Holistic face processing is mature at 4 years of age: Evidence from the composite face effect

Robust holistic face processing in early childhood during the COVID-19 pandemic

The timing of the developmental emergence of holistic face processing and its sensitivity to experience in early childhood are somewhat controversial topics. To investigate holistic face perception in early childhood, we used an online testing platform and administered a two-alternative forced-choice task to 4-, 5-, and 6-year-old children. The children saw pairs of composite faces and needed to decide whether the faces were the same or different. To determine whether experience with masked faces may have negatively affected holistic processing, we also administered a parental questionnaire to assess the children's exposure to masked faces during the COVID-19 pandemic. We found that all three age groups performed holistic face processing when the faces were upright (Experiment 1) but not when the faces were inverted (Experiment 2), that response accuracy increased with age, and that response accuracy was not related to degree of exposure to masked faces. These results indicate that holistic face processing is relatively robust in early childhood and that short-term exposure to partially visible faces does not negatively affect young children's holistic face perception.

The impact of face masks on infants' learning of faces: An eye tracking study

This preregistered study examined how face masks influenced face memory in a North American sample of 6- to 9-month-old infants (N = 58) born during the COVID-19 pandemic. Infants' memory was tested using a standard visual paired comparison (VPC) task. We crossed whether or not the faces were masked during familiarization and test, yielding four trial types (masked-familiarization/masked-test, unmasked-familiarization/masked-test, masked-familiarization/unmasked-test, and unmasked-familiarization/unmasked-test). Infants showed memory for the faces if the faces were unmasked at test, regardless of whether or not the face was masked during familiarization. However, infants did not show robust evidence of memory when test faces were masked, regardless of the familiarization condition. In addition, infants' bias for looking at the upper (eye) region was greater for masked than unmasked faces, although this difference was unrelated to memory performance. In summary, although the presence of face masks does appear to influence infants' processing of and memory for faces, they can form memories of masked faces and recognize those familiar faces even when unmasked.

Holistic face processing in 4- and 7-month-old infants

Previous studies found an onset of holistic face processing in the age range between 0-4 and 7 months of age. To validate these studies, the present study investigated infants 4 and 7 months of age with a different experimental approach. In a habituation-dishabituation experiment, the infants were tested with stereoscopic stimuli in which stripes floated above a face, thereby occluding some parts of the face (amodal completion condition), and stereoscopic stimuli in which the same face parts floated above stripes (modal completion condition). Research with adults indicates that faces are processed holistically, that is as global wholes, in the amodal, but as independent parts in the modal completion condition, resulting in superior face recognition when the occluding bars are in front of than when they are behind the visible face parts. The present study found that infants regardless of whether they are 4 or 7 months old reliably recognized and differentiated the faces in the amodal but not in the modal completion condition. Moreover, the difference between the experimental conditions was statistically significant. These findings show that approximately at the age of 4-7 months of life, infants begin to holistically unify disjoint face parts into a coherent whole.

Developmental trajectories of expert perception processing of Chinese characters in primary school children

Previous studies have demonstrated that inversion effect and left-side bias are stable expertise markers in Chinese character processing among adults. However, it is less clear how these markers develop early on (i.e., among primary school students). Therefore, this study aimed to investigate the development of the two markers by comparing primary school-aged students of three age groups (Grade 1, Grade 3, and Grade 5) and adults in tests of inversion effect (Experiment 1) and left-sided bias effect (Experiment 2). The results replicated that both effects during Chinese character processing were present among adults. However, more importantly, the effects were different among primary school-aged students in different grades: the inversion effect was found as early as in Grade 1, but the left-side bias effect did not emerge in Grade 1 and as approximated that of adults until Grade 3. The study suggested a potential dissociation in developing different aspects of expertise during Chinese character processing in early childhood.

Face masks disrupt holistic processing and face perception in school-age children

Face perception is considered a remarkable visual ability in humans that is subject to a prolonged developmental trajectory. In response to the COVID-19 pandemic, mask-wearing has become mandatory for adults and children alike. Recent research shows that mask-wearing hinders face recognition abilities in adults, but it is unknown if the same holds true in school-age children in whom face perception is not fully developed. Here we tested children (n = 72, ages 6-14 years old) on the Cambridge Face Memory Test - Kids (CFMT-K), a validated measure of face perception performance. Faces were presented with or without masks and across two orientations (upright/inverted). The inclusion of face masks led to a profound deficit in face perception abilities. This decrement was more pronounced in children compared to adults, but only when task difficulty was adjusted across the two age groups. Additionally, children exhibited reliable correlations between age and the CFMT-K score for upright faces for both the mask and no-mask conditions. Finally, as previously observed in adults, children also showed qualitative differences in the processing of masked versus non-masked faces. Specifically, holistic processing, a hallmark of face perception, was disrupted for masked faces as suggested by a reduced face-inversion effect. Together, these findings provide evidence for substantial quantitative and qualitative alterations in the processing of masked faces in school-age children.

