The Cambridge Face Memory Test: Results for neurologically intact individuals and an investigation of its validity using inverted face stimuli and prosopagnosic participants

Modular community structure of the face network supports face recognition

Face recognition is dependent on computations conducted in specialized brain regions and the communication among them, giving rise to the face-processing network. We examined whether modularity of this network may underlie the vast individual differences found in human face recognition abilities. Modular networks, characterized by strong within and weaker between-network connectivity, were previously suggested to promote efficacy and reduce interference among cognitive systems and also correlated with better cognitive abilities. The study was conducted in a large sample (n = 409) with diffusion-weighted imaging, resting-state fMRI, and a behavioral face recognition measure. We defined a network of face-selective regions and derived a novel measure of communication along with structural and functional connectivity among them. The modularity of this network was positively correlated with recognition abilities even when controlled for age. Furthermore, the results were specific to the face network when compared with the place network or to spatially permuted null networks. The relation to behavior was also preserved at the individual-edge level such that a larger correlation to behavior was found within hemispheres and particularly within the right hemisphere. This study provides the first evidence of modularity-behavior relationships in the domain of face processing and more generally in visual perception.

Neurocognitive effects of a training program for poor face recognizers using shape and texture caricatures: A pilot investigation

Recent research suggested disproportional usage of shape information by people with poor face recognition, although texture information appears to be more important for familiar face recognition. Here, we tested a training program with faces that were selectively caricatured in either shape or texture parameters. Forty-eight young adults with poor face recognition skills (1 SD below the mean in at least 2/3 face processing tests: CFMT, GFMT, BFFT) were pseudo-randomly assigned to either one of two training groups or a control group (n = 16 each). Training comprised six sessions over three weeks. Per session, participants studied ten unfamiliar facial identities whose shape or texture characteristics were caricatured. Before and after training (or waiting in the control group), all participants completed EEG experiments on face learning and famous face recognition, and behavioral face processing tests. Results showed small but specific training-induced improvements: Whereas shape training improved face matching (training tasks, and to some extent GFMT), texture training elicited marked improvements in face learning (CFMT). Moreover, for the texture training group the N170 ERP was enhanced for novel faces post-training, suggesting training-induced changes in early markers of face processing. Although further research is necessary, this suggests that parameter-specific caricature training is a promising way to improve performance in people with poor face recognition skills.

An update of the Benton Facial Recognition Test

The Benton Facial Recognition Test (BFRT) is a paper-and-pen task that is traditionally used to assess face perception skills in neurological, clinical and psychiatric conditions. Despite criticisms of its stimuli, the task enjoys a simple procedure and is rapid to administer. Further, it has recently been computerised (BFRT-c), allowing reliable measurement of completion times and the need for online testing. Here, in response to calls for repeat screening for the accurate detection of face processing deficits, we present the BFRT-Revised (BFRT-r): a new version of the BFRT-c that maintains the task's basic paradigm, but employs new, higher-quality stimuli that reflect recent theoretical advances in the field. An initial validation study with typical participants indicated that the BFRT-r has good internal reliability and content validity. A second investigation indicated that while younger and older participants had comparable accuracy, completion times were longer in the latter, highlighting the need for age-matched norms. Administration of the BFRT-r and BFRT-c to 32 individuals with developmental prosopagnosia resulted in improved sensitivity in diagnostic screening for the BFRT-r compared to the BFRT-c. These findings are discussed in relation to current diagnostic screening protocols for face perception deficits. The BFRT-r is stored in an open repository and is freely available to other researchers.

Accurate but inefficient: Standard face identity matching tests fail to identify prosopagnosia

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.

Comparing the sensitivity of face matching assessments to detect face perception impairments

Numerous neurological, developmental, and psychiatric conditions demonstrate impaired face recognition, which can be socially debilitating. These impairments can be caused by either deficient face perception or face memory mechanisms. Though there are well-validated, sensitive measures of face memory impairments, it currently remains unclear which assessments best measure face perception impairments. A sensitive, validated face perception measure could help with diagnosing causes of face recognition deficits and be useful in characterizing individual differences in unimpaired populations. Here, we compared the computerized Benton Face Recognition Test (BFRT-c) and Cambridge Face Perception Test (CFPT) in their ability to differentiate developmental prosopagnosics (DPs, N = 30) and age-matched controls (N = 30). Participants completed the BFRT-c, CFPT, and two additional face perception assessments: the University of Southern California Face Perception Test (USCFPT) and a novel same/different face matching test (SDFMT). Participants were also evaluated on objective and subjective face recognition tasks including the Cambridge Face Memory Test, famous faces test, and Prosopagnosia Index-20. We performed a logistic regression with the perception tests predicting DP vs. control group membership and used multiple linear regressions to predict continuous objective and subjective face recognition memory. Our results show that the BFRT-c performed as well as, if not better than, the CFPT, and that both tests clearly outperformed the USCFPT and SDFMT. Further, exploratory analyses revealed that face lighting-change conditions better predicted DP group membership and face recognition abilities than viewpoint-change conditions. Together, these results support the combined use of the BFRT-c and CFPT to best assess face perception impairments.

Serial dependence of facial identity for own- and other-race faces

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.

Measuring social cognition in frontotemporal lobar degeneration: a clinical approach

Alterations in social cognition, a broad term indicating our ability to understand others and adapt our behavior accordingly, have been the focus of growing attention in the past years. Some neurological conditions, such as those belonging to the frontotemporal lobar degeneration (FTLD) spectrum, are associated to varying degrees with social cognition deficits, encompassing problems with theory of mind (ToM), empathy, perception of social stimuli, and social behavior. In this review, we outline a clinical framework for the evaluation of social cognition and discuss its role in the assessment of patients affected by a range of FTLD conditions.

