new S populations, particularly in regard to general level of intelligence, educational and motivational status, etc. Because of the heavy emphasis on perceptual and motor functions in these tests, serious differences are not likely to occur in different geographical or social samples of the population. A comparison with Knights' . . . norms shows good agreement indeed. To our knowledge, other norms have not been made available for these tests." (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Difficulty in the recognition of faces as a symptom in patients with cerebral disease is not a new observation. It was first described by Charcot¹ in 1883 and by Wilbrand² in 1892. Case reports alluding to the phenomenon were later published by Millian,³ Hoff and Pötzl⁴ and Donini.⁵ However, it was Bodamer⁶ who definitively described the deficit in 1947 on the basis of 3 personally observed cases, and who proposed the name "prosopagnosia" for this special type of visual agnosia. Realizing that "prosopagnosia" is often merely one aspect of the clinical picture of severe object or form agnosia, Bodamer took pains to emphasize that this is not always the case and that recognition of faces may be preserved in patients with object agnosia. In this connection, he cited the cases of Lissauer⁷ and Nielsen.⁸ Ajuriaguerra and one of us (H.H.) recently observed
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