The Composite Face Effect Between Young and Older Chinese Adults Remains Stable

Holistic face perception is often considered to be a cornerstone of face processing. However, the development of the ability to holistically perceive faces in East Asian individuals is unclear. Therefore, we measured and compared holistic face processing in groups of Chinese children, young adults, and older adults by employing the complete composite face paradigm. The results demonstrate a similar magnitude of the composite effect in all three groups although face recognition performance in the task was better in young adults than in the two other groups. These findings suggest that holistic face perception in Eastern individuals is stable from late childhood to at least age 60, whereas face memory may be subject to later development and earlier decline.

Homogenization of face neural representation during development

Extensive studies have demonstrated that face processing ability develops gradually during development until adolescence. However, the underlying mechanism is unclear. One hypothesis is that children and adults represent faces in qualitatively different fashions with different group templates. An alternative hypothesis emphasizes the development as a quantitative change with a decrease of variation in representations. To test these hypotheses, we used between-participant correlation to measure activation pattern similarity both within and between late-childhood children and adults. We found that activation patterns for faces in the fusiform face area and occipital face area were less similar within the children group than within the adults group, indicating children had a greater variation in representing faces. Interestingly, the activation pattern similarity of children to their own group template was not significantly larger than that to adults' template, suggesting children and adults shared a template in representing faces. Further, the decrease in representation variance was likely a general principle in the ventral visual cortex, as a similar result was observed in a scene-selective region when perceiving scenes. Taken together, our study provides evidence that development of object representation may result from a homogenization process that shifts from greater variance in late-childhood to homogeneity in adults.

Children process faces holistically with the same efficiency as adults

Previous studies had reported qualitatively identical holistic face processing (using the composite task) already in 6-year-olds. In the present study, we evaluated these processes quantitatively by evaluating whether children are less efficient in dealing with and encoding faces. Thus, in the present study we explored the time course of holistic processing in children and adults by manipulating stimulus presentation time. The study composite task was presented for 800 ms. The test composite face was presented either for 183 ms or 800 ms. Our youngest participants, 6-year-olds, process faces holistically with the same efficiency as typical adults.

Children are sensitive to mutual information in intermediate-complexity face and non-face features

Understanding developmental changes in children's use of specific visual information for recognizing object categories is essential for understanding how experience shapes recognition. Research on the development of face recognition has focused on children's use of low-level information (e.g. orientation sub-bands), or high-level information. In face categorization tasks, adults also exhibit sensitivity to intermediate complexity features that are diagnostic of the presence of a face. Do children also use intermediate complexity features for categorizing faces and objects, and, if so, how does their sensitivity to such features change during childhood? Intermediate-complexity features bridge the gap between low- and high-level processing: they have computational benefits for object detection and segmentation, and are known to drive neural responses in the ventral visual system. Here, we have investigated the developmental trajectory of children's sensitivity to diagnostic category information in intermediate-complexity features. We presented children (5–10 years old) and adults with image fragments of faces (Experiment 1) and cars (Experiment 2) varying in their mutual information, which quantifies a fragment's diagnosticity of a specific category. Our goal was to determine whether children were sensitive to the amount of mutual information in these fragments, and if their information usage is different from adults. We found that despite better overall categorization performance in adults, all children were sensitive to fragment diagnosticity in both categories, suggesting that intermediate representations of appearance are established early in childhood. Moreover, children's usage of mutual information was not limited to face fragments, suggesting the extracting intermediate-complexity features is a process that is not specific only to faces. We discuss the implications of our findings for developmental theories of face and object recognition.

Children's use of local and global visual features for material perception

Adults can rapidly recognize material properties in natural images, and children's performance in material categorization tasks suggests that this ability develops slowly during childhood. In the current study, we further examined the information children use to recognize materials during development by asking how the use of local versus global visual features for material perception changes in middle childhood. We recruited adults and 5- to 10-year-old children for three experiments that required participants to distinguish between shape-matched images of real and artificial food. Accurate performance in this task requires participants to distinguish between a wide range of material properties characteristic of each category, thus testing material perception abilities broadly. In two tasks, we applied distinct methods of image scrambling (block scrambling and diffeomorphic scrambling) to parametrically disrupt global appearance while preserving features in small spatial neighborhoods. In the third task, we used image blurring to parametrically disrupt local feature visibility. Our key question was whether or not participant age affected performance differently when local versus global appearance was disrupted. We found that although image blur led to disproportionately poorer performance in young children, this effect was reduced or absent when diffeomorphic scrambling was used. We interpret this outcome as evidence that the ability to recruit large-scale visual features for material perception may develop slowly during middle childhood.

Premature birth affects visual body representation and body schema in preterm children

Research has demonstrated that from the first six months of life infants show early sensitivity to body visual features and rely on sensorimotor and proprioceptive inputs in forming representations of their own bodies. Premature birth interferes with typical exposition to visual, sensorimotor and proprioceptive stimulation, thus presumably affecting the development of body representations. Here, we tested this hypothesis by comparing the performance of preterm children with that of age-matched full-termchildren in two tasks assessing, respectively, visual body processing and body schema. We found that preterm children had spared configural processing but altered holistic processing of others' bodies and showed a general difficulty in expressing visuospatial judgements on body stimuli. Furthermore, body-centered visuospatial abilities were associated with specific impairments in operating object-based visuospatial transformations. The findings of this study indicate that preterm birth might interfere with the development of body representations at the levels of body visual perceptual processing and of body schema, with effects even on visuo-spatial abilities for non-bodily stimuli. Body-centered rehabilitative interventions should be proposed to preterm children in order to enhance visuo-spatial abilities and higher-level cognitive functions.