Face Processing in Developmental Prosopagnosia: Altered Neural Representations in the Fusiform Face Area

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.

Use of the Oxford face matching test reveals an effect of ageing on face perception but not face memory

Effects of ageing on both face perception and face memory have previously been reported. Previous studies, however, have not controlled for the effects of face perception when assessing face memory, meaning that apparent effects of ageing on face memory may actually be due to effects of ageing on face perception. Here, both face perception and face memory were assessed in a sample of adults ranging in age from 18 to 93, and the effect of age on face memory was assessed after controlling for face perception. Face perception was assessed using both a standard test and the Oxford face matching test (OFMT), deliberately designed to avoid the bias towards younger, neurotypical samples that may be present in other tests. An effect of ageing on face perception was found using both tests, with the unbiased OFMT being more sensitive to the effect of age. Importantly, when controlling for face perception using the OFMT, no effect of age on face memory was found. Indicative scores on the OFMT from a sample of 989 participants are provided, broken down by age and gender.

Individual Observer Differences in the Use of Form and Motion to Perceive the Actor's Sex in Biological Motion Displays

Recent research has shown that the perception of biological motion may be influenced by aspects of the observer's personality. In this study, we sought to determine how participant characteristics (including demographics, response inhibition, autism spectrum quotient, empathy, social anxiety, and motion imagery) might influence the use of form and motion to identify the actor's sex in biological motion displays. We varied the degree of form and motion in biological motion displays and correlated 76 young adult participants' performances for identifying the actor's sex in these varied conditions with their individual differences on variables of interest. Differences in the separate use of form and motion cues were predictive of participant performance generally, with use of form most predictive of performance. Female participants relied primarily on form information, while male participants relied primarily on motion information. Participants less able to visualize movement tended to be better at using form information in the biological motion task. Overall, our findings suggest that similar group level performances across participants in identifying the sex of the actor in a biological motion task may result from quite different individual processing.

Is human face recognition lateralized to the right hemisphere due to neural competition with left-lateralized visual word recognition? A critical review

The right hemispheric lateralization of face recognition, which is well documented and appears to be specific to the human species, remains a scientific mystery. According to a long-standing view, the evolution of language, which is typically substantiated in the left hemisphere, competes with the cortical space in that hemisphere available for visuospatial processes, including face recognition. Over the last decade, a specific hypothesis derived from this view according to which neural competition in the left ventral occipito-temporal cortex with selective representations of letter strings causes right hemispheric lateralization of face recognition, has generated considerable interest and research in the scientific community. Here, a systematic review of studies performed in various populations (infants, children, literate and illiterate adults, left-handed adults) and methodologies (behavior, lesion studies, (intra)electroencephalography, neuroimaging) offers little if any support for this reading lateralized neural competition hypothesis. Specifically, right-lateralized face-selective neural activity already emerges at a few months of age, well before reading acquisition. Moreover, consistent evidence of face recognition performance and its right hemispheric lateralization being modulated by literacy level during development or at adulthood is lacking. Given the absence of solid alternative hypotheses and the key role of neural competition in the sensory-motor cortices for selectivity of representations, learning, and plasticity, a revised language-related neural competition hypothesis for the right hemispheric lateralization of face recognition should be further explored in future research, albeit with substantial conceptual clarification and advances in methodological rigor.

The Twenty Item Prosopagnosia Index (PI20) provides meaningful evidence of face recognition impairment

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.

The effect of implicit racial bias on recognition of other-race faces

Previous research has established a possible link between recognition performance, individuation experience, and implicit racial bias of other-race faces. However, it remains unclear how implicit racial bias might influence other-race face processing in observers with relatively extensive experience with the other race. Here we examined how recognition of other-race faces might be modulated by observers’ implicit racial bias, in addition to the effects of experience and face recognition ability. Caucasian participants in a culturally diverse city completed a memory task for Asian and Caucasian faces, an implicit association test, a questionnaire assessing experience with Asians and Caucasians, and a face recognition ability test. As expected, recognition performance for Asian faces was positively predicted by increased face recognition ability, and experience with Asians. More importantly, it was also negatively predicted by increased positive bias towards Asians, which was modulated by an interaction between face recognition ability and implicit bias, with the effect of implicit bias observed predominantly in observers with high face recognition ability. Moreover, the positions of the first two fixations when participants learned the other-race faces were affected by different factors, with the first fixation modulated by the effect of experience and the second fixation modulated by the interaction between implicit bias and face recognition ability. Taken together, these findings suggest the complexity in understanding the perceptual and socio-cognitive influences on the other-race effect, and that observers with high face recognition ability may more likely evaluate racial features involuntarily when recognizing other-race faces.

Words as Visual Objects: Neural and Behavioral Evidence for High-Level Visual Impairments in Dyslexia

Developmental dyslexia is defined by reading impairments that are disproportionate to intelligence, motivation, and the educational opportunities considered necessary for reading. Its cause has traditionally been considered to be a phonological deficit, where people have difficulties with differentiating the sounds of spoken language. However, reading is a multidimensional skill and relies on various cognitive abilities. These may include high-level vision—the processes that support visual recognition despite innumerable image variations, such as in viewpoint, position, or size. According to our high-level visual dysfunction hypothesis, reading problems of some people with dyslexia can be a salient manifestation of a more general deficit of high-level vision. This paper provides a perspective on how such non-phonological impairments could, in some cases, cause dyslexia. To argue in favor of this hypothesis, we will discuss work on functional neuroimaging, structural imaging, electrophysiology, and behavior that provides evidence for a link between high-level visual impairment and dyslexia.

