Importance of the inverted control in measuring holistic face processing with the composite effect and part-whole effect

The heterogeneity of holistic processing profiles in developmental prosopagnosia: holistic processing is impaired but not absent

Although it is generally assumed that face recognition relies on holistic processing, whether face recognition deficits observed in Developmental Prosopagnosics (DPs) can be explained by impaired holistic processing is currently under debate. The mixed findings from past studies could be the consequence of DP's heterogeneous deficit nature and the use of different measures of holistic processing-the inversion, part-whole, and composite tasks-which showed a poor association among each other. The present study aimed to gain further insight into the role of holistic processing in DPs. Groups of DPs and neurotypicals completed three tests measuring holistic face processing and non-face objects (i.e., Navon task). At a group level, DPs showed (1) diminished, but not absent, inversion and part-whole effects, (2) comparable magnitudes of the composite face effect and (3) global precedence effect in the Navon task. However, single-case analyses showed that these holistic processing deficits in DPs are heterogeneous.

Opposite size illusions for inverted faces and letters

Words are the primary means by which we communicate meaning and ideas, while faces provide important social cues. Studying visual illusions involving faces and words can elucidate the hierarchical processing of information as different regions of the brain are specialised for face recognition and word processing. A size illusion has previously been demonstrated for faces, whereby an inverted face is perceived as larger than the same stimulus upright. Here, two experiments replicate the face size illusion, and investigate whether the illusion is also present for individual letters (Experiment 1), and visual words and pseudowords (Experiment 2). Results confirm a robust size Illusion for faces. Letters, words and pseudowords and unfamiliar letters all show a reverse size illusion, as we previously demonstrated for human bodies. Overall, results indicate the illusion occurs in early perceptual stages upstream of semantic processing. Results are consistent with the idea of a general-purpose mechanism that encodes curvilinear shapes found in both scripts and our environment. Word and face perception rely on specialised, independent cognitive processes. The underestimation of the size of upright stimuli is specific to faces. Opposite size illusions may reflect differences in how size information is encoded and represented in stimulus-specialised neural networks, resulting in contrasting perceptual effects. Though words and faces differ visually, there is both symmetry and asymmetry in how the brain 'reads' them.

The role of inversion and face masks on simultaneous and delayed face matching tasks

Although it is generally accepted that face recognition relies on holistic processing, it has been suggested that the simultaneous face matching task may depend on a more analytical or featural processing approach. However, empirical evidence supporting this claim is limited. In two experiments, we further explored the role of holistic and featural processing on simultaneous face matching by manipulating holistic processing through inversion and presenting faces with or without face masks. The results from Experiment 1 revealed that both inversion and face masks impaired matching performance. However, while the inversion effect was evident in both full-view and masked faces, the mask effect was only found in upright, but not inverted, faces. These results were replicated in Experiment 2 but, the inversion and mask effects were stronger in delayed face matching than in simultaneous face matching. Our findings suggest that simultaneous face matching relies on holistic processing, but to a smaller extent compared to higher memory-demanding identification tasks.

Holistic and featural processing's link to face recognition varies by individual and task

While it is generally accepted that holistic processing facilitates face recognition, recent studies suggest that poor recognition might also arise from imprecise perception of local features in the face. This study aimed to examine to what extent holistic and featural processing relates to individual differences in face recognition ability (FRA), during face learning (Experiment 1) and face recognition (Experiment 2). Participants performed two tasks: (1) The "Cambridge Face Memory Test-Chinese" which measured participants' FRAs, and (2) an "old/new recognition memory test" encompassing whole faces (preserving holistic and featural processing) and faces revealed through a dynamic aperture (impairing holistic processing but preserving featural processing). Our results showed that participants recognised faces more accurately in conditions when holistic information was preserved, than when it is impaired. We also show that the better use of holistic processing during face learning and face recognition was associated with better FRAs. However, enhanced featural processing during recognition, but not during learning, was related to better FRAs. Together, our findings demonstrate that good face recognition depends on distinct roles played by holistic and featural processing at different stages of face recognition.

