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It is well established that individuals are better at recognising faces of their own-race compared with other-races; however, there is ongoing debate regarding the perceptual mechanisms that may be involved and therefore sensitive to face-race. Here, we ask whether serial dependence of facial identity, a bias where the perception of a face's identity is biased towards a previously presented face, shows an other-race effect. Serial dependence is associated with face recognition ability and appears to operate on high-level, face-selective representations, like other candidate mechanisms (e.g., holistic processing). We therefore expected to find an other-race effect for serial dependence for our Caucasian and Asian participants. While participants showed robust effects of serial dependence for all faces, only Caucasian participants showed stronger serial dependence for own-race faces. Intriguingly, we found that individual variation in own-race, but not other-race, serial dependence was significantly associated with face recognition abilities. Preliminary evidence also suggested that other-race contact is associated with other-race serial dependence. In conclusion, though we did not find an overall difference in serial dependence for own- versus other-race faces in both participant groups, our results highlight that this bias may be functionally different for own- versus other-race faces and sensitive to racial experience.

Serial dependence is a perceptual bias where current perception is biased towards prior visual input. This bias occurs when perceiving visual attributes, such as facial identity, and has been argued to play an important functional role in vision, stabilising the perception of objects through integration. In face identity recognition, this bias could assist in building stable representations of facial identity. If so, then individual variation in serial dependence could contribute to face recognition ability. To investigate this possibility, we measured both the strength of serial dependence and the range over which individuals showed this bias (the tuning) in 219 adults, using a new measure of serial dependence of facial identity. We found that better face recognition was associated with stronger serial dependence and narrower tuning, that is, showing serial dependence primarily when sequential faces were highly similar. Serial dependence tuning was further found to be a significant predictor of face recognition abilities independently of both object recognition and face identity aftereffects. These findings suggest that the extent to which serial dependence is used selectively for similar faces is important to face recognition. Our results are consistent with the view that serial dependence plays a functional role in face recognition.

Autistic traits vary across the general population, and are linked with face recognition ability. Here we investigated potential links between autistic traits and voice recognition ability for personally familiar voices in a group of 30 listeners (15 female, 16-19 years) from the same local school. Autistic traits (particularly those related to communication and social interaction) were negatively correlated with voice recognition, such that more autistic traits were associated with fewer familiar voices identified and less ability to discriminate familiar from unfamiliar voices. In addition, our results suggest enhanced accessibility of personal semantic information in women compared to men. Overall, this study establishes a detailed pattern of relationships between voice identification performance and autistic traits in the general population.

Information about a group of similar objects can be summarized into a compressed code, known as ensemble coding. Ensemble coding of simple stimuli (e.g., groups of circles) can occur in the absence of detailed exemplar coding, suggesting dissociable processes. Here, we investigate whether a dissociation would still be apparent when coding facial identity, where individual exemplar information is much more important. We examined whether ensemble coding can occur when exemplar coding is difficult, as a result of large sets or short viewing times, or whether the two types of coding are positively associated. We found a positive association, whereby both ensemble and exemplar coding were reduced for larger groups and shorter viewing times. There was no evidence for ensemble coding in the absence of exemplar coding. At longer presentation times, there was an unexpected dissociation, where exemplar coding increased yet ensemble coding decreased, suggesting that robust information about face identity might suppress ensemble coding. Thus, for face identity, we did not find the classic dissociation-of access to ensemble information in the absence of detailed exemplar information-that has been used to support claims of distinct mechanisms for ensemble and exemplar coding.