Face processing predicts reading ability: Evidence from prosopagnosia

There is considerable interest in whether face and word processing are reliant upon shared or dissociable processes. Developmental prosopagnosia is associated with lifelong face processing deficits, with these cases providing strong support for a dissociation between face and word recognition in three recent papers (Burns et al., 2017; Rubino et al., 2016; Starrfelt et al., 2018). However, the sample sizes in each of these studies may have been too small to detect significant effects. We therefore combined their data to increase power and reassessed their results. While only a non-significant trend for reading impairments was found in prosopagnosia using a one-sample t-test, poorer face memory performance was correlated with slower reading speeds across prosopagnosia and control participants. Surprisingly, poorer face perception skills in prosopagnosia were associated with smaller word length effects. This suggests that while mild reading impairments exist in developmental prosopagnosia, there may be a trade-off between their residual face perception abilities and reading skill. A reanalysis of Hills and colleagues' (2015) acquired prosopagnosia data also revealed a positive relationship between words and faces: severe impairments in face recognition were related to poorer word processing. In summary, the developmental and acquired prosopagnosia literature supports models of visual perception that posit face and word processing are reliant upon broadly shared processes.

Aging, pattern separation, and categorical perception of faces

Categorical perception (CP) is the phenomenon by which observers view linear changes that occur across a continuum as distinct categories. Although categorical perception is a perceptual phenomenon, it may be subserved by mnemonic processes such as pattern separation. To examine this hypothesis, following standard CP tasks, we assessed younger and older participants' abilities to identify and discriminate between members of pairs of famous or non-famous faces. We hypothesized that if CP is dependent upon neural pattern separation, which declines with aging, discrimination ability as indexed by CP would be compromised in older adults, as was found in our study. Since familiarity promotes pattern separation, CP should be enhanced for famous, as compared to non-famous faces, even in older adults. We found that all participants benefited from familiarity, but younger adults outperformed older adults overall. We next examined the effects of face inversion on CP for both famous and non-famous faces. If pattern separation, and CP, is determined solely by the similarity across physical features, then CP should be similar for upright and inverted faces since these features are perceptually invariant across orientation. If, however, pattern separation, and CP, depends on how stimuli are represented, then orientation may matter as upright and inverted faces are represented holistically or part-based, respectively. We found that inversion disrupted CP in younger adults whereas older adults performed similarly across both conditions, suggesting that face-representation is more part-based in older adults.

Implicit evidence on the dissociation of identity and emotion recognition

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.

Varying Stimulus Duration Reveals Consistent Neural Activity and Behavior for Human Face Individuation

Establishing consistent relationships between neural activity and behavior is a challenge in human cognitive neuroscience research. We addressed this issue using variable time constraints in an oddball frequency-sweep design for visual discrimination of complex images (face exemplars). Sixteen participants viewed sequences of ascending presentation durations, from 25 to 333 ms (40-3 Hz stimulation rate) while their electroencephalogram (EEG) was recorded. Throughout each sequence, the same unfamiliar face picture was repeated with variable size and luminance changes while different unfamiliar facial identities appeared every 1 s (1 Hz). A neural face individuation response, tagged at 1 Hz and its unique harmonics, emerged over the occipito-temporal cortex at 50 ms stimulus duration (25-100 ms across individuals), with an optimal response reached at 170 ms stimulus duration. In a subsequent experiment, identity changes appeared non-periodically within fixed-frequency sequences while the same participants performed an explicit face individuation task. The behavioral face individuation response also emerged at 50 ms presentation time, and behavioral accuracy correlated with individual participants' neural response amplitude in a weighted middle stimulus duration range (50-125 ms). Moreover, the latency of the neural response peaking between 180 and 200 ms correlated strongly with individuals' behavioral accuracy in this middle duration range, as measured independently. These observations point to the minimal (50 ms) and optimal (170 ms) stimulus durations for human face individuation and provide novel evidence that inter-individual differences in the magnitude and latency of early, high-level neural responses are predictive of behavioral differences in performance at this function.

Developmental prosopagnosics and super recognizers rely on the same facial features used by individuals with normal face recognition abilities for face identification

Face recognition depends on the ability of the face processing system to extract facial features that define the identity of a face. In a recent study we discovered that altering a subset of facial features changed the identity of the face, indicating that they are critical for face identification. Changing another set of features did not change the identity of a face, indicating that they are not critical for face identification. In the current study, we assessed whether developmental prosopagnosics (DPs) and super recognizers (SRs) also rely more heavily on these critical features than non-critical features for face identification. To that end, we presented to DPs and SRs faces in which either the critical or the non-critical features were manipulated. In Study 1, we presented SRs with a famous face recognition task. We found that overall SRs recognized famous faces that differ in either critical or non-critical features better than controls. Similar to controls, changes in critical features had a larger effect on SRs' face recognition than changes in non-critical features. In Study 2, we presented an identity matching task to DPs and SRs. Similar to controls, DPs and SRs perceived faces that differed in critical features as more different than faces that differed in non-critical features. Taken together, our results indicate that SRs and DPs use the same critical features for face identification as normal individuals. These findings emphasize the fundamental role of this subset of features for face identification.

Measurement of individual differences in face-identity processing abilities in older adults

BACKGROUND

Face-identity processing declines with age. Few studies have examined whether face-identity processing abilities can be measured independently from general cognitive abilities in older adults (OA). This question has practical implications for the assessment of face-identity processing abilities in OA and theoretical implications for the notion of face processing as a specific ability. The present study examined the specificity of face memory and face matching abilities in OA aged 50 + .