Development of Holistic Face Processing From Childhood and Adolescence to Young Adulthood in Chinese Individuals

Previous studies have indicated that holistic face processing is important for the development of face perception. The purpose of this study was to verify the development trajectory of holistic processing, from older childhood to young adulthood, using the complete composite paradigm. Participants from three different age groups (children, adolescents, young adults) were recruited for this study. The results showed that all groups demonstrated the composite effect with similar magnitude. Furthermore, face processing performance improved with age. These results, together with previous results, imply it is a race-general phenomenon that holistic face processing is similar among older children, adolescents, and young adults.

Perception of dynamic facial expressions of emotion between dogs and humans

Facial expressions are a core component of the emotional response of social mammals. In contrast to Darwin's original proposition, expressive facial cues of emotion appear to have evolved to be species-specific. Faces trigger an automatic perceptual process, and so, inter-specific emotion perception is potentially a challenge; since observers should not try to “read” heterospecific facial expressions in the same way that they do conspecific ones. Using dynamic spontaneous facial expression stimuli, we report the first inter-species eye-tracking study on fully unrestrained participants and without pre-experiment training to maintain attention to stimuli, to compare how two different species living in the same ecological niche, humans and dogs, perceive each other’s facial expressions of emotion. Humans and dogs showed different gaze distributions when viewing the same facial expressions of either humans or dogs. Humans modulated their gaze depending on the area of interest (AOI) being examined, emotion, and species observed, but dogs modulated their gaze depending on AOI only. We also analysed if the gaze distribution was random across AOIs in both species: in humans, eye movements were not correlated with the diagnostic facial movements occurring in the emotional expression, and in dogs, there was only a partial relationship. This suggests that the scanning of facial expressions is a relatively automatic process. Thus, to read other species’ facial emotions successfully, individuals must overcome these automatic perceptual processes and employ learning strategies to appreciate the inter-species emotional repertoire.

Early Brain Damage Affects Body Schema and Person Perception Abilities in Children and Adolescents with Spastic Diplegia

Early brain damage leading to cerebral palsy is associated to core motor impairments and also affects cognitive and social abilities. In particular, previous studies have documented specific alterations of perceptual body processing and motor cognition that are associated to unilateral motor deficits in hemiplegic patients. However, little is known about spastic diplegia (SpD), which is characterized by motorial deficits involving both sides of the body and is often associated to visuospatial, attentional, and social perception impairments. Here, we compared the performance of a sample of 30 children and adolescents with SpD (aged 7-18 years) and of a group of age-matched controls with typical development (TD) at two different tasks tapping on body representations. In the first task, we tested visual and motor imagery abilities as assessed, respectively, by the object-based mental rotation of letters and by the first-person transformations for whole-body stimuli. In the second task, we administered an inversion effect/composite illusion task to evaluate the use of configural/holistic processing of others' body. Additionally, we assessed social perception abilities in the SpD sample using the NEPSY-II battery. In line with previously reported visuospatial deficits, a general mental imagery impairment was found in SpD patients when they were engaged in both object-centered and first-person mental transformations. Nevertheless, a specific deficit in operating an own-body transformation emerged. As concerns body perception, while more basic configural processing (i.e., inversion effect) was spared, no evidence for holistic (i.e., composite illusion) body processing was found in the SpD group. NEPSY-II assessment revealed that SpD children were impaired in both the theory of mind and affect recognition subtests. Overall, these findings suggested that early brain lesions and biased embodied experience could affect higher-level motor cognition and perceptual body processing, thus pointing to a strict link between motor deficits, body schema alterations, and person processing difficulties.

Neural Sensitivity to Mutual Information in Intermediate-Complexity Face Features Changes during Childhood

One way in which face recognition develops during infancy and childhood is with regard to the visual information that contributes most to recognition judgments. Adult face recognition depends on critical features spanning a hierarchy of complexity, including low-level, intermediate, and high-level visual information. To date, the development of adult-like information biases for face recognition has focused on low-level features, which are computationally well-defined but low in complexity, and high-level features, which are high in complexity, but not defined precisely. To complement this existing literature, we examined the development of children's neural responses to intermediate-level face features characterized using mutual information. Specifically, we examined children's and adults' sensitivity to varying levels of category diagnosticity at the P100 and N170 components. We found that during middle childhood, sensitivity to mutual information shifts from early components to later ones, which may indicate a critical restructuring of face recognition mechanisms that takes place over several years. This approach provides a useful bridge between the study of low- and high-level visual features for face recognition and suggests many intriguing questions for further investigation.

The development of holistic face processing: An evaluation with the complete design of the composite task

The composite paradigm is widely used to quantify holistic processing (HP) of faces: participants perform a sequential same-different task on one half (e.g., top) of a test-face relative to the corresponding half of a study-face. There is, however, debate regarding the appropriate design in this task. In the partial design, the irrelevant halves (e.g., bottom) of test- and study-faces are always different; an alignment effect indexes HP. In the complete design, besides alignment, congruency between the irrelevant and critical halves of the test-face is manipulated regarding the same/different response status of the study-face. The HP indexed in the complete design does not confound congruency and alignment and has good construct and convergent validities. De Heering, Houthuys, & Rossion (2007) argued that HP is mature as early as 4-year-olds but employed the partial design. Here we revisit this claim, testing four groups of 4- to 9/10 year-old children and two groups of adults. We found evidence of HP only from 6-year-olds on when considering the complete design, whereas significant alignment effects were found in the index adopted in the partial design already in 4-year-olds but which we demonstrate that reflects other factors besides HP, including response bias associated with congruency.

