Face Processing System Research Articles

Preserved fine-tuning of face perception and memory: evidence from the own-race bias in high- and low-performing older adults

Previous research suggests specific deficits in face perception and memory in older adults, which could reflect a dedifferentiation in the context of a general broadening of cognitive architecture with advanced age. Such dedifferentiation could manifest in a less specialized face processing system. A promising tool to investigate the fine-tuning of face processing in older age is the own-race bias (ORB), a phenomenon reflecting more accurate memory for own-relative to other-race faces, which is related to an expertise-based specialization of early perceptual stages. To investigate whether poor face memory in older age is accompanied by reduced expertise-based specialization of face processing, we assessed event-related brain potential correlates of the ORB in high- vs. low-performing older adults (mean age = 69 years; N = 24 per group). Intriguingly, both older groups demonstrated an equivalent pattern of a behavioral ORB, and a parallel increase in N170 for other-race faces, reflecting less efficient early perceptual processing for this face category. Group differences only emerged independent of face ethnicity: whereas low-performers exhibited a right-lateralized N170, high-performers showed a more bilateral response. This finding may suggest a compensatory mechanism counteracting age-related decline in face perception enabling more efficient encoding into memory in high performers. Overall, our results demonstrate that even a less efficient face processing system in older adults can exhibit preserved expertise-related specialization toward own-race faces.

Accessing stored knowledge of familiar people from faces names and voices A review

Recent findings from neuropsychology and experimental psychology appear incompatible with the claim that feelings of familiarity about known people require activation of amodal person identity nodes. Evidence suggests that there are modality-specific effects after the point at which faces, names and voices have been found familiar. It therefore appears that activation of distinct modality-specific face, name and voice processing systems can signal that a known person is familiar. There is no convincing evidence, however, of modular effects on the way that information about familiar people is represented in semantic memory. Instead, semantic information about people appears to be stored separately from other forms of knowledge such as knowledge of objects. Anatomical evidence suggests that amodal person-specific semantic knowledge is stored in the right anterior temporal lobe where it has close connections with modality specific recognition systems. Failures to retrieve names in proper name anomia may be caused by impairments to the links between semantic knowledge in the right anterior temporal lobe and lexical representations in the left temporal pole.

The Other-Race Effect in Caucasian and Japanese-Descendant Children in Brazil: Evidence of Developmental Plasticity

The Other-Race Effect has been confirmed by several experimental studies, in which the individual has greater difficulty in recognizing the faces of races that are different from their own. Few studies have investigated this effect during the development of the face processing system. The aim of this study was to investigate the development of the Other-Race Effect in Caucasian and Japanese-descendants children born and living in Brazil. Seventy-four children, split into two age groups (5 - 7 and 9 - 11 years of age), were tested. Japanese-descendant children did not present the effect in favor of their own-race faces, whereas Caucasian children demonstrated the effect in both age groups. This indicates that the effect is present early in the development of face recognition and that contact with the faces of another race during childhood dissipates it. These findings suggest that experience with faces from the children’s visual context is crucial for shaping face processing.

When a loved one feels unfamiliar: A case study on the neural basis of Capgras delusion

Perception of familiar faces depends on a core system analysing visual appearance and an extended system dealing with inference of mental states and emotional responses. Damage to the core system impairs face perception as seen in prosopagnosia. In contrast, patients with Capgras delusion show intact face perception but believe that closely related persons are impostors. It has been suggested that two deficits are necessary for the delusion, an aberrant perceptual or affective experience that leads to a bizarre belief as well as an impaired ability to evaluate beliefs. Using functional magnetic resonance imaging, we compared neural activity to familiar and unfamiliar faces in a patient with Capgras delusion and an age matched control group. We provide evidence that Capgras delusion is related to dysfunctional activity in the extended face processing system. The patient, who developed the delusion for the partner after a large right prefrontal lesion sparing the ventromedial and medial orbitofrontal cortex, lacked neural activity to the partner's face in left posterior cingulate cortex and left posterior superior temporal sulcus. Further, we found impaired functional connectivity of the latter region with the left superior frontal gyrus and to a lesser extent with the right superior frontal sulcus/middle frontal gyrus. The findings of this case study suggest that the first factor in Capgras delusion may be reduced neural activity in the extended face processing system that deals with inference of mental states while the second factor may be due to a lesion in the right middle frontal gyrus.