METHODS

Performance of younger adults (YA) and OA was measured on face tasks: Cambridge Face Memory Task (CFMT), the Glasgow Face Matching Task (GFMT), holistic processing; and tasks of general cognition: fluid intelligence, selective attention, and mental rotation. Data were analyzed using multiple regression models encompassing (i) the CFMT/GFMT and measures of general cognition; and (ii) all face processing tasks.

RESULTS

Across the two age groups, models encompassing all face tasks were significant and accounted for more variance in the data than models encompassing the CFMT/GFMT and measures of general cognition. General cognitive abilities accounted for 17% of variance for the GFMT (p < 0.01) and 3% for the CFMT (p > 0.05).

DISCUSSION

Our results suggest that face memory can be measured independently from general cognition using the CFMT in OA. Implications for the notion of a general face processing factor across the adult lifespan are discussed.

Similar use of shape and texture cues for own- and other-race faces during face learning and recognition

Although the other-race effect (ORE; superior recognition of own- relative to other-race faces) is well established, the mechanisms underlying it are not well understood. We examined whether the ORE is attributable to differential use of shape and texture cues for own- vs. other-race faces. Shape cues are particularly important for detecting that an own-race face is unfamiliar, whereas texture cues are more important for recognizing familiar and newly learned own-race faces. We compared the influence of shape and texture cues on Caucasian participants' recognition of Caucasian and East Asian faces using two complementary approaches. In Experiment 1, participants studied veridical, shape-caricatured, or texture-caricatured faces and then were asked to recognize them in an old/new recognition task. In Experiment 2, all study faces were veridical and we independently removed the diagnosticity of shape (or texture) cues in the test phase by replacing original shape (or texture) with average shape (or texture). Despite an overall own-race advantage, participants' use of shape and texture cues was comparable for own- and other-race faces. These results suggest that the other-race effect is not attributable to qualitative differences in the use of shape and texture cues.

Forgetting faces over a week: investigating self-reported face recognition ability and personality

Background

Although face recognition is now well studied, few researchers have considered the nature of forgetting over longer time periods. Here, I investigated how newly learned faces were recognised over the course of one week. In addition, I considered whether self-reported face recognition ability, as well as Big Five personality dimensions, were able to predict actual performance in a recognition task.

Methods

In this experiment (N = 570), faces were learned through short video interviews, and these identities were later presented in a recognition test (using previously unseen images) after no delay, six hours, twelve hours, one day, or seven days.

Results

The majority of forgetting took place within the first 24 hours, with no significant decrease after that timepoint. Further, self-reported face recognition abilities were moderately predictive of performance, while extraversion showed a small, negative association with performance. In both cases, these associations remained consistent across delay conditions.

Discussion

The current work begins to address important questions regarding face recognition using longitudinal, real-world time intervals, focussing on participant insight into their own abilities, and the process of forgetting more generally.

Holistic face processing is influenced by non-conscious visual information

Holistic face processing has been widely implicated in conscious face perception. Yet, little is known about whether holistic face processing occurs when faces are processed unconsciously. The present study used the composite face task and continuous flash suppression (CFS) to inspect whether the processing of target facial information (the top half of a face) is influenced by irrelevant information (the bottom half) that is presented unconsciously. Results of multiple experiments showed that the composite effect was observed in both monocular and CFS conditions, providing the first evidence that the processing of top facial halves is influenced by the aligned bottom halves no matter whether they are presented consciously or unconsciously. However, much of the composite effect for faces without masking was disrupted when bottom facial parts were rendered with CFS. These results suggest that holistic face processing can occur unconsciously, but also highlight the significance of holistic processing of consciously presented faces.

The part-whole effect in super-recognisers and typical-range-ability controls

Face recognition skills are distributed on a continuum, with developmental prosopagnosics and super-recognisers at the bottom and top ends, respectively. Holistic processing propensity is associated with face recognition ability and may be impaired in some developmental prosopagnosics and enhanced in some super-recognisers. Across two experiments we compared holistic processing of 75 super-recognisers and 89 typical-range ability controls using The Part-Whole Effect (PWE) paradigm. A subgroup of super-recognisers demonstrated enhanced PWEs in the nose region, suggesting they integrate the nose into the holistic face percept more effectively than controls. Focussed processing of the nose region, an optimal viewing position to extract the holistic properties of faces, has previously been associated with superior face recognition, and this may partly explain the superiority of some super-recognisers. However, a few super-recognisers generated extreme nose region performance patterns in an opposite direction across both experiments, suggesting their superiority is driven by alternative mechanisms. These results support proposals that super-recognition is associated with heterogeneous underlying processes.

Normal colour perception in 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.

Does Cross-Race Contact Improve Cross-Race Face Perception? A Meta-Analysis of the Cross-Race Deficit and Contact

Contact with racial outgroups is thought to reduce the cross-race recognition deficit (CRD), the tendency for people to recognize same-race (i.e., ingroup) faces more accurately than cross-race (i.e., outgroup) faces. In 2001, Meissner and Brigham conducted a meta-analysis in which they examined this question and found a meta-analytic effect of r = -.13. We conduct a new meta-analysis based on 20 years of additional data to update the estimate of this relationship and examine theoretical and methodological moderators of the effect. We find a meta-analytic effect of r = -.15. In line with theoretical predictions, we find some evidence that the magnitude of this relationship is stronger when contact occurs during childhood rather than adulthood. We find no evidence that the relationship differs for measures of holistic/configural processing compared with normal processing. Finally, we find that the magnitude of the relationship depends on the operationalization of contact and that it is strongest when contact is manipulated. We consider recommendations for further research on this topic.