Emotions behind a mask: the value of disgust

The impact of face masks on social cognition and interaction became a popular topic due to the long-lasting COVID-19 pandemic. This theme persists in the focus of attention beyond the pandemic, since face covering not only reduces the overall amount of face information available but also introduces biases and prejudices affecting social perception at large. Many questions are still open. One of them is whether gender of beholders affects inferring of emotions covered by face masks. Reading covered faces may be particularly challenging for individuals with mental disorders, most of which are gender-specific. Previous findings are not only sparse, but inconclusive because most research had been conducted online with resulting samples heavily dominated by females. Here in a face-to-face study, females and males were presented with a randomized set of faces covered by masks. In a two-alternative forced-choice paradigm, participants had to indicate facial emotions displayed by posers. In general, the outcome dovetails with earlier findings that face masks affect emotion recognition in a dissimilar way: Inferring some emotions suffers more severely than others, with the most pronounced influence of mask wearing on disgust and close to ceiling recognition of fear and neutral expressions. Contrary to our expectations, however, males were on overall more proficient in emotion recognition. In particular, males substantially excelled in inferring disgust. The findings help to understand gender differences in recognition of disgust, the forgotten emotion of psychiatry, that is of substantial value for a wide range of mental disorders including schizophrenia. Watch Prof. Marina Pavlova discussing this her work and this article: https://vimeo.com/860126397/5966610f49?share=copy .

Facial expression and emotion

Human facial expressions are unique in their ability to express our emotions and communicate them to others. The mimic expression of basic emotions is very similar across different cultures and has also many features in common with other mammals. This suggests a common genetic origin of the association between facial expressions and emotion. However, recent studies also show cultural influences and differences. The recognition of emotions from facial expressions, as well as the process of expressing one's emotions facially, occurs within an extremely complex cerebral network. Due to the complexity of the cerebral processing system, there are a variety of neurological and psychiatric disorders that can significantly disrupt the coupling of facial expressions and emotions. Wearing masks also limits our ability to convey and recognize emotions through facial expressions. Through facial expressions, however, not only "real" emotions can be expressed, but also acted ones. Thus, facial expressions open up the possibility of faking socially desired expressions and also of consciously faking emotions. However, these pretenses are mostly imperfect and can be accompanied by short-term facial movements that indicate the emotions that are actually present (microexpressions). These microexpressions are of very short duration and often barely perceptible by humans, but they are the ideal application area for computer-aided analysis. This automatic identification of microexpressions has not only received scientific attention in recent years, but its use is also being tested in security-related areas. This article summarizes the current state of knowledge of facial expressions and emotions.

Communicating and reading emotion with masked faces in the Covid era: A short review of the literature

Face masks have proven to be key to slowing down the SARS-Cov2 virus spread in the COVID-19 pandemic context. However, wearing face masks is not devoid of "side-effects", at both the physical and psychosocial levels. In particular, masks hinder emotion reading from facial expressions as they hide a significant part of the face. This disturbs both holistic and featural processing of facial expressions and, therefore, impairs emotion recognition, and influences many aspects of human social behavior. Communication in general is disrupted by face masks, as they modify the wearer's voice and prevent the audience from using lip reading or other non-verbal cues for speech comprehension. Individuals suffering from psychiatric conditions with impairment of communication, are at higher risk of distress because masks increase their difficulties to read emotions from faces. The identification and acknowledgement of these "side-effects" on communication are necessary because they warrant further work on adaptive solutions that will help foster the use of face masks by the greatest number.

The Left-Side Bias Is Reduced to Other-Race Faces in Caucasian Individuals

One stable marker of face perception appears to be left-side bias, the tendency to rely more on information conveyed by the left side of the face than the right. Previous studies have shown that left-side bias is influenced by familiarity and prior experience with face stimuli. Since other-race facial recognition is characterized by reduced familiarity, in contrast to own-race facial recognition, the phenomenon of left-side bias is expected to be weaker for other-race faces. Among Chinese participants, face inversion has been found to eliminate the left-side bias associated with own-race faces. Therefore, it is of interest to know whether face inversion influences left-side bias for non-Chinese research participants and can be generalized across own- and other-race faces. This study assessed 65 Caucasian participants using upright and inverted chimeric Caucasian and Asian faces in an identity similarity-judgment task. Although a significant left-side bias was observed for upright own-race faces, this bias was eliminated by facial inversion, indicating that such a bias depends on the applicability of configural processing strategies. For other-race faces, there was no left-side bias in the upright condition. Interestingly, the inverted presentation yielded a right-side bias. These results show that while left-side bias is affected by familiarity differences between own- and other-race faces, it is a universal phenomenon for upright faces. Inverted presentation strongly reduces left-side bias and may even cause it to revert to right-side bias, suggesting that left-side bias depends on configural face processing.