Perception of Social Cues of Danger in Autism Spectrum Disorders

Intuitive grasping of the meaning of subtle social cues is particularly affected in autism spectrum disorders (ASD). Despite their relevance in social communication, the effect of averted gaze in fearful faces in conveying a signal of environmental threat has not been investigated using real face stimuli in adults with ASD. Here, using functional MRI, we show that briefly presented fearful faces with averted gaze, previously shown to be a strong communicative signal of environmental danger, produce different patterns of brain activation than fearful faces with direct gaze in a group of 26 normally intelligent adults with ASD compared with 26 matched controls. While implicit cue of threat produces brain activation in attention, emotion processing and mental state attribution networks in controls, this effect is absent in individuals with ASD. Instead, individuals with ASD show activation in the subcortical face-processing system in response to direct eye contact. An effect of differences in looking behavior was excluded in a separate eye tracking experiment. Our data suggest that individuals with ASD are more sensitive to direct eye contact than to social signals of danger conveyed by averted fearful gaze.

I spy with my little eye: typical, daily exposure to faces documented from a first-person infant perspective.

ABSTRACTExposure to faces is known to shape and change the face processing system; however, no study has yet documented infants' natural daily first‐hand exposure to faces. One‐ and three‐month‐old infants' visual experience was recorded through head‐mounted cameras. The video recordings were coded for faces to determine: (1) How often are infants exposed to faces? (2) To what type of faces are they exposed? and (3) Do frequently encountered face types reflect infants' typical pattern of perceptual narrowing? As hypothesized, infants spent a large proportion of their time (25%) exposed to faces; these faces were primarily female (70%), own‐race (96%), and adult‐age (81%). Infants were exposed to more individual exemplars of female, own‐race, and adult‐age faces than to male, other‐race, and child‐ or older‐adult‐age faces. Each exposure to own‐race faces was longer than to other‐race faces. There were no differences in exposure duration related to the gender or age of the face. Previous research has found that the face types frequently experienced by our participants are preferred over and more successfully recognized than other face types. The patterns of face exposure revealed in the current study coincide with the known trajectory of perceptual narrowing seen later in infancy.© 2013 The Authors. Developmental Psychobiology Published by Wiley Periodicals, Inc. Dev Psychobiol 56: 249–261, 2014.

Single-Neuron Correlates of Atypical Face Processing in Autism

People with autism spectrum disorder (ASD) show abnormal processing of faces. A range of morphometric, histological, and neuroimaging studies suggest the hypothesis that this abnormality may be linked to the amygdala. We recorded data from single neurons within the amygdalae of two rare neurosurgical patients with ASD. While basic electrophysiological response parameters were normal, there were specific and striking abnormalities in how individual facial features drove neuronal response. Compared to control patients, a population of neurons in the two ASD patients responded significantly more to the mouth, but less to the eyes. Moreover, we found a second class of face-responsive neurons for which responses to faces appeared normal. The findings confirm the amygdala's pivotal role in abnormal face processing by people with ASD at the cellular level and suggest that dysfunction may be traced to a specific subpopulation of neurons with altered selectivity for the features of faces.

Timing and tuning for familiarity of cortical responses to faces.

Different kinds of known faces activate brain areas to dissimilar degrees. However, the tuning to type of knowledge, and the temporal course of activation, of each area have not been well characterized. Here we measured, with functional magnetic resonance imaging, brain activity elicited by unfamiliar, visually familiar, and personally-familiar faces. We assessed response amplitude and duration using flexible hemodynamic response functions, as well as the tuning to face type, of regions within the face processing system. Core face processing areas (occipital and fusiform face areas) responded to all types of faces with only small differences in amplitude and duration. In contrast, most areas of the extended face processing system (medial orbito-frontal, anterior and posterior cingulate) had weak responses to unfamiliar and visually-familiar faces, but were highly tuned and exhibited prolonged responses to personally-familiar faces. This indicates that the neural processing of different types of familiar faces not only differs in degree, but is probably mediated by qualitatively distinct mechanisms.