Developmental prosopagnosia (DP) is commonly referred to as 'face blindness', a term that implies a perceptual basis to the condition. However, DP presents as a deficit in face recognition and is diagnosed using memory-based tasks. Here, we test face identification ability in six people with DP, who are severely impaired on face memory tasks, using tasks that do not rely on memory. First, we compared DP to control participants on a standardized test of unfamiliar face matching using facial images taken on the same day and under standardized studio conditions (Glasgow Face Matching Test; GFMT). Scores for DP participants did not differ from normative accuracy scores on the GFMT. Second, we tested face matching performance on a test created using images that were sourced from the Internet and so varied substantially due to changes in viewing conditions and in a person's appearance (Local Heroes Test; LHT). DP participants showed significantly poorer matching accuracy on the LHT than control participants, for both unfamiliar and familiar face matching. Interestingly, this deficit is specific to 'match' trials, suggesting that people with DP may have particular difficulty in matching images of the same person that contain natural day-to-day variations in appearance. We discuss these results in the broader context of individual differences in face matching ability.

Diagnosis of developmental or congenital prosopagnosia (CP) involves self-report of everyday face recognition difficulties, which are corroborated with poor performance on behavioural tests. This approach requires accurate self-evaluation. We examine the extent to which typical adults have insight into their face recognition abilities across four experiments involving nearly 300 participants. The experiments used five tests of face recognition ability: two that tap into the ability to learn and recognize previously unfamiliar faces [the Cambridge Face Memory Test, CFMT; Duchaine, B., & Nakayama, K. (2006). The Cambridge Face Memory Test: Results for neurologically intact individuals and an investigation of its validity using inverted face stimuli and prosopagnosic participants. Neuropsychologia, 44(4), 576-585. doi:10.1016/j.neuropsychologia.2005.07.001; and a newly devised test based on the CFMT but where the study phases involve watching short movies rather than viewing static faces-the CFMT-Films] and three that tap face matching [Benton Facial Recognition Test, BFRT; Benton, A., Sivan, A., Hamsher, K., Varney, N., & Spreen, O. (1983). Contribution to neuropsychological assessment. New York: Oxford University Press; and two recently devised sequential face matching tests]. Self-reported ability was measured with the 15-item Kennerknecht et al. questionnaire [Kennerknecht, I., Ho, N. Y., & Wong, V. C. (2008). Prevalence of hereditary prosopagnosia (HPA) in Hong Kong Chinese population. American Journal of Medical Genetics Part A, 146A(22), 2863-2870. doi:10.1002/ajmg.a.32552]; two single-item questions assessing face recognition ability; and a new 77-item meta-cognition questionnaire. Overall, we find that adults with typical face recognition abilities have only modest insight into their ability to recognize faces on behavioural tests. In a fifth experiment, we assess self-reported face recognition ability in people with CP and find that some people who expect to perform poorly on behavioural tests of face recognition do indeed perform poorly. However, it is not yet clear whether individuals within this group of poor performers have greater levels of insight (i.e., into their degree of impairment) than those with more typical levels of performance.

It has been estimated that one out of 40 people in the general population suffer from congenital prosopagnosia (CP), a neurodevelopmental disorder characterized by difficulty identifying people by their faces. CP involves impairment in recognizing faces, although the perception of non-face stimuli may also be impaired. Given that social interaction depends not only on face processing, but also on the processing of bodies, it is of theoretical importance to ascertain whether CP is also characterized by body perception impairments. Here, we tested 11 CPs and 11 matched control participants on the Body Identity Recognition Task (BIRT), a forced-choice match-to-sample task, using stimuli that require processing of body-specific, not clothing-specific, features. Results indicated that the group of CPs were as accurate as controls on the BIRT, which is in line with the lack of body perception complaints by CPs. However, the CPs were slower than controls, and when accuracy and response times were combined into inverse efficiency scores (IESs), the group of CPs were impaired, suggesting that the CPs could be using more effortful cognitive mechanisms to be as accurate as controls. In conclusion, our findings demonstrate that CP may not generally be limited to face processing difficulties, but may also extend to body perception.