Whole-object effects in visual word processing: Parallels with and differences from face recognition

Visual words and faces differ in their structural properties, but both are objects of high expertise. Holistic processing is said to characterize expert face recognition, but the extent to which whole-word processes contribute to word recognition is unclear, particularly as word recognition is thought to proceed by a component-based process. We review the evidence for experimental effects in word recognition that parallel those used to support holistic face processing, namely inversion effects, the part-whole task, and composite effects, as well as the status of whole-word processing in pure alexia and developmental dyslexia, contrasts between familiar and unfamiliar languages, and the differences between handwriting and typeset font. The observations support some parallels in whole-object influences between face and visual word recognition, but do not necessarily imply similar expert mechanisms. It remains to be determined whether and how the relative balance between part-based and whole-object processing differs for visual words and faces.

Different measures of holistic face processing tap into distinct but partially overlapping mechanisms

Holistic processing, which includes the integration of facial features and analysis of their relations to one another, is a hallmark of what makes faces 'special'. Various experimental paradigms purport to measure holistic processing but these have often produced inconsistent results. This has led researchers to question the nature and structure of the mechanism(s) underlying holistic processing. Using an individual differences approach, researchers have examined relations between various measures of holistic processing in an attempt to resolve these questions. In keeping with this, we examined relationships between four commonly used measures of holistic face processing in a large group of participants (N = 223): (1) The Face Inversion Effect, (2) the Part Whole Effect (PWE), (3) the Composite Face Effect, and (4) the Configural Featural Detection Task (CFDT). Several novel methodological and analytical elements were introduced, including the use of factor analysis and the inclusion of control conditions to confirm the face specificity of all of the effects measured. The four indexes of holistic processing derived from each measure loaded onto two factors, one encompassing the PWE and the CFDT, and one encompassing the CE. The 16 conditions tested across the four tasks loaded onto four factors, each factor corresponding to a different measure. These results, together with those of other studies, suggest that holistic processing is a multifaceted construct and that different measures tap into distinct but partially overlapping elements of it.

Chinese Aesthetic Mask: Three Forehead and Five Eyes-Holistic Processing and Facial Attractiveness

Human face processing has been attributed to holistic processing. Here, we ask whether humans are sensitive to configural information when perceiving facial attractiveness. By referring to a traditional Chinese aesthetic theory-Three Forehead and Five Eyes-we generated a series of faces that differed in spacing between facial features. We adopted a two-alternative forced-choice task in Experiment 1 and a rating task in Experiment 2 to assess attractiveness. Both tasks showed a consistent result: The faces which fit the Chinese aesthetic theory were chosen or rated as most attractive. This effect of configural information on facial attractiveness was larger for faces with highly attractive features than for faces with low attractive features. These findings provide experimental evidence for the traditional Chinese aesthetic theory. This issue can be further explored from the perspective of culture in the future.

The composite face effect is robust against perceptual misfit

The composite face effect—the failure of selective attention toward a target face half—is frequently used to study mechanisms of feature integration in faces. Here we studied how this effect depends on the perceptual fit between attended and unattended halves. We used composite faces that were rated by trained observers as either a seamless fit (i.e., close to a natural and homogeneous face) or as a deliberately bad quality of fit (i.e., unnatural, strongly segregated face halves). In addition, composites created by combining face halves randomly were tested. The composite face effect was measured as the alignment × congruency interaction (Gauthier and Bukach Cognition, 103, 322–330 2007), but also with alternative data analysis procedures (Rossion and Boremanse Journal of Vision, 8, 1–13 2008). We found strong but identical composite effects in all fit conditions. Fit quality neither increased the composite face effect nor was it attenuated by bad or random fit quality. The implications for a Gestalt account of holistic face processing are discussed.