Visual perception and spatial transformation of the body in children and adolescents with brain tumor

Representations of own and others' body play a crucial role in social interaction. While extensive knowledge has been gathered on the neuropsychological deficits affecting body representation in adult brain lesion patients, little is known on how acquired damage to a developing brain may affect this process. We tested it on pediatric brain tumor survivors, comparing the abilities of 30 children and adolescents (aged 8-16 years) surviving from a supratentorial tumor (STT) or an infratentorial tumor (ITT) in two different tasks of body representation. Thirty children with typical development (TD) served as control group. In the first task, we tested configural (body inversion effect) and holistic (composite illusion effect) processing of others' bodies. In the second task, we tested the ability to perform first-person and object-based mental spatial transformations of own body and external objects, respectively. Configural processing was spared in all patients. Conversely, ITT, but not STT patients, were impaired in the holistic processing of body stimuli. STT patients performed overall worse than both controls and ITT patients at mental spatial transformations of both own body and external objects. ITT children presented selective alteration in using the first-person transformation strategies with body stimuli. Results suggest that body-representation abilities may be heavily affected in pediatric brain tumor survivors. STTs may be associated to greater difficulties in mental visuo-spatial transformation abilities, likely reflecting damage to fronto-parietal circuits. Conversely, ITTs may be associated to specific disturbances of visual body perception abilities that require motor simulation processes, reflecting direct or indirect damage to cerebellar areas.

Left-Side Bias Is Observed in Sequential Matching Paradigm for Face Processing

The left-side bias refers to how a chimeric face is created from the left side of a face (from the viewer’s perspective) and its mirror image are considered more similar to the original face than a chimeric face created from the right side of the same face and its mirror image. Previous studies investigated the left-side bias by using the chimeric stimuli task, where the original face and chimeric face were presented simultaneously. However, it remains unclear whether left-side bias effect is observed when the original face and chimeric face are presented sequentially. We completed two experiments using the sequential matching paradigm to investigate this issue. The results from both Experiment 1 and 2 showed that participants judged the identical proportion of the left chimeric face and original face was significantly higher than that of the right chimeric face and original face, which implies that the left-side bias effect can be observed in the sequential matching paradigm for face processing.

Adults’ Markers of Face Processing Are Present at Age 6 and Are Interconnected Along Development

Recent studies on the development of face processing argue for a late, quantitative, domain-specific development of face processing, and face memory in particular. Most previous findings were based on separately tracking the developmental course of face perception skills, comparing performance across different age groups. Here, we adopted a different approach studying the mechanisms underlying the development of face processing by focusing on how different face skills are interrelated over the years (age 6 to adulthood). Specifically, we examined correlations within and between different categories of tasks: face domain-specific skills involving face recognition based on long-term representations (famous face), and short-term memory retention (Cambridge Face Memory Test), perceptual face-specific marker (inversion effect), global effects in scene perception (global–local task), and the perception of facial expressions. Factor analysis revealed that face identity skills have a similar pattern of interrelations throughout development, identifying two factors: a face domain-specific factor comprising adultlike markers of face processing and a general factor incorporating related, but nonspecific perceptual skills. Domain-specific age-related changes in face recognition entailing short- and long-term retention of face representations were observed, along with mature perceptual face-specific markers and more general perceptual effects predicting face perception skills already at age 6. The results suggest that the domain-specific changes in face processing are unlikely to result from developmental changes in perceptual skills driving face recognition. Instead, development may either involve improvement in the ability to retain face representations in memory or changes in the interactions between the perceptual representations of faces and their representations in long-term memory.

Configural face perception in childhood and adolescence: An individual differences approach

Cognitive experimental and neuroscientific research in adults indicates that an important property of face perception is its specificity and reliance on configural processing. In addition, individual differences in face perception between adults cannot be entirely explained through general cognitive functioning and object cognition. Although recent years have witnessed growing interest in the development of face perception through childhood and adolescence, as yet, little is known about individual differences in configural face perception in this period of life, and whether these differences are face-specific. Here, we addressed these questions in a large sample (N = 338) drawn continuously from age six to 21. We applied a face composite task and a spatial manipulation task including stimulus inversion. Immediate and delayed face memory were assessed as covariates of configural face perception. Content specificity in configural face perception was tested by analogous tasks with houses as stimuli. In addition, we measured working memory and fluid intelligence. Our results show that there are large individual differences in configural face perception across the entire age range from six to 21 years. Supporting theories of early maturation, configural face perception was almost adult-like already at age six. Individual differences in configural face perception were related with immediate and delayed face memory and fluid intelligence across the whole age range. In sum, we provide novel evidence on large individual differences in configural face and object perception already in middle childhood, complementing findings from aging studies and providing new perspectives for further research.