There is evidence that facial expressions are perceived holistically and featurally. The composite task is a direct measure of holistic processing (although the absence of a composite effect implies the use of other types of processing). Most composite task studies have used static images, despite the fact that movement is an important aspect of facial expressions and there is some evidence that movement may facilitate recognition. We created static and dynamic composites, in which emotions were reliably identified from each half of the face. The magnitude of the composite effect was similar for static and dynamic expressions identified from the top half (anger, sadness and surprise) but was reduced in dynamic as compared to static expressions identified from the bottom half (fear, disgust and joy). Thus, any advantage in recognising dynamic over static expressions is not likely to stem from enhanced holistic processing, rather motion may emphasise or disambiguate diagnostic featural information.

Objective: Orbitofrontal cortex (OFC) damage has been associated with facial expression recognition deficits in some, but not all, previous studies. The pattern of performance of a group of patients with OFC damage was assessed across a series of facial expression recognition tasks. We aimed to determine whether some tasks were more sensitive at detecting deficits than others., Method: Seven patients with damage to the OFC, 6 control patients with frontal lesions that spared the OFC, and a group of healthy controls completed a series of facial expression recognition tasks including 2 labeling tasks and 2 matching tasks., Results: The OFC patient group demonstrated impaired labeling of negative facial expressions (i.e., anger, disgust, fear, and sadness) shown for a short time (500 ms) relative to the comparison groups. When facial expressions were shown for a longer time (5,000 ms), the OFC patient group's performance did not differ significantly from either comparison group. The OFC patient group was impaired when matching subtle, low intensity negative facial expressions, but not when matching high intensity, prototypical facial expressions., Conclusions: The pattern of performance across tasks revealed that only certain facial expression recognition tasks appear to be sufficiently sensitive to detect deficits in patients with OFC damage. These findings have important implications for the assessment of facial expression recognition difficulties in patients with OFC damage and more broadly, for special populations.

Although good tests are available for diagnosing clinical impairments in face expression processing, there is a lack of strong tests for assessing "individual differences"--that is, differences in ability between individuals within the typical, nonclinical, range. Here, we develop two new tests, one for expression perception (an odd-man-out matching task in which participants select which one of three faces displays a different expression) and one additionally requiring explicit identification of the emotion (a labelling task in which participants select one of six verbal labels). We demonstrate validity (careful check of individual items, large inversion effects, independence from nonverbal IQ, convergent validity with a previous labelling task), reliability (Cronbach's alphas of.77 and.76 respectively), and wide individual differences across the typical population. We then demonstrate the usefulness of the tests by addressing theoretical questions regarding the structure of face processing, specifically the extent to which the following processes are common or distinct: (a) perceptual matching and explicit labelling of expression (modest correlation between matching and labelling supported partial independence); (b) judgement of expressions from faces and voices (results argued labelling tasks tap into a multi-modal system, while matching tasks tap distinct perceptual processes); and (c) expression and identity processing (results argued for a common first step of perceptual processing for expression and identity).

The term covert recognition refers to recognition without awareness. In the context of face recognition, it refers to the fact that some individuals show behavioural, electrophysiological or autonomic indices of recognition in the absence of overt, conscious recognition. Originally described in cases of people that have lost their ability to overtly recognize faces (acquired prosopagnosia, AP), covert face recognition has more recently also been described in cases of congenital prosopagnosia (CP), who never develop typical overt face recognition skills. The presence of covert processing in a developmental disorder such as CP is a particularly intriguing phenomenon, and its investigation is relevant for a variety of reasons. From a theoretical point of view, it is useful to help shed light on the cognitive and neural underpinnings of face recognition deficits. From a clinical point of view, it has the potential to aid the design of rehabilitation protocols aimed at improving face recognition skills in this population. In the current review we selectively summarize the recent literature on covert face recognition in CP, highlight its main findings, and provide a theoretical interpretation for them.