Psychophysical profiles in super-recognizers

Facial identity matching ability varies widely, ranging from prosopagnosic individuals (who exhibit profound impairments in face cognition/processing) to so-called super-recognizers (SRs), possessing exceptional capacities. Yet, despite the often consequential nature of face matching decisions—such as identity verification in security critical settings—ability assessments tendentially rely on simple performance metrics on a handful of heterogeneously related subprocesses, or in some cases only a single measured subprocess. Unfortunately, methodologies of this ilk leave contributions of stimulus information to observed variations in ability largely un(der)specified. Moreover, they are inadequate for addressing the qualitative or quantitative nature of differences between SRs’ abilities and those of the general population. Here, therefore, we sought to investigate individual differences—among SRs identified using a novel conservative diagnostic framework, and neurotypical controls—by systematically varying retinal availability, bandwidth, and orientation of faces’ spatial frequency content in two face matching experiments. Psychophysical evaluations of these parameters’ contributions to ability reveal that SRs more consistently exploit the same spatial frequency information, rather than suggesting qualitatively different profiles between control observers and SRs. These findings stress the importance of optimizing procedures for SR identification, for example by including measures quantifying the consistency of individuals’ behavior.

Face memory and face perception in autism

LAY ABSTRACT

It is well known that some people with autism have difficulties recognizing faces. It is generally thought that this is not because autistic individuals cannot perceive faces, but because autistic individuals have greater problems than people without autism in remembering faces. Here, we worked with a group of autistic adults and a group of non-autistic adults to test their ability to perceive and remember faces. We also asked each person to report any difficulties that they have with recognizing faces in everyday life. We find that, as a group, people with autism have difficulties with both remembering and perceiving faces, and report more problems recognizing faces in everyday life. However, it is worth noting that we observed a wide range of scores in the group of people with autism, with some autistic participants scoring as well as the group of people without autism.

GFMT2: A psychometric measure of face matching ability

We present an expanded version of a widely used measure of unfamiliar face matching ability, the Glasgow Face Matching Test (GFMT). The GFMT2 is created using the same source database as the original test but makes five key improvements. First, the test items include variation in head angle, pose, expression and subject-to-camera distance, making the new test more difficult and more representative of challenges in everyday face identification tasks. Second, short and long versions of the test each contain two forms that are calibrated to be of equal difficulty, allowing repeat tests to be performed to examine effects of training interventions. Third, the short-form tests contain no repeating face identities, thereby removing any confounding effects of familiarity that may have been present in the original test. Fourth, separate short versions are created to target exceptionally high performing or exceptionally low performing individuals using established psychometric principles. Fifth, all tests are implemented in an executable program, allowing them to be administered automatically. All tests are available free for scientific use via www.gfmt2.org .

Visual experience modulates whole-brain connectivity dynamics: A resting-state fMRI study using the model of radiologists

Visual expertise refers to proficiency in visual recognition. It is attributed to accumulated visual experience in a specific domain and manifests in widespread neural activities that extend well beyond the visual cortex to multiple high‐level brain areas. An extensive body of studies has centered on the neural mechanisms underlying a distinctive domain of visual expertise, while few studies elucidated how visual experience modulates resting‐state whole‐brain connectivity dynamics. The current study bridged this gap by modeling the subtle alterations in interregional spontaneous connectivity patterns with a group of superior radiological interns. Functional connectivity analysis was based on functional brain segmentation, which was derived from a data‐driven clustering approach to discriminate subtle changes in connectivity dynamics. Our results showed there was radiographic visual experience accompanied with integration within brain circuits supporting visual processing and decision making, integration across brain circuits supporting high‐order functions, and segregation between high‐order and low‐order brain functions. Also, most of these alterations were significantly correlated with individual nodule identification performance. Our results implied that visual expertise is a controlled, interactive process that develops from reciprocal interactions between the visual system and multiple top‐down factors, including semantic knowledge, top‐down attentional control, and task relevance, which may enhance participants' local brain functional integration to promote their acquisition of specific visual information and modulate the activity of some regions for lower‐order visual feature processing to filter out nonrelevant visual details. The current findings may provide new ideas for understanding the central mechanism underlying the formation of visual expertise.

The Oxford Face Matching Test: A non-biased test of the full range of individual differences in face perception

Tests of face processing are typically designed to identify individuals performing outside of the typical range; either prosopagnosic individuals who exhibit poor face processing ability, or super recognisers, who have superior face processing abilities. Here we describe the development of the Oxford Face Matching Test (OFMT), designed to identify individual differences in face processing across the full range of performance, from prosopagnosia, through the range of typical performance, to super recognisers. Such a test requires items of varying difficulty, but establishing difficulty is problematic when particular populations (e.g., prosopagnosics, individuals with autism spectrum disorder) may use atypical strategies to process faces. If item difficulty is calibrated on neurotypical individuals, then the test may be poorly calibrated for atypical groups, and vice versa. To obtain items of varying difficulty, we used facial recognition algorithms to obtain face pair similarity ratings that are not biased towards specific populations. These face pairs were used as stimuli in the OFMT, and participants were required to judge whether the face images depicted the same individual or different individuals. Across five studies the OFMT was shown to be sensitive to individual differences in the typical population, and in groups of both prosopagnosic individuals and super recognisers. The test-retest reliability of the task was at least equivalent to the Cambridge Face Memory Test and the Glasgow Face Matching Test. Furthermore, results reveal, at least at the group level, that both face perception and face memory are poor in those with prosopagnosia, and are good in super recognisers.