Emotional Face Processing in Pediatric Bipolar Disorder: Evidence for Functional Impairments in the Fusiform Gyrus

Pediatric bipolar disorder involves poor social functioning, but the neural mechanisms underlying these deficits are not well understood. Previous neuroimaging studies have found deficits in emotional face processing localized to emotional brain regions. However, few studies have examined dysfunction in other regions of the face processing circuit. This study assessed hypoactivation in key face processing regions of the brain in pediatric bipolar disorder. Youth with a bipolar spectrum diagnosis (n = 20) were matched to a nonbipolar clinical group (n = 20), with similar demographics and comorbid diagnoses, and a healthy control group (n = 20). Youth participated in a functional magnetic resonance imaging (fMRI) scanning which employed a task-irrelevant emotion processing design in which processing of facial emotions was not germane to task performance. Hypoactivation, isolated to the fusiform gyrus, was found when viewing animated, emerging facial expressions of happiness, sadness, fearfulness, and especially anger in pediatric bipolar participants relative to matched clinical and healthy control groups. The results of the study imply that differences exist in visual regions of the brain's face processing system and are not solely isolated to emotional brain regions such as the amygdala. Findings are discussed in relation to facial emotion recognition and fusiform gyrus deficits previously reported in the autism literature. Behavioral interventions targeting attention to facial stimuli might be explored as possible treatments for bipolar disorder in youth.

A Priori Laplacian with Hamming Distance: Advanced Dimension Reduction Technique

Images containing faces are essential to intelligent visionbased human computer interaction, and research efforts in face processing include face recognition, face tracking, pose estimation, and expression recognition. The rapidly expanding research in face processing is based on the premise that information about a user’s identity, state, and intent can be extracted from images and that computers can then react accordingly, e.g., by knowing person’s identity, person may be authenticated to utilize a particular service or not. A first step of any face processing system is registering the locations in images where faces are present. However, face registration for whole database is a challenging task because of variability in scale, location, orientation (up-right, rotated), and pose (frontal, profile). Facial expression, occlusion, and lighting conditions also change the overall appearance of face. The Image registration algorithm will register all these images present in the database. The face recognition algorithm which is insensitive to large variation in lighting direction and facial expression is to be implemented. Taking a pattern classification approach, each pixel in an image can be considered as a coordinate in a high-dimensional space. The advantage of this is that the images of a particular face, under varying illumination but fixed pose, lie in a 3D linear subspace of the high dimensional image space—if the face is a Lambertian surface. However, since faces are not truly Lambertian surfaces and do indeed produce self-shadowing images will deviate from this linear subspace. Rather than explicitly modeling this deviation, project the image into a subspace in such a manner which discounts those regions of the face with large deviation. This is achieved by using dimension reduction techniques like Principal component analysis (PCA), Linear Discriminant analysis (LDA), Laplacian faces and other modified approaches like A Priori Laplacian and A Priori Laplacian with Hamming Distance. General Terms Face Recognition, Image Processing, Pattern Recognition

Sensitive periods for the functional specialization of the neural system for human face processing