The constancy of the holistic processing of unfamiliar faces: Evidence from the study-test consistency effect and the within-person motion and viewpoint invariance

It has been well documented that static face processing is holistic. Faces contain variant (e.g., motion, viewpoint) and invariant (race, sex) features. However, little research has focused on whether holistic face representations are tolerant of within-person variations. The present study thus investigated whether holistic face representations of faces are tolerant of within-person motion and viewpoint variations by manipulating study-test consistency using a complete composite paradigm. Participants were shown two faces sequentially and were asked to judge whether the faces' top halves were identical or different. The first face was a static face or a dynamic face rotated in depth at 30°, 60°, and 90°. The second face was either a different front-view static face (Experiment 1a, study-test inconsistent) or identical to the first face (Experiment 1b, study-test consistent). In Experiment 2, study-test consistency was manipulated within subjects, and inverted faces were included. Our results show that study-test consistency significantly enhanced the holistic processing of upright and inverted faces; this study-test consistency effect and holistic processing were not modulated by motion and viewpoint changes via depth rotation. Interestingly, we found holistic processing for moving study-test consistent inverted faces, but not for static inverted faces. What these results tell us about the nature of holistic face representation is discussed in depth with respect to earlier and current theories on face processing.

Sclera and Iris Color Interact to Influence Gaze Perception

The white sclera is important in facilitating gaze perception in humans. Iris color may likewise influence gaze perception but no previous studies have directly assessed its effect. We therefore examined how the interaction between sclera and iris color influences human gaze perception. We recorded the eye movements of human participants as they performed a visual search task with human faces exhibiting directed or averted gaze. The faces either exhibited light or dark irises. In addition, the faces had sclera that were depigmented (white) or pigmented (matched the color of the iris). We found that participants were quick and accurate in evaluating gaze regardless of iris color in faces with depigmented sclera. When the sclera were pigmented, participants were slower to evaluate the gaze of faces with both light and dark irises but these effects were most pronounced in the faces with dark irises. Furthermore, participants were generally less accurate in assessing faces with pigmented sclera when the irises were dark rather than light. Our results suggest that depigmented sclera are especially important for gaze perception in faces with dark irises. Because depigmented sclera likely evolved at a time when ancestral humans exhibited dark irises, the depigmented sclera may have been crucial for efficient and accurate gaze perception in ancestral humans.

Face pareidolia in the brain: Impact of gender and orientation

Research on face sensitivity is of particular relevance during the rapidly evolving Covid-19 pandemic leading to social isolation, but also calling for intact interaction and sharing. Humans possess high sensitivity even to a coarse face scheme, seeing faces in non-face images where real faces do not exist. The advantage of non-face images is that single components do not trigger face processing. Here by implementing a novel set of Face-n-Thing images, we examined (i) how face tuning alters with changing display orientation, and (ii) whether it is affected by observers’ gender. Young females and males were presented with a set of Face-n-Thing images either with canonical upright orientation or inverted 180° in the image plane. Face impression was substantially impeded by display inversion. Furthermore, whereas with upright display orientation, no gender differences were found, with inversion, Face-n-Thing images elicited face impression in females significantly more often. The outcome sheds light on the origins of the face inversion effect in general. Moreover, the findings open a way for examination of face sensitivity and underwriting brain networks in neuropsychiatric conditions related to the current pandemic (such as depression and anxiety), most of which are gender/sex-specific.

Spatially Filtered Emotional Faces Dominate during Binocular Rivalry

The present investigation explores the role of bottom-up and top-down factors in the recognition of emotional facial expressions during binocular rivalry. We manipulated spatial frequencies (SF) and emotive features and asked subjects to indicate whether the emotional or the neutral expression was dominant during binocular rivalry. Controlling the bottom-up saliency with a computational model, physically comparable happy and fearful faces were presented dichoptically with neutral faces. The results showed the dominance of emotional faces over neutral ones. In particular, happy faces were reported more frequently as the first dominant percept even in the presence of coarse information (at a low SF level: 2-6 cycle/degree). Following current theories of emotion processing, the results provide further support for the influence of positive compared to negative meaning on binocular rivalry and, for the first time, showed that individuals perceive the affective quality of happiness even in the absence of details in the visual display. Furthermore, our findings represent an advance in knowledge regarding the association between the high- and low-level mechanisms behind binocular rivalry.