Faces in early visual environments are persistent not just frequent

The regularities in very young infants' visual worlds likely have out-sized effects on the development of the visual system because they comprise the first-in experience that tunes, maintains, and specifies the neural substrate from low-level to higher-level representations and therefore constitute the starting point for all other visual learning. Recent evidence from studies using head cameras suggests that the frequency of faces available in early infant visual environments declines over the first year and a half of life. The primary question for the present paper concerns the temporal structure of face experiences: Is frequency the key exposure dimension distinguishing younger and older infants' face experiences, or is it the duration for which faces remain in view? Our corpus of head-camera images collected as infants went about their daily activities consisted of over a million individually coded frames sampled at 0.2 Hz from 232 h of infant-perspective scenes, recorded from 51 infants aged 1 month to 15 months. The major finding from this corpus is that very young infants (1-3 months) not only have more frequent face experiences but also more temporally persistent ones. The repetitions of the same very few face identities presenting up-close and frontal views are exaggerated in more persistent runs of the same face, and these persistent runs are more frequent for the youngest infants. The implications of early experiences consisting of extended repeated exposures of up-close frontal views for visual learning are discussed.

Holistic processing in mother's face perception for infants

In this study, we created composite faces using mothers' faces to examine holistic face processing in infants aged 5-8 months. The composite-face effect occurred only in infants aged 7-8 months, suggesting that infants older than 7 months are able to process familiar faces holistically.

Comparing the face inversion effect in crows and humans

Humans show impaired recognition of faces that are presented upside down, a phenomenon termed face inversion effect, which is thought to reflect the special relevance of faces for humans. Here, we investigated whether a phylogenetically distantly related avian species, the carrion crow, with similar socio-cognitive abilities to human and non-human primates, exhibits a face inversion effect. In a delayed matching-to-sample task, two crows had to differentiate profiles of crow faces as well as matched controls, presented both upright and inverted. Because crows can discriminate humans based on their faces, we also assessed the face inversion effect using human faces. Both crows performed better with crow faces than with human faces and performed worse when responding to inverted pictures in general compared to upright pictures. However, neither of the crows showed a face inversion effect. For comparative reasons, the tests were repeated with human subjects. As expected, humans showed a face-specific inversion effect. Therefore, we did not find any evidence that crows-like humans-process faces as a special visual stimulus. Instead, individual recognition in crows may be based on cues other than a conspecific's facial profile, such as their body, or on processing of local features rather than holistic processing.

Dissociated neural basis of two behavioral hallmarks of holistic face processing: The whole-part effect and composite-face effect

It has been long proposed that our extraordinary face recognition ability stems from holistic face processing. Two widely-used behavioral hallmarks of holistic face processing are the whole-part effect (WPE) and composite-face effect (CFE). However, it remains unknown whether these two effects reflect similar or different aspects of holistic face processing. Here we investigated this question by examining whether the WPE and CFE involved shared or distinct neural substrates in a large sample of participants (N=200). We found that the WPE and CFE showed hemispheric dissociation in the fusiform face area (FFA), that is, the WPE was correlated with face selectivity in the left FFA, while the CFE was correlated with face selectivity in the right FFA. Further, the correlation between the WPE and face selectivity was largely driven by the FFA response to faces, whereas the association between the CFE and face selectivity resulted from suppressed response to objects in the right FFA. Finally, we also observed dissociated correlation patterns of the WPE and CFE in other face-selective regions and across the whole brain. These results suggest that the WPE and CFE may reflect different aspects of holistic face processing, which shed new light on the behavioral dissociations of these two effects demonstrated in literature.

From development to aging: Holistic face perception in children, younger and older adults

Few published reports examine the development of holistic face processing across the lifespan such that face-specific processes are adequately differentiated from general developmental effects. To address this gap in the literature, we used the complete design of the composite paradigm (Richler & Gauthier, 2014) with faces and non-face control objects (watches) to investigate holistic processing in children (8-10years), young adults (20-32years) and older adults (65-78years). Several modifications to past research designs were introduced to improve the ability to draw conclusions about the development of holistic processing in terms of face-specificity, response bias, and age-related differences in attention. Attentional focus (narrow vs. wide focus at study) influenced the magnitude of the composite effect without eliminating holistic face processing in all age groups. Young adults showed large composite effects for faces, but none for watches. In contrast, older adults and children showed composite effects for both faces and watches, although the effects for faces were larger. Our findings suggest that holistic processing, as measured by the composite effect, might be moderated by less efficient attentional control in children and older adults. The study also underscores the importance of including comparable complex objects when investigating face processing across the lifespan.

[Recognition of facial expressions of emotions by 3-year-olds depending on sleep and risk of depression]

INTRODUCTION

The emotional process is characterized by a negative bias in depression, thus it was legitimate to establish if they same is true in very young at-risk children. Furthermore, sleep, also proposed as a marker of the depression risk, is closely linked in adults and adolescents with emotions. That is why we wanted first to better describe the characteristics of emotional recognition by 3-year-olds and their links with sleep. Secondly we observed, if found at this young age, an emotional recognition pattern indicating a vulnerability to depression.