The aim of the study was to identify possible sensitive phases in the development of the processing system for human faces. We tested the neural processing of faces in 11 humans who had been blind from birth and had undergone cataract surgery between 2 mo and 14 y of age. Pictures of faces and houses, scrambled versions of these pictures, and pictures of butterflies were presented while event-related potentials were recorded. Participants had to respond to the pictures of butterflies (targets) only. All participants, even those who had been blind from birth for several years, were able to categorize the pictures and to detect the targets. In healthy controls and in a group of visually impaired individuals with a history of developmental or incomplete congenital cataracts, the well-known enhancement of the N170 (negative peak around 170 ms) event-related potential to faces emerged, but a face-sensitive response was not observed in humans with a history of congenital dense cataracts. By contrast, this group showed a similar N170 response to all visual stimuli, which was indistinguishable from the N170 response to faces in the controls. The face-sensitive N170 response has been associated with the structural encoding of faces. Therefore, these data provide evidence for the hypothesis that the functional differentiation of category-specific neural representations in humans, presumably involving the elaboration of inhibitory circuits, is dependent on experience and linked to a sensitive period. Such functional specialization of neural systems seems necessary to archive high processing proficiency.

Varied behavioral profiles in children with developmental prosopagnosia reveal dissociations in the developing face processing system

Varied behavioral profiles in children with developmental prosopagnosia reveal dissociations in the developing face processing system

Faces in Motion: Selectivity of Macaque and Human Face Processing Areas for Dynamic Stimuli

Face recognition mechanisms need to extract information from static and dynamic faces. It has been hypothesized that the analysis of dynamic face attributes is performed by different face areas than the analysis of static facial attributes. To date, there is no evidence for such a division of labor in macaque monkeys. We used fMRI to determine specializations of macaque face areas for motion. Face areas in the fundus of the superior temporal sulcus responded to general object motion; face areas outside of the superior temporal sulcus fundus responded more to facial motion than general object motion. Thus, the macaque face-processing system exhibits regional specialization for facial motion. Human face areas, processing the same stimuli, exhibited specializations for facial motion as well. Yet the spatial patterns of facial motion selectivity differed across species, suggesting that facial dynamics are analyzed differently in humans and macaques.

Emerging Structure-Function Relations in the Developing Face Processing System

To evaluate emerging structure-function relations in a neural circuit that mediates complex behavior, we investigated age-related differences among cortical regions that support face recognition behavior and the fiber tracts through which they transmit and receive signals using functional neuroimaging and diffusion tensor imaging. In a large sample of human participants (aged 6-23 years), we derived the microstructural and volumetric properties of the inferior longitudinal fasciculus (ILF), the inferior fronto-occipital fasciculus, and control tracts, using independently defined anatomical markers. We also determined the functional characteristics of core face- and place-selective regions that are distributed along the trajectory of the pathways of interest. We observed disproportionately large age-related differences in the volume, fractional anisotropy, and mean and radial, but not axial, diffusivities of the ILF. Critically, these differences in the structural properties of the ILF were tightly and specifically linked with an age-related increase in the size of a key face-selective functional region, the fusiform face area. This dynamic association between emerging structural and functional architecture in the developing brain may provide important clues about the mechanisms by which neural circuits become organized and optimized in the human cortex.

Face recognition systems in monkey and human: are they the same thing?

Primate societies are based on face recognition. Face recognition mechanisms have been studied most extensively in humans and macaque monkeys. In both species, multiple brain areas specialized for face processing have been found, and their functional properties are characterized with increasing detail, so we can now begin to address questions about similarities and differences of face-recognition systems across species with 25 million years of separate evolution. Both systems are organized into multiple face-selective cortical areas in spatial arrangements and with functional specializations, implying both hierarchical and parallel modes of information processing. Yet open questions about homologies remain. To address these, future studies employing similar techniques and experimental designs across multiple species are needed to identify a putative core primate face processing system and to understand its differentiations into the multiple branches of the primate order.

Six-month-old infants match other-race faces with a non-native language

Early in life, infants possess an effective face-processing system which becomes specialized according to the faces present in the environment. Infants are also exposed to the voices and sounds of caregivers. Previous studies have found that face–voice associations become progressively more tuned to the types of association most prevalent in the environment. The present study investigated whether 6-month-old infants associate own-race faces with their native language and faces from a different race with a non-native language. Infants were presented with pictures of own- and other-race faces simultaneously, with a native or non-native language in a habituation paradigm. Results indicate that 6-month-olds are able to match other-race faces to a non-native language.