The Time Course of Facial Expression Recognition Using Spatial Frequency Information: Comparing Pain and Core Emotions

We are able to recognize others' experience of pain from their facial expressions. However, little is known about what makes the recognition of pain possible and whether it is similar or different from core emotions. This study investigated the mechanisms underpinning the recognition of pain expressions, in terms of spatial frequency (SF) information analysis, and compared pain with 2 core emotions (ie, fear and happiness). Two experiments using a backward masking paradigm were conducted to examine the time course of low- and high-SF information processing, by manipulating the presentation duration of face stimuli and target-mask onset asynchrony. Overall, we found a temporal advantage of low-SF over high-SF information for expression recognition, including pain. This asynchrony between low- and high-SF happened at a very early stage of information extraction, which indicates that the decoding of low-SF expression information is not only faster but possibly occurs before the processing of high-SF information. Interestingly, the recognition of pain was also found to be slower and more difficult than core emotions. It is suggested that more complex decoding process may be involved in the successful recognition of pain from facial expressions, possibly due to the multidimensional nature of pain experiences. PERSPECTIVE: Two studies explore the perceptual and temporal properties of the decoding of pain facial expressions. At very early stages of attention, the recognition of pain was found to be more difficult than fear and happiness. It suggests that pain is a complex expression, and requires additional time to detect and process.

Rule-based or information-integration category: processing of the self-face

This study investigated the differences between categorizing the self-face and other faces. Additionally, the study aimed to determine whether self-face categorization is consistent with dual-system categorization, such as in the competition between verbal and implicit systems (COVIS) model, or whether the self-face uses different categorizing methods than those used with other faces. The experiment adopted a dual-task paradigm to examine how participants complete rule-based/information-integration categorization tasks of the self-face/other faces and their method of processing when a numerical Stroop task was introduced. Results indicated that participants processed the self-face better than other faces in rule-based categorization, and there was no significant difference between categorization of the self-face and other faces during a single or dual task. This suggests there is a self-processing advantage in classification tasks; however, categorization based on face stimuli is not consistent with the COVIS model. Face categorization has a self-advantage effect, and categorization of human faces is distinctive from other types of categorization.

Investigating the Time Course of Part-Based and Holistic Processing in Face Perception

Human has an exceptional ability for face recognition to keep up social network. However, it is unclear to understand the mechanisms of face recognition until now. Specifically, there is less research to examine the time course of part-based and holistic processing when these two routes trigger and finish. In the present experiments, the exposure time was manipulated to examine the time course of face processing and found evidence suggesting that holistic processing occurs shortly after part-based processing at about 200 ms, and can last for a relatively long duration up to 2,000 ms. These results may support to a dual-route model comprising holistic processing and part-based processing in face perception. Moreover, our findings were inconsistent with the previous study which suggests that no holistic processing was observed at the relatively long duration, and suspected that perceptual discriminability may have been responsible for the discrepancy.

Use-inspired basic research on individual differences in face identification: implications for criminal investigation and security

This journal is dedicated to "use-inspired basic research" where a problem in the world shapes the hypotheses for study in the laboratory. This review considers the role of individual variation in face identification and the challenges and opportunities this presents in security and criminal investigations. We show how theoretical work conducted on individual variation in face identification has, in part, been stimulated by situations presented in the real world. In turn, we review the contribution of theoretical work on individual variation in face processing and how this may help shape the practical identification of faces in applied situations. We consider two cases in detail. The first case is that of security officers; gatekeepers who use facial ID to grant entry or deny access. One applied example, where much research has been conducted, is passport control officers who are asked to match a person in front of them to a photograph shown on their ID. What happens if they are poor at making such face matching decisions and can they be trained to improve their performance? Second, we outline the case of "super-recognisers", people who are excellent at face recognition. Here it is interesting to consider whether these individuals can be strategically allocated to security and criminal roles, to maximise the identification of suspects. We conclude that individual differences are one of the largest documented sources of error in face matching and face recognition but more work is needed to account for these differences within theoretical models of face processing.