MATERIAL AND METHOD

We studied, in 133 children aged 36 months from the AuBE cohort, the number of correct answers to the task of recognition of facial emotions (joy, anger and sadness). Cognitive functions were also assessed by the WPPSI III at 3 years old, and the different sleep parameters (time of light off and light on, sleep times, difficulty to go to sleep and number of parents' awakes per night) were described by questionnaires filled out by mothers at 6, 12, 18, 24 and 36 months after birth. Of these 133 children, 21 children whose mothers had at least one history of depression (13 boys) were the high-risk group and 19 children (8 boys) born to women with no history of depression were the low-risk group (or control group).

RESULTS

Overall, 133 children by the age of 36 months recognize significantly better happiness than other emotions (P=0.000) with a better global recognition higher in girls (M=8.8) than boys (M=7.8) (P=0.013) and a positive correlation between global recognition ability and verbal IQ (P=0.000). Children who have less daytime sleep at 18 months and those who sleep less at 24 months show a better recognition of sadness (P=0.043 and P=0.042); those with difficulties at bedtime at 18 months recognize less happiness (P=0.043), and those who awaken earlier at 24 months have a better global recognition of emotions (P=0.015). Finally, the boys of the high-risk group recognize sadness better than boys in the control group (P=0.015).

CONCLUSION

This study confirms that the recognition of emotion is related to development with a female advantage and a link with the language skills at 36 months of life. More importantly, we found a relationship between sleep characteristics and emotional recognition ability and a negative bias in emotional recognition in young males at risk for depression.

Holistic processing for bodies and body parts: New evidence from stereoscopic depth manipulations

Although holistic processing has been documented extensively for upright faces, it is unclear whether it occurs for other visual categories with more extensive substructure, such as body postures. Like faces, body postures have high social relevance, but they differ in having fine-grain organization not only of basic parts (e.g., arm) but also subparts (e.g., elbow, wrist, hand). To compare holistic processing for whole bodies and body parts, we employed a novel stereoscopic depth manipulation that creates either the percept of a whole body occluded by a set of bars, or of segments of a body floating in front of a background. Despite sharing low-level visual properties, only the stimulus perceived as being behind bars should be holistically "filled in" via amodal completion. In two experiments, we tested for better identification of individual body parts within the context of a body versus in isolation. Consistent with previous findings, recognition of body parts was better in the context of a whole body when the body was amodally completed behind occluders. However, when the same bodies were perceived as floating in strips, performance was significantly worse, and not significantly different, from that for amodally completed parts, supporting holistic processing of body postures. Intriguingly, performance was worst for parts in the frontal depth condition, suggesting that these effects may extend from gross body organization to a more local level. These results provide suggestive evidence that holistic representations may not be "all-or-none," but rather also operate on body regions of more limited spatial extent.

Developmental Commonalities between Object and Face Recognition in Adolescence

In the visual perception literature, the recognition of faces has often been contrasted with that of non-face objects, in terms of differences with regard to the role of parts, part relations and holistic processing. However, recent evidence from developmental studies has begun to blur this sharp distinction. We review evidence for a protracted development of object recognition that is reminiscent of the well-documented slow maturation observed for faces. The prolonged development manifests itself in a retarded processing of metric part relations as opposed to that of individual parts and offers surprising parallels to developmental accounts of face recognition, even though the interpretation of the data is less clear with regard to holistic processing. We conclude that such results might indicate functional commonalities between the mechanisms underlying the recognition of faces and non-face objects, which are modulated by different task requirements in the two stimulus domains.

Typical and Atypical Development of Functional Connectivity in the Face Network

Extensive studies have demonstrated that face recognition performance does not reach adult levels until adolescence. However, there is no consensus on whether such prolonged improvement stems from development of general cognitive factors or face-specific mechanisms. Here, we used behavioral experiments and functional magnetic resonance imaging (fMRI) to evaluate these two hypotheses. With a large cohort of children (n = 379), we found that the ability of face-specific recognition in humans increased with age throughout childhood and into late adolescence in both face memory and face perception. Neurally, to circumvent the potential problem of age differences in task performance, attention, or cognitive strategies in task-state fMRI studies, we measured the resting-state functional connectivity (RSFC) between the occipital face area (OFA) and fusiform face area (FFA) in human brain and found that the OFA-FFA RSFC increased until 11-13 years of age. Moreover, the OFA-FFA RSFC was selectively impaired in adults with developmental prosopagnosia (DP). In contrast, no age-related changes or differences between DP and normal adults were observed for RSFCs in the object system. Finally, the OFA-FFA RSFC matured earlier than face selectivity in either the OFA or FFA. These results suggest the critical role of the OFA-FFA RSFC in the development of face recognition. Together, our findings support the hypothesis that prolonged development of face recognition is face specific, not domain general.