The present meta-analysis aimed to clarify whether deficits in emotion recognition in psychopathy are restricted to certain emotions and modalities or whether they are more pervasive. We also attempted to assess the influence of other important variables: age, and the affective factor of psychopathy. A systematic search of electronic databases and a subsequent manual search identified 26 studies that included 29 experiments (N = 1376) involving six emotion categories (anger, disgust, fear, happiness, sadness, surprise) across three modalities (facial, vocal, postural). Meta-analyses found evidence of pervasive impairments across modalities (facial and vocal) with significant deficits evident for several emotions (i.e., not only fear and sadness) in both adults and children/adolescents. These results are consistent with recent theorizing that the amygdala, which is believed to be dysfunctional in psychopathy, has a broad role in emotion processing. We discuss limitations of the available data that restrict the ability of meta-analysis to consider the influence of age and separate the sub-factors of psychopathy, highlighting important directions for future research., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Introduction: Even though people with congenital prosopagnosia (CP) never develop a normal ability to "overtly" recognize faces, some individuals show indices of "covert" (or implicit) face recognition. The aim of this study was to demonstrate covert face recognition in CP when participants could not overtly recognize the faces., Methods: Eleven people with CP completed three tasks assessing their overt face recognition ability, and three tasks assessing their "covert" face recognition: a Forced choice familiarity task, a Forced choice cued task, and a Priming task., Results: Evidence of covert recognition was observed with the Forced choice familiarity task, but not the Priming task. In addition, we propose that the Forced choice cued task does not measure covert processing as such, but instead "provoked-overt" recognition., Conclusions: Our study clearly shows that people with CP demonstrate covert recognition for faces that they cannot overtly recognize, and that behavioural tasks vary in their sensitivity to detect covert recognition in CP., (Copyright © 2011 Elsevier Srl. All rights reserved.)

Background: Previous research suggests that many individuals with autism spectrum disorder (ASD) have impaired facial identity recognition, and also exhibit abnormal visual scanning of faces. Here, two hypotheses accounting for an association between these observations were tested: i) better facial identity recognition is associated with increased gaze time on the Eye region; ii) better facial identity recognition is associated with increased eye-movements around the face., Methodology and Principal Findings: Eye-movements of 11 children with ASD and 11 age-matched typically developing (TD) controls were recorded whilst they viewed a series of faces, and then completed a two alternative forced-choice recognition memory test for the faces. Scores on the memory task were standardized according to age. In both groups, there was no evidence of an association between the proportion of time spent looking at the Eye region of faces and age-standardized recognition performance, thus the first hypothesis was rejected. However, the 'Dynamic Scanning Index'--which was incremented each time the participant saccaded into and out of one of the core-feature interest areas--was strongly associated with age-standardized face recognition scores in both groups, even after controlling for various other potential predictors of performance., Conclusions and Significance: In support of the second hypothesis, results suggested that increased saccading between core-features was associated with more accurate face recognition ability, both in typical development and ASD. Causal directions of this relationship remain undetermined.

Empirical data regarding the extent of face recognition abnormalities in autism spectrum disorder (ASD) is inconsistent. Here, 27 ASD and 47 typically developing (TD) children completed an immediate two-alternative forced-choice identity matching task. We contrasted recognition of own- and other-race faces, and, counter to prediction, we found a typical advantage for recognizing own- over other-race faces in both the ASD and TD groups. In addition, ASD and TD groups responded similarly to stimulus manipulations (use of identical or different photographs for identity matching and cropping stimuli to remove hair information). However, age-standardized scores varied widely within the ASD sample, and a subgroup of ASD participants with impaired face recognition did not exhibit a significant own-race recognition advantage. An explanation regarding early experience with faces is considered, and implications for research of individual variation within ASD are discussed.

We test 12 individuals with congenital prosopagnosia (CP), who replicate a common pattern of showing severe difficulty in recognising facial identity in conjunction with normal recognition of facial expressions (both basic and 'social'). Strength of holistic processing was examined using standard expression composite and identity composite tasks. Compared to age- and sex-matched controls, group analyses demonstrated that CPs showed weaker holistic processing, for both expression and identity information. Implications are (a) normal expression recognition in CP can derive from compensatory strategies (e.g., over-reliance on non-holistic cues to expression); (b) the split between processing of expression and identity information may take place after a common stage of holistic processing; and (c) contrary to a recent claim, holistic processing of identity is functionally involved in face identification ability., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