Inversion Impairs Expert Budgerigar Identity Recognition: A Face-Like Effect for a Nonface Object of Expertise

The face-inversion effect is the finding that picture-plane inversion disproportionately impairs face recognition compared to object recognition and is now attributed to greater orientation-sensitivity of holistic processing for faces but not common objects. Yet, expert dog judges have showed similar recognition deficits for inverted dogs and inverted faces, suggesting that holistic processing is not specific to faces but to the expert recognition of perceptually similar objects. Although processing changes in expert object recognition have since been extensively documented, no other studies have observed the distinct recognition deficits for inverted objects-of-expertise that people as face experts show for faces. However, few studies have examined experts who recognize individual objects similar to how people recognize individual faces. Here we tested experts who recognize individual budgerigar birds. The effect of inversion on viewpoint-invariant budgerigar and face recognition was compared for experts and novices. Consistent with the face-inversion effect, novices showed recognition deficits for inverted faces but not for inverted budgerigars. By contrast, experts showed equal recognition deficits for inverted faces and budgerigars. The results are consistent with the hypothesis that processes underlying the face-inversion effect are specific to the expert individuation of perceptually similar objects.

Does a Flatter General Gradient of Visual Attention Explain Peripheral Advantages and Central Deficits in Deaf Adults?

Individuals deaf from early age often outperform hearing individuals in the visual periphery on attention-dependent dorsal stream tasks (e.g., spatial localization or movement detection), but sometimes show central visual attention deficits, usually on ventral stream object identification tasks. It has been proposed that early deafness adaptively redirects attentional resources from central to peripheral vision to monitor extrapersonal space in the absence of auditory cues, producing a more evenly distributed attention gradient across visual space. However, little direct evidence exists that peripheral advantages are functionally tied to central deficits, rather than determined by independent mechanisms, and previous studies using several attention tasks typically report peripheral advantages or central deficits, not both. To test the general altered attentional gradient proposal, we employed a novel divided attention paradigm that measured target localization performance along a gradient from parafoveal to peripheral locations, independent of concurrent central object identification performance in prelingually deaf and hearing groups who differed in access to auditory input. Deaf participants without cochlear implants (No-CI), with cochlear implants (CI), and hearing participants identified vehicles presented centrally, and concurrently reported the location of parafoveal (1.4°) and peripheral (13.3°) targets among distractors. No-CI participants but not CI participants showed a central identification accuracy deficit. However, all groups displayed equivalent target localization accuracy at peripheral and parafoveal locations and nearly parallel parafoveal-peripheral gradients. Furthermore, the No-CI group's central identification deficit remained after statistically controlling peripheral performance; conversely, the parafoveal and peripheral group performance equivalencies remained after controlling central identification accuracy. These results suggest that, in the absence of auditory input, reduced central attentional capacity is not necessarily associated with enhanced peripheral attentional capacity or with flattening of a general attention gradient. Our findings converge with earlier studies suggesting that a general graded trade-off of attentional resources across the visual field does not adequately explain the complex task-dependent spatial distribution of deaf-hearing performance differences reported in the literature. Rather, growing evidence suggests that the spatial distribution of attention-mediated performance in deaf people is determined by sophisticated cross-modal plasticity mechanisms that recruit specific sensory and polymodal cortex to achieve specific compensatory processing goals.

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.