Holistic Facial Composite Creation and Subsequent Video Line-up Eyewitness Identification Paradigm

The paradigm detailed in this manuscript describes an applied experimental method based on real police investigations during which an eyewitness or victim to a crime may create from memory a holistic facial composite of the culprit with the assistance of a police operator. The aim is that the composite is recognized by someone who believes that they know the culprit. For this paradigm, participants view a culprit actor on video and following a delay, participant-witnesses construct a holistic system facial composite. Controls do not construct a composite. From a series of arrays of computer-generated, but realistic faces, the holistic system construction method primarily requires participant-witnesses to select the facial images most closely meeting their memory of the culprit. Variation between faces in successive arrays is reduced until ideally the final image possesses a close likeness to the culprit. Participant-witness directed tools can also alter facial features, configurations between features and holistic properties (e.g., age, distinctiveness, skin tone), all within a whole face context. The procedure is designed to closely match the holistic manner by which humans' process faces. On completion, based on their memory of the culprit, ratings of composite-culprit similarity are collected from the participant-witnesses. Similar ratings are collected from culprit-acquaintance assessors, as a marker of composite recognition likelihood. Following a further delay, all participants--including the controls--attempt to identify the culprit in either a culprit-present or culprit-absent video line-up, to replicate circumstances in which the police have located the correct culprit, or an innocent suspect. Data of control and participant-witness line-up outcomes are presented, demonstrating the positive influence of holistic composite construction on identification accuracy. Correlational analyses are conducted to measure the relationship between assessor and participant-witness composite-culprit similarity ratings, delay, identification accuracy, and confidence to examine which factors influence video line-up outcomes.

Orienting Toward Face-Like Stimuli in Early Childhood

Newborn infants orient preferentially toward face-like or "protoface" stimuli and recent studies suggest similar reflexive orienting responses in adults. Little is known, however, about the operation of this mechanism in childhood. An attentional-cueing procedure was therefore developed to investigate protoface orienting in early childhood. Consistent with the extant literature, 5- to 6-year-old children (n = 25) exhibited orienting toward face-like stimuli; they responded faster when target location was cued by the appearance of a protoface stimulus than when location was cued by matched control patterns. The potential of this procedure to investigate the development of typical and atypical social perception is discussed.

Selectivity of Face Perception to Horizontal Information over Lifespan (from 6 to 74 Year Old)

Face recognition in young human adults preferentially relies on the processing of horizontally-oriented visual information. We addressed whether the horizontal tuning of face perception is modulated by the extensive experience humans acquire with faces over the lifespan, or whether it reflects an invariable processing bias for this visual category. We tested 296 subjects aged from 6 to 74 years in a face matching task. Stimuli were upright and inverted faces filtered to preserve information in the horizontal or vertical orientation, or both (HV) ranges. The reliance on face-specific processing was inferred based on the face inversion effect (FIE). FIE size increased linearly until young adulthood in the horizontal but not the vertical orientation range of face information. These findings indicate that the protracted specialization of the face processing system relies on the extensive experience humans acquire at encoding the horizontal information conveyed by upright faces.

Face perception and processing in early infancy: inborn predispositions and developmental changes

From birth it is critical for our survival to identify social agents and conspecifics. Among others stimuli, faces provide the required information. The present paper will review the mechanisms subserving face detection and face recognition, respectively, over development. In addition, the emergence of the functional and neural specialization for face processing as an experience-dependent process will be documented. Overall, the present work highlights the importance of both inborn predispositions and the exposure to certain experiences, shortly after birth, to drive the system to become functionally specialized to process faces in the first months of life.

A face detection bias for horizontal orientations develops in middle childhood

Faces are complex stimuli that can be described via intuitive facial features like the eyes, nose, and mouth, "configural" features like the distances between facial landmarks, and features that correspond to computations performed in the early visual system (e.g., oriented edges). With regard to this latter category of descriptors, adult face recognition relies disproportionately on information in specific spatial frequency and orientation bands: many recognition tasks are performed more accurately when adults have access to mid-range spatial frequencies (8-16 cycles/face) and horizontal orientations (Dakin and Watt, 2009). In the current study, we examined how this information bias develops in middle childhood. We recruited children between the ages of 5-10 years-old to participate in a simple categorization task that required them to label images according to whether they depicted a face or a house. Critically, children were presented with face and house images comprised either of primarily horizontal orientation energy, primarily vertical orientation energy, or both horizontal and vertical orientation energy. We predicted that any bias favoring horizontal information over vertical should be more evident in faces than in houses, and also that older children would be more likely to show such a bias than younger children. We designed our categorization task to be sufficiently easy that children would perform at near-ceiling accuracy levels, but with variation in response times that would reflect how they rely on different orientations as a function of age and object category. We found that horizontal bias for face detection (but not house detection) correlated significantly with age, suggesting an emergent category-specific bias for horizontal orientation energy that develops during middle childhood. These results thus suggest that the tuning of high-level recognition to specific low-level visual features takes place over several years of visual development.

Social presence and the composite face effect

A robust finding in social psychology research is that performance is modulated by the social nature of a given context, promoting social inhibition or facilitation effects. In the present experiment, we examined if and how social presence impacts holistic face perception processes by asking participants, in the presence of others and alone, to perform the composite face task. Results suggest that completing the task in the presence of others (i.e., mere co-action) is associated with better performance in face recognition (less bias and higher discrimination between presented and non-presented targets) and with a reduction in the composite face effect. These results make clear that social presence impact on the composite face effect does not occur because presence increases reliance on holistic processing as a "dominant" well-learned response, but instead, because it increases monitoring of the interference produced by automatic response.