Reflections and New Perspectives on Face Cognition as a Specific Socio-Cognitive Ability

The study of socio-cognitive abilities emerged from intelligence research, and their specificity remains controversial until today. In recent years, the psychometric structure of face cognition (FC)-a basic facet of socio-cognitive abilities-was extensively studied. In this review, we summarize and discuss the divergent psychometric structures of FC in easy and difficult tasks. While accuracy in difficult tasks was consistently shown to be face-specific, the evidence for easy tasks was inconsistent. The structure of response speed in easy tasks was mostly-but not always-unitary across object categories, including faces. Here, we compare studies to identify characteristics leading to face specificity in easy tasks. The following pattern emerges: in easy tasks, face specificity is found when modeling speed in a single task; however, when modeling speed across multiple, different easy tasks, only a unitary factor structure is reported. In difficult tasks, however, face specificity occurs in both single task approaches and task batteries. This suggests different cognitive mechanisms behind face specificity in easy and difficult tasks. In easy tasks, face specificity relies on isolated cognitive sub-processes such as face identity recognition. In difficult tasks, face-specific and task-independent cognitive processes are employed. We propose a descriptive model and argue for FC to be integrated into common taxonomies of intelligence.

The Role of Unimodal Feedback Pathways in Gender Perception During Activation of Voice and Face Areas

Cross-modal effects provide a model framework for investigating hierarchical inter-areal processing, particularly, under conditions where unimodal cortical areas receive contextual feedback from other modalities. Here, using complementary behavioral and brain imaging techniques, we investigated the functional networks participating in face and voice processing during gender perception, a high-level feature of voice and face perception. Within the framework of a signal detection decision model, Maximum likelihood conjoint measurement (MLCM) was used to estimate the contributions of the face and voice to gender comparisons between pairs of audio-visual stimuli in which the face and voice were independently modulated. Top–down contributions were varied by instructing participants to make judgments based on the gender of either the face, the voice or both modalities (N = 12 for each task). Estimated face and voice contributions to the judgments of the stimulus pairs were not independent; both contributed to all tasks, but their respective weights varied over a 40-fold range due to top–down influences. Models that best described the modal contributions required the inclusion of two different top–down interactions: (i) an interaction that depended on gender congruence across modalities (i.e., difference between face and voice modalities for each stimulus); (ii) an interaction that depended on the within modalities’ gender magnitude. The significance of these interactions was task dependent. Specifically, gender congruence interaction was significant for the face and voice tasks while the gender magnitude interaction was significant for the face and stimulus tasks. Subsequently, we used the same stimuli and related tasks in a functional magnetic resonance imaging (fMRI) paradigm (N = 12) to explore the neural correlates of these perceptual processes, analyzed with Dynamic Causal Modeling (DCM) and Bayesian Model Selection. Results revealed changes in effective connectivity between the unimodal Fusiform Face Area (FFA) and Temporal Voice Area (TVA) in a fashion that paralleled the face and voice behavioral interactions observed in the psychophysical data. These findings explore the role in perception of multiple unimodal parallel feedback pathways.

Why the other-race effect matters: Poor recognition of other-race faces impacts everyday social interactions

What happens to everyday social interactions when other-race recognition fails? Here, we provide the first formal investigation of this question. We gave East Asian international students (N = 89) a questionnaire concerning their experiences of the other-race effect (ORE) in Australia, and a laboratory test of their objective other-race face recognition deficit using the Cambridge Face Memory Test (CFMT). As a 'perpetrator' of the ORE, participants reported that their problems telling apart Caucasian people contributed significantly to difficulties socializing with them. Moreover, the severity of this problem correlated with their ORE on the CFMT. As a 'victim' of the ORE, participants reported that Caucasians' problems telling them apart also contributed to difficulties socializing. Further, 81% of participants had been confused with other Asians by a Caucasian authority figure (e.g., university tutor, workplace boss), resulting in varying levels of upset/difficulty. When compared to previously established contributors to international students' high rates of social isolation, ORE-related problems were perceived as equally important as the language barrier and only moderately less important than cultural differences. We conclude that the real-world impact of the ORE extends beyond previously identified specialized settings (eyewitness testimony, security), to common everyday situations experienced by all humans.

Mapping the Featural and Holistic Face Processing of Bad and Good Face Recognizers

Individual abilities in face recognition (good versus bad recognizers) were explored by means of event-related potentials (ERPs). The adaptation response profile of the N170 component to whole faces, eyes and mouths was used in order to highlight the crucial role of individual abilities in identity repetition processes for unfamiliar faces. The main point of this study is to underline the importance of characterizing the performance (bad or good) of the participants and to show that behaviorally selected groups might reveal neural differences. Good recognizers showed selective right hemisphere N170 repetition effects for whole faces and not for features. On the contrary, bad recognizers showed a general repetition effect not specifically related to faces and more pronounced processing for features. These findings suggest a different contribution of holistic and featural analysis in bad and good performers. In conclusion, we propose that the N170 might be used as a tool to tease apart face encoding processes as a function of individual differences.