The Cambridge Face Memory Test (CFMT, Duchaine & Nakayama, 2006) provides a validated format for testing novel face learning and has been a crucial instrument in the diagnosis of developmental prosopagnosia. Yet, some individuals who report everyday face recognition symptoms consistent with prosopagnosia, and are impaired on famous face tasks, perform normally on the CFMT. Possible reasons include measurement error, CFMT assessment of memory only at short delays, and a face set whose ethnicity is matched to only some Caucasian groups. We develop the "CFMT-Australian" (CFMT-Aus), which complements the CFMT-original by using ethnicity better matched to a different European subpopulation. Results confirm reliability (.88) and validity (convergent, divergent using cars, inversion effects). We show that face ethnicity within a race has subtle but clear effects on face processing even in normal participants (includes cross-over interaction for face ethnicity by perceiver country of origin in distinctiveness ratings). We show that CFMT-Aus clarifies diagnosis of prosopagnosia in 6 previously ambiguous cases. In 3 cases, this appears due to the better ethnic match to prosopagnosics. We also show that face memory at short (<3-min), 20-min, and 24-hr delays taps overlapping processes in normal participants. There is some suggestion that a form of prosopagnosia may exist that is long delay only and/or reflects failure to benefit from face repetition., (© 2011 Psychology Press, an imprint of the Taylor & Francis Group, an Informa business)

Previous research has been concerned with the relationship between social anxiety and the recognition of face expression but the question of whether there is a relationship between social anxiety and the recognition of face identity has been neglected. Here, we report the first evidence that social anxiety is associated with recognition of face identity, across the population range of individual differences in recognition abilities. Results showed poorer face identity recognition (on the Cambridge Face Memory Test) was correlated with a small but significant increase in social anxiety (Social Interaction Anxiety Scale) but not general anxiety (State-Trait Anxiety Inventory). The correlation was also independent of general visual memory (Cambridge Car Memory Test) and IQ. Theoretically, the correlation could arise because correct identification of people, typically achieved via faces, is important for successful social interactions, extending evidence that individuals with clinical-level deficits in face identity recognition (prosopagnosia) often report social stress due to their inability to recognise others. Equally, the relationship could arise if social anxiety causes reduced exposure or attention to people's faces, and thus to poor development of face recognition mechanisms.

People with congenital prosopagnosia have never developed the ability to accurately recognize faces. This single case investigation systematically investigates covert and overt face recognition in "C.," a 69 year-old woman with congenital prosopagnosia. Specifically, we: (a) describe the first assessment of covert face recognition in congenital prosopagnosia using multiple tasks; (b) show that semantic information can contribute to covert recognition; and (c) provide a theoretical explanation for the mechanisms underlying covert face recognition.

Background: The 'broader autism phenotype' (BAP) refers to the mild expression of autistic-like traits in the relatives of individuals with autism spectrum disorder (ASD). Establishing the presence of ASD traits provides insight into which traits are heritable in ASD. Here, the ability to recognise facial identity was tested in 33 parents of ASD children., Methodology and Results: In experiment 1, parents of ASD children completed the Cambridge Face Memory Test (CFMT), and a questionnaire assessing the presence of autistic personality traits. The parents, particularly the fathers, were impaired on the CFMT, but there were no associations between face recognition ability and autistic personality traits. In experiment 2, parents and probands completed equivalent versions of a simple test of face matching. On this task, the parents were not impaired relative to typically developing controls, however the proband group was impaired. Crucially, the mothers' face matching scores correlated with the probands', even when performance on an equivalent test of matching non-face stimuli was controlled for., Conclusions and Significance: Components of face recognition ability are impaired in some relatives of ASD individuals. Results suggest that face recognition skills are heritable in ASD, and genetic and environmental factors accounting for the pattern of heritability are discussed. In general, results demonstrate the importance of assessing the skill level in the proband when investigating particular characteristics of the BAP.