Modulation of the composite face effect by unintended emotion cues

When upper and lower regions from different emotionless faces are aligned to form a facial composite, observers 'fuse' the two halves together, perceptually. The illusory distortion induced by task-irrelevant ('distractor') halves hinders participants' judgements about task-relevant ('target') halves. This composite-face effect reveals a tendency to integrate feature information from disparate regions of intact upright faces, consistent with theories of holistic face processing. However, observers frequently perceive emotion in ostensibly neutral faces, contrary to the intentions of experimenters. This study sought to determine whether this 'perceived emotion' influences the composite-face effect. In our first experiment, we confirmed that the composite effect grows stronger as the strength of distractor emotion increased. Critically, effects of distractor emotion were induced by weak emotion intensities, and were incidental insofar as emotion cues hindered image matching, not emotion labelling per se. In Experiment 2, we found a correlation between the presence of perceived emotion in a set of ostensibly neutral distractor regions sourced from commonly used face databases, and the strength of illusory distortion they induced. In Experiment 3, participants completed a sequential matching composite task in which half of the distractor regions were rated high and low for perceived emotion, respectively. Significantly stronger composite effects were induced by the high-emotion distractor halves. These convergent results suggest that perceived emotion increases the strength of the composite-face effect induced by supposedly emotionless faces. These findings have important implications for the study of holistic face processing in typical and atypical populations.

The impact of orientation filtering on face-selective neurons in monkey inferior temporal cortex

Faces convey complex social signals to primates. These signals are tolerant of some image transformations (e.g. changes in size) but not others (e.g. picture-plane rotation). By filtering face stimuli for orientation content, studies of human behavior and brain responses have shown that face processing is tuned to selective orientation ranges. In the present study, for the first time, we recorded the responses of face-selective neurons in monkey inferior temporal (IT) cortex to intact and scrambled faces that were filtered to selectively preserve horizontal or vertical information. Guided by functional maps, we recorded neurons in the lateral middle patch (ML), the lateral anterior patch (AL), and an additional region located outside of the functionally defined face-patches (CONTROL). We found that neurons in ML preferred horizontal-passed faces over their vertical-passed counterparts. Neurons in AL, however, had a preference for vertical-passed faces, while neurons in CONTROL had no systematic preference. Importantly, orientation filtering did not modulate the firing rate of neurons to phase-scrambled face stimuli in any recording region. Together these results suggest that face-selective neurons found in the face-selective patches are differentially tuned to orientation content, with horizontal tuning in area ML and vertical tuning in area AL.

Face Perception and Test Reliabilities in Congenital Prosopagnosia in Seven Tests

Congenital prosopagnosia, the innate impairment in recognizing faces, is a very heterogeneous disorder with different phenotypical manifestations. To investigate the nature of prosopagnosia in more detail, we tested 16 prosopagnosics and 21 controls with an extended test battery addressing various aspects of face recognition. Our results show that prosopagnosics exhibited significant impairments in several face recognition tasks: impaired holistic processing (they were tested amongst others with the Cambridge Face Memory Test (CFMT)) as well as reduced processing of configural information of faces. This test battery also revealed some new findings. While controls recognized moving faces better than static faces, prosopagnosics did not exhibit this effect. Furthermore, prosopagnosics had significantly impaired gender recognition—which is shown on a groupwise level for the first time in our study. There was no difference between groups in the automatic extraction of face identity information or in object recognition as tested with the Cambridge Car Memory Test. In addition, a methodological analysis of the tests revealed reduced reliability for holistic face processing tests in prosopagnosics. To our knowledge, this is the first study to show that prosopagnosics showed a significantly reduced reliability coefficient (Cronbach’s alpha) in the CFMT compared to the controls. We suggest that compensatory strategies employed by the prosopagnosics might be the cause for the vast variety of response patterns revealed by the reduced test reliability. This finding raises the question whether classical face tests measure the same perceptual processes in controls and prosopagnosics.

On the particular vulnerability of face recognition to aging: a review of three hypotheses

Age-related face recognition deficits are characterized by high false alarms to unfamiliar faces, are not as pronounced for other complex stimuli, and are only partially related to general age-related impairments in cognition. This paper reviews some of the underlying processes likely to be implicated in theses deficits by focusing on areas where contradictions abound as a means to highlight avenues for future research. Research pertaining to the three following hypotheses is presented: (i) perceptual deterioration, (ii) encoding of configural information, and (iii) difficulties in recollecting contextual information. The evidence surveyed provides support for the idea that all three factors are likely to contribute, under certain conditions, to the deficits in face recognition seen in older adults. We discuss how these different factors might interact in the context of a generic framework of the different stages implicated in face recognition. Several suggestions for future investigations are outlined.