Category-selective deficits are the exception and not the rule: Evidence from a case-series of 64 patients with ventral occipito-temporal cortex damage

The organisational principles of the visual ventral stream are still highly debated, particularly the relative association/dissociation between word and face recognition and the degree of lateralisation of the underlying processes. Reports of dissociations between word and face recognition stem from single case-studies of category selective impairments, and neuroimaging investigations of healthy participants. Despite the historical reliance on single case-studies, more recent group studies have highlighted a greater commonality between word and face recognition. Studying individual patients with rare selective deficits misses (a) important variability between patients, (b) systematic associations between task performance, and (c) patients with mild, severe and/or non-selective impairments; meaning that the full spectrum of deficits is unknown. The Back of the Brain project assessed the range and specificity of visual perceptual impairment in 64 patients with posterior cerebral artery stroke recruited based on lesion localization and not behavioural performance. Word, object, and face processing were measured with comparable tests across different levels of processing to investigate associations and dissociations across domains. We present two complementary analyses of the extensive behavioural battery: (1) a data-driven analysis of the whole patient group, and (2) a single-subject case-series analysis testing for deficits and dissociations in each individual patient. In both analyses, the general organisational principle was of associations between words, objects, and faces even following unilateral lesions. The majority of patients either showed deficits across all domains or in no domain, suggesting a spectrum of visuo-perceptual deficits post stroke. Dissociations were observed, but they were the exception and not the rule: Category-selective impairments were found in only a minority of patients, all of whom showed disproportionate deficits for words. Interestingly, such selective word impairments were found following both left and right hemisphere lesions. This large-scale investigation of posterior cerebral artery stroke patients highlights the bilateral representation of visual perceptual function.

Association of Patterns of Glaucomatous Macular Damage With Contrast Sensitivity and Facial Recognition in Patients With Glaucoma

Importance

Facial recognition is a critical activity of daily living that relies on macular function. Glaucomatous macular damage may result in impaired facial recognition that may negatively affect patient quality of life.

Objective

To evaluate the association of patterns of glaucomatous macular damage with contrast sensitivity and facial recognition among patients with glaucoma.

Design, Setting, and Participants

In this prospective cohort study at a single tertiary care center, 144 eyes of 72 consecutive patients with glaucoma with good visual acuity (20/40 or better in each eye) were studied. Data were collected from March to April 2019.

Exposures

Eyes with macular damage were categorized as having focal, diffuse, or mixed (focal and diffuse) damage based on optic disc and macular spectral-domain optical coherence tomography and 10-2 visual field (VF) damage. Only eyes with focal or diffuse damage were included. Higher-acuity and lower-acuity eyes were determined by 10-2 VF mean deviation (MD). Facial disability was defined as facial recognition scores at the 2% level of normal participants.

Main Outcomes and Measures

(1) Monocular contrast threshold as measured by the Freiburg Visual Acuity and Contrast Test and (2) binocular facial recognition as measured by the Cambridge Face Memory Test.

Results

Of the 72 included patients, 49 (68%) were White and 41 (57%) were female, and the mean (SD) age was 67.0 (11.6) years. Eyes with diffuse damage had greater contrast impairment compared with eyes with focal damage (β = -0.5; 95% CI, -0.6 to -0.4; P < .001) after adjusting for 10-2 VF MD, 24-2 VF MD, age, presence of an early cataract, and number of drops. Similarly, Cambridge Face Memory Test scores were significantly lower in patients with diffuse rather than focal macular damage, regardless of eye (better-seeing eye: β = 10.0; 95% CI, 2.0 to 18.2; P = .001; worse-seeing eye: β = 5.5; 95% CI, 0.8 to 10.0; P = .23). Relative risk of facial disability was greater for patients with diffuse but not focal macular damage in the better-seeing eye (relative risk, 86.2; 95% CI, 2.7 to 2783.3; P = .01).

Conclusions and Relevance

In this cohort study, diffuse rather than focal glaucomatous macular damage was associated with diminished facial recognition and contrast sensitivity. Evaluation of macular optical coherence tomography and 10-2 VF and resultant detection of diffuse macular damage may help minimize glaucoma-related visual disability.

Intracerebral electrical stimulation to understand the neural basis of human face identity recognition

Recognizing people's identity by their faces is a key function in the human species, supported by regions of the ventral occipito-temporal cortex (VOTC). In the last decade, there have been several reports of perceptual face distortion during direct electrical stimulation (DES) with subdural electrodes positioned over a well-known face-selective VOTC region of the right lateral middle fusiform gyrus (LatMidFG; i.e., the "Fusiform Face Area", FFA). However, transient impairments of face identity recognition (FIR) have been extremely rare and only behaviorally quantified during DES with intracerebral (i.e., depth) electrodes in stereo-electroencephalography (SEEG). The three detailed cases reported so far, summarized here, were specifically impaired at FIR during DES inside different anatomical VOTC regions of the right hemisphere: the inferior occipital gyrus (IOG) and the LatMidFG, as well as a region that lies at the heart of a large magnetic susceptibility artifact in functional magnetic resonance imaging (fMRI): the anterior fusiform gyrus (AntFG). In the first two regions, the eloquent electrode contacts were systematically associated with the highest face-selective and (unfamiliar) face individuation responses as measured with intracerebral electrophysiology. Stimulation in the right AntFG did not lead to perceptual changes but also caused an inability to remember having been presented face pictures, as if the episode was never recorded in memory. These observations support the view of an extensive network of face-selective VOTC regions subtending human FIR, with at least three critical nodes in the right hemisphere associated with differential intrinsic and extrinsic patterns of reentrant connectivity.