Are faces special to infants? An investigation of configural and featural processing for the upper and lower regions of houses in 3- to 7-month-olds

Three- to 7-month-olds were administered a house version of the Face Dimensions Test in which the featural and configural properties of the upper and lower windows were systematically varied. The Dimensions Test has previously been used to study the processing of face features and their configurations by infants (Quinn & Tanaka, 2009). Just as was the case with faces, infants were shown to be sensitive to configural change in the upper and lower regions and to featural change in the upper region, but not to featural change in the lower region. The outcomes reflect either a face processing system that can generalize broadly to stimuli that are as different from faces as houses or a more general processing system with perceptual operations that can apply to both faces and houses.

Aging Faces and Aging Perceivers: Young and Older Adults are Less Sensitive to Deviations from Normality in Older Than in Young Adult Faces

Past studies examining the other-age effect, the phenomenon in which own-age faces are recognized more accurately than other-age faces, are limited in number and report inconsistent results. Here we examine whether the perceptual system is preferentially tuned to differences among young adult faces. In experiment 1 young (18-25 years) and older adult (63-87 years) participants were shown young and older face pairs in which one member of each pair was undistorted and the other had compressed or expanded features. Participants indicated which member of each pair was more normal and which was more expanded. Both age groups were more accurate when tested with young compared with older faces-but only when judging normality. In experiment 2 we tested a separate group of young adults on the same two tasks but with upright and inverted face pairs to examine the differential pattern of results between the normality and discrimination tasks. Inversion impaired performance on the normality task but not the discrimination task and eliminated the young adult advantage in the normality task. Collectively, these results suggest that the face processing system is optimized for young adult faces and that abundant experience with older faces later in life does not reverse this perceptual tuning.

Non-verbal emotion communication training induces specific changes in brain function and structure

The perception of emotional cues from voice and face is essential for social interaction. However, this process is altered in various psychiatric conditions along with impaired social functioning. Emotion communication trainings have been demonstrated to improve social interaction in healthy individuals and to reduce emotional communication deficits in psychiatric patients. Here, we investigated the impact of a non-verbal emotion communication training (NECT) on cerebral activation and brain structure in a controlled and combined functional magnetic resonance imaging (fMRI) and voxel-based morphometry study. NECT-specific reductions in brain activity occurred in a distributed set of brain regions including face and voice processing regions as well as emotion processing- and motor-related regions presumably reflecting training-induced familiarization with the evaluation of face/voice stimuli. Training-induced changes in non-verbal emotion sensitivity at the behavioral level and the respective cerebral activation patterns were correlated in the face-selective cortical areas in the posterior superior temporal sulcus and fusiform gyrus for valence ratings and in the temporal pole, lateral prefrontal cortex and midbrain/thalamus for the response times. A NECT-induced increase in gray matter (GM) volume was observed in the fusiform face area. Thus, NECT induces both functional and structural plasticity in the face processing system as well as functional plasticity in the emotion perception and evaluation system. We propose that functional alterations are presumably related to changes in sensory tuning in the decoding of emotional expressions. Taken together, these findings highlight that the present experimental design may serve as a valuable tool to investigate the altered behavioral and neuronal processing of emotional cues in psychiatric disorders as well as the impact of therapeutic interventions on brain function and structure.

Dismantling the Face: Landscape for Another Politics?

The face is central to contemporary politics: it is photographed, pinned down, stored, documented, and presented as proof of identity in passports and ID cards. Automatic face recognition and face-processing systems are key to biopolitical control. However, Deleuze and Guattari argue that the face is a particular politics, and dismantling the face is also a politics. This paper explores what it might mean to dismantle the face, and what politics this might entail. It examines prosopagnosia, or face-blindness, as described by Oliver Sacks and exemplified by Chuck Close's paintings, which see the face as landscape. It asks whether the use of grid and screen in Close's portraits amounts to a dismantling of the face, and compares his approach to that seen in Francis Bacon's heads. It argues that Close's portraits trace a politics of becomings, a distribution of the sensible where we cannot, and do not, know who we are.