Facial expressions convey information about the moods and intentions of other people and provide important clues about environmental threats. Previous research has shown that patients with unilateral amygdala removals have difficulties rating the intensity of fearful facial expressions. The aim of the current study was to investigate whether patients with amygdala lesions would also be impaired at detecting fear from briefly presented, backward-masked faces. We found that patients with either left or right temporal lobe excisions were impaired at rating fear intensity in faces, whereas fear detection difficulties were predominantly seen in those who had undergone a left temporal lobectomy. Intriguingly, patients with amygdala damage found it more difficult to recognize fear from faces shown for unlimited durations than to detect fear from briefly presented faces. Moreover, there was little overlap between impairments of fear detection and fear-rating, indicating that task demands are crucially important in determining fear-processing deficits.

Adults experiencing face recognition difficulties in the absence of known brain injury are described as cases of developmental prosopagnosia (DP), under the assumption that specific face recognition impairments have always been present. However, only five childhood cases of DP have been reported, and the majority had additional socio-communicative impairments consistent with an autism spectrum disorder (ASD). We tested face recognition skills of six 4- to 8-year-old children, who were suspected of having DP, and tested for ASD using established diagnostic tools. Two children met criteria for ASD. One child did not exhibit consistent face recognition impairments. The remaining three children were severely impaired on multiple tasks of unfamiliar face recognition despite normal cognitive functioning and no evidence of ASD. Two of these children were also impaired at object recognition suggesting more general visual recognition problems. The final child showed normal object recognition demonstrating apparently specific problems with facial identity recognition.

As faces become familiar, recognition becomes easier but the style of processing also changes. Here, twenty-one typically developing (TD) children and twenty-one children with autism spectrum disorder (ASD) were familiarised with 6 identities over 3 days. Next, they completed a 4-alternative forced-choice matching test in which targets were the 6 familiarised faces and 6 unfamiliar faces. The TD group showed a significant advantage for familiarised faces when matching whole faces and both internal and external facial regions. The ASD group showed similar familiarisation effects for whole and external faces, but not for internal regions. The ASD group was also impaired at matching eyes and mouths of familiarised faces. Results suggest the process of acquiring familiarity with faces differs from ASD and TD children.

In the current report we describe a successful training study aimed at improving recognition of a set of familiar face photographs in K., a 4-year-old girl with congenital prosopagnosia (CP). A detailed assessment of K.'s face-processing skills showed a deficit in structural encoding, most pronounced in the processing of facial features within the face. In addition, eye movement recordings revealed that K.'s scan paths for faces were characterized by a large percentage of fixations directed to areas outside the internal core features (i.e., eyes, nose, and mouth), in particular by poor attendance to the eye region. Following multiple baseline assessments, training focused on teaching K. to reliably recognize a set of familiar face photographs by directing visual attention to specific characteristics of the internal features of each face. The training significantly improved K.'s ability to recognize the target faces, with her performance being flawless immediately after training as well as at a follow-up assessment 1 month later. In addition, eye movement recordings following training showed a significant change in K.'s scan paths, with a significant increase in the percentage of fixations directed to the internal features, particularly the eye region. Encouragingly, not only was the change in scan paths observed for the set of familiar trained faces, but it generalized to a set of faces that was not presented during training. In addition to documenting significant training effects, our study raises the intriguing question of whether abnormal scan paths for faces may be a common factor underlying face recognition impairments in childhood CP, an issue that has not been explored so far.

In this review we examine how attention is involved in detecting faces, recognizing facial identity and registering and discriminating between facial expressions of emotion. The first section examines whether these aspects of face perception are "automatic", in that they are especially rapid, non-conscious, mandatory and capacity-free. The second section discusses whether limited-capacity selective attention mechanisms are preferentially recruited by faces and facial expressions. Evidence from behavioral, neuropsychological, neuroimaging and psychophysiological studies from humans and single-unit recordings from primates is examined and the neural systems involved in processing faces, emotion and attention are highlighted. Avenues for further research are identified.