Face recognition in schizophrenia disorder: A comprehensive review of behavioral, neuroimaging and neurophysiological studies

Facial emotion processing has been extensively studied in schizophrenia patients while general face processing has received less attention. The already published reviews do not address the current scientific literature in a complete manner. Therefore, here we tried to answer some questions that remain to be clarified, particularly: are the non-emotional aspects of facial processing in fact impaired in schizophrenia patients? At the behavioral level, our key conclusions are that visual perception deficit in schizophrenia patients: are not specific to faces; are most often present when the cognitive (e.g. attention) and perceptual demands of the tasks are important; and seems to worsen with the illness chronification. Although, currently evidence suggests impaired second order configural processing, more studies are necessary to determine whether or not holistic processing is impaired in schizophrenia patients. Neural and neurophysiological evidence suggests impaired earlier levels of visual processing, which might involve the deficits in interaction of the magnocellular and parvocellular pathways impacting on further processing. These deficits seem to be present even before the disorder out-set. Although evidence suggests that this deficit may be not specific to faces, further evidence on this question is necessary, in particularly more ecological studies including context and body processing.

Holistic Facial Composite Construction and Subsequent Lineup Identification Accuracy: Comparing Adults and Children

When the police have no suspect, they may ask an eyewitness to construct a facial composite of that suspect from memory. Faces are primarily processed holistically, and recently developed computerized holistic facial composite systems (e.g., EFIT-V) have been designed to match these processes. The reported research compared children aged 6-11 years with adults on their ability to construct a recognizable EFIT-V composite. Adult constructor's EFIT-Vs received significantly higher composite-suspect likeness ratings from assessors than children's, although there were some notable exceptions. In comparison to adults, the child constructors also overestimated the composite-suspect likeness of their own EFIT-Vs. In a second phase, there were no differences between adult controls and constructors in correct identification rates from video lineups. However, correct suspect identification rates by child constructors were lower than those of child controls, suggesting that a child's memory for the suspect can be adversely influenced by composite construction. Nevertheless, all child constructors coped with the demands of the EFIT-V system, and the implications for research, theory, and the criminal justice system practice are discussed.

Development of effective connectivity in the core network for face perception

This study measured effective connectivity within the core face network in young children using a paediatric magnetoencephalograph (MEG). Dynamic casual modeling (DCM) of brain responses was performed in a group of adults (N = 14) and a group of young children aged from 3 to 6 years (N = 15). Three candidate DCM models were tested, and the fits of the MEG data to the three models were compared at both individual and group levels. The results show that the connectivity structure of the core face network differs significantly between adults and children. Further, the relative strengths of face network connections were differentially modulated by experimental conditions in the two groups. These results support the interpretation that the core face network undergoes significant structural configuration and functional specialization between four years of age and adulthood.

Face processing in the brains of pre-school aged children measured with MEG

There are two competing theories concerning the development of face perception: a late maturation account and an early maturation account. Magnetoencephalography (MEG) neuroimaging holds promise for adjudicating between the two opposing accounts by providing objective neurophysiological measures of face processing, with sufficient temporal resolution to isolate face-specific brain responses from those associated with other sensory, cognitive and motor processes. The current study used a customized child MEG system to measure M100 and M170 brain responses in 15 children aged three to six years while they viewed faces, cars and their phase-scrambled counterparts. Compared to adults tested using the same stimuli in a conventional MEG system, children showed significantly larger and later M100 responses. Children's M170 responses, derived by subtracting the responses to phase-scrambled images from the corresponding images (faces or cars) were delayed in latency but otherwise resembled the adult M170. This component has not been obtained in previous studies of young children tested using conventional adult MEG systems. However children did show a markedly reduced M170 response to cars in comparison to adults. This may reflect children's lack of expertise with cars relative to faces. Taken together, these data are in accord with recent behavioural and neuroimaging data that support early maturation of the basic face processing functions.

Children (but not adults) judge similarity in own- and other-race faces by the color of their skin

Both face shape and pigmentation are diagnostic cues for face identification and categorization. In particular, both shape and pigmentation contribute to observers' categorization of faces by race. Although many theoretical accounts of the behavioral other-race effect either explicitly or implicitly depend on differential use of visual information as a function of category expertise, there is little evidence that observers do in fact differentially rely on distinct visual cues for own- and other-race faces. In the current study, we examined how Asian and Caucasian children (4-6 years of age) and adults use three-dimensional shape and two-dimensional pigmentation to make similarity judgments of White, Black, and Asian faces. Children in this age range are capable of making category judgments about race but also are sufficiently plastic with regard to the behavioral other-race effect that it seems as though their representations of facial appearance across different categories are still emerging. Using a simple match-to-sample similarity task, we found that children tend to use pigmentation to judge facial similarity more than adults and also that own-group versus other-group category membership appears to influence how quickly children learn to use shape information more readily. Therefore, we suggest that children continue to adjust how different visual information is weighted during early and middle childhood and that experience with faces affects the speed at which adult-like weightings are established.

Development of holistic vs. featural processing in face recognition

According to a classic view developed by Carey and Diamond (1977), young children process faces in a piecemeal fashion before adult-like holistic processing starts to emerge at the age of around 10 years. This is known as the encoding switch hypothesis. Since then, a growing body of studies have challenged the theory. This article will provide a critical appraisal of this literature, followed by an analysis of some more recent developments. We will conclude, quite contrary to the classical view, that holistic processing is not only present in early child development, but could even precede the development of part-based processing.