Impaired face recognition is associated with abnormal gray matter volume in the posterior cingulate cortex in congenital amusia

Congenital amusia is as a neurodevelopment disorder primarily defined by impairment in pitch discrimination and pitch memory. Interestingly, it has been reported that individuals with congenital amusia also exhibit deficits in face recognition (prosopagnosia). One explanation of such comorbidity is that the neural substrates of pitch recognition and face recognition may be similar. To test this hypothesis, face recognition ability was assessed using the Cambridge Face Memory Test (CFMT) and gray matter volume was determined through voxel-based morphometry (VBM) among participants with and without congenital amusia. As expected, participants with amusia performed worse on the CFMT test and showed reduced gray matter volume (GMV) in the middle temporal gyrus (MTG), the superior temporal gyrus (STG), and the posterior cingulate cortex (PCC) in the right hemisphere, when compared with matched controls. Furthermore, correlation analyses demonstrated that the CFMT score was positively related to MTG, STG, and PCC GMV in all participants, while separate analyses of each group found a positive correlation of CFMT score and PCC GMV in amusics. These findings suggest that face recognition is associated with a widely distributed microstructural network in the human brain and the PCC plays an important role in both pitch recognition and face recognition in amusics. In addition, neurodevelopmental disorders such as congenital amusia and prosopagnosia may share a common neural substrate.

The role of olfaction and sex-hormone status in empathy-related measures

Reports of a female advantage in empathy-related measures suggest a role for sex hormones, although the data are inconsistent. Studies also report similar sex differences in human olfactory perception. In rodents, olfaction is involved in detecting and integrating socially relevant information and is modulated by the brain actions of estrogens. We hypothesized that olfaction may untangle the mixed evidence on the relationship between sex hormones and empathy-related measures (cognitive and affective) in humans. To test this, we examined 60 healthy participants in three sex-hormone-status groups: free-cycling women tested in cycle phases with higher 17-β estradiol and progesterone, oral-contraceptive users (low estradiol and progesterone), and men. We assessed empathy-related measures, facial mimicry (from zygomaticus and corrugator muscle activity), and odor discrimination ability. In the empathy-related measures and facial mimicry, we did not find overall group effects or meaningful associations with salivary levels of estradiol, progesterone, or testosterone. Free-cycling women only outperformed men in the recognition of emotions from pictures of the eye region, but sex hormones were unrelated to emotion recognition performance. Oral contraceptive users showed higher scores in the affective empathy-related measure when viewing negative emotions, with no relation to hormone levels. Free-cycling women exhibited the strongest facial mimicry (viewing female, but not male protagonists), positively associated with progesterone. Finally, the groups differed in odor discrimination, with free-cycling women outperforming men. However, odor discrimination ability and empathy-related performance were not correlated. Our results support a role of sex hormones in odor perception and in empathy-related measures, to a certain extent. However, no common underlying mechanism was found.

Serial dependence of facial identity reflects high-level face coding

Serial dependence of facial identity is a type of bias where the perceived identity of a face is biased towards a previously presented face. There are individual differences in serial dependence strength and tuning (how the strength varies depending on stimuli similarity), and previous research has shown that both stronger and more narrowly tuned serial dependence of facial identity is associated with better face recognition abilities. These results are consistent with the idea that this bias plays a functional role in face perception. It is important, therefore, to determine whether serial dependence of facial identity reflects a high-level face-coding mechanism acting on the identity of a face or instead predominantly reflects a bias in low-level features, which are also subject to serial dependence. We first sought evidence that serial dependence of facial identity survived changes in low-level visual features, by varying face viewpoint between successive stimuli. We found that serial dependence persisted across changes in viewpoint, arguing against an entirely low-level locus for this bias. We next tested whether the bias was affected by inversion, as sensitivity to inversion is argued to be a characteristic of high-level face-selective processing. Serial dependence was stronger and more narrowly tuned for upright than inverted faces. Taken together, our results are consistent with the view that serial dependence of facial identity affects high-level visual representations and may reflect a face-coding mechanism that is operating at the level of facial identity.

Patterns of perceptual performance in developmental prosopagnosia: An in-depth case series

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

Associations between self-reported and objective face recognition abilities are only evident in above- and below-average recognisers

The 20-Item Prosopagnosia Items (PI-20) was recently introduced as a self-report measure of face recognition abilities and as an instrument to help the diagnosis of prosopagnosia. In general, studies using this questionnaire have shown that observers have moderate to strong insights into their face recognition abilities. However, it remains unknown whether these insights are equivalent for the whole range of face recognition abilities. The present study investigates this issue using the Mandarin version of the PI-20 and the Cambridge Face Memory Test Chinese (CFMT-Chinese). Our results showed a moderate negative association between the PI-20 and the CFMT-Chinese. However, this association was driven by people with low and high face recognition ability, but absent in people within the typical range of face recognition performance. The implications of these results for the study of individual differences and the diagnosis of prosopagnosia are discussed.

Typically Efficient Lipreading without Motor Simulation

All it takes is a face-to-face conversation in a noisy environment to realize that viewing a speaker's lip movements contributes to speech comprehension. What are the processes underlying the perception and interpretation of visual speech? Brain areas that control speech production are also recruited during lipreading. This finding raises the possibility that lipreading may be supported, at least to some extent, by a covert unconscious imitation of the observed speech movements in the observer's own speech motor system-a motor simulation. However, whether, and if so to what extent, motor simulation contributes to visual speech interpretation remains unclear. In two experiments, we found that several participants with congenital facial paralysis were as good at lipreading as the control population and performed these tasks in a way that is qualitatively similar to the controls despite severely reduced or even completely absent lip motor representations. Although it remains an open question whether this conclusion generalizes to other experimental conditions and to typically developed participants, these findings considerably narrow the space of hypothesis for a role of motor simulation in lipreading. Beyond its theoretical significance in the field of speech perception, this finding also calls for a re-examination of the more general hypothesis that motor simulation underlies action perception and interpretation developed in the frameworks of motor simulation and mirror neuron hypotheses.