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.

Brain-decoding fMRI reveals how wholes relate to the sum of parts

The human brain performs many nonlinear operations in order to extract relevant information from local inputs. How can we observe and quantify these effects within and across large patches of cortex? In this paper, we discuss the application of multi-voxel pattern analysis (MVPA) in functional magnetic resonance imaging (fMRI) to address this issue. Specifically, we show how MVPA (i) allows to compare various possibilities of part combinations into wholes, such as taking the mean, weighted mean, or the maximum of responses to the parts; (ii) can be used to quantify the parameters of these combinations; and (iii) can be applied in various experimental paradigms. Through these procedures, fMRI helps to obtain a computational understanding of how local information is integrated into larger wholes in various cortical regions.

Global Shape Information Increases but Color Information Decreases the Composite Face Effect

The separation of visual shape and surface information may be useful for understanding holistic face perception—that is, the perception of a face as a single unit (Jiang, Blanz, & Rossion, 2011, Visual Cognition, 19, 1003–1034). A widely used measure of holistic face perception is the composite face effect (CFE), in which identical top face halves appear different when aligned with bottom face halves from different identities. In the present study the influences of global face shape (ie contour of the face) and color information on the CFE are investigated, with the hypothesis that global face shape supports but color impairs holistic face perception as measured in this paradigm. In experiment 1 the CFE is significantly increased when face stimuli possess natural global shape information than when cropped to a generic (ie oval) global shape; this effect is not found when the stimuli are presented inverted. In experiment 2 the CFE is significantly decreased when face stimuli are presented with color information than when presented in grayscale. These findings indicate that grayscale stimuli maintaining natural global face shape information provide the most adept measure of holistic face perception in the behavioral composite face paradigm. More generally, they show that reducing different types of information diagnostic for individual face perception can have opposite effects on the CFE, illustrating the functional dissociation between shape and surface information in face perception.

The effects of information type (features vs. configuration) and location (eyes vs. mouth) on the development of face perception

The goal of the current study was to investigate the development of face processing strategies in a perceptual discrimination task. Children (7-12 years of age) and young adults were administered the Face Dimensions Task. In the Face Dimensions Task, participants were asked to judge whether two simultaneously presented faces were the "same" or "different". For the "same" trials, the two faces were identical. For the "different" trials, the faces differed in either the spacing between the eyes, the spacing between the nose and the mouth, the size of the eyes, or the size of the mouth. The main finding was that 7- to 10-year-old children showed no difference in their ability to discriminate differences in eye size and eye spacing but showed a poor ability to discriminate differences in nose and mouth spacing and, to a lesser extent, mouth size. The developmental lag between nose-mouth discriminations and the other featural and configural discriminations was reduced in older children and eliminated by young adulthood. These results indicate that the type of face information (i.e., configural vs. featural) and its location (i.e., eye vs. mouth) jointly contribute to the development of face perception abilities.

On the facilitative effects of face motion on face recognition and its development

For the past century, researchers have extensively studied human face processing and its development. These studies have advanced our understanding of not only face processing, but also visual processing in general. However, most of what we know about face processing was investigated using static face images as stimuli. Therefore, an important question arises: to what extent does our understanding of static face processing generalize to face processing in real-life contexts in which faces are mostly moving? The present article addresses this question by examining recent studies on moving face processing to uncover the influence of facial movements on face processing and its development. First, we describe evidence on the facilitative effects of facial movements on face recognition and two related theoretical hypotheses: the supplementary information hypothesis and the representation enhancement hypothesis. We then highlight several recent studies suggesting that facial movements optimize face processing by activating specific face processing strategies that accommodate to task requirements. Lastly, we review the influence of facial movements on the development of face processing in the first year of life. We focus on infants' sensitivity to facial movements and explore the facilitative effects of facial movements on infants' face recognition performance. We conclude by outlining several future directions to investigate moving face processing and emphasize the importance of including dynamic aspects of facial information to further understand face processing in real-life contexts.

When recognition memory is independent of hippocampal function

Hippocampal damage has been thought to result in broad memory impairment. Recent studies in humans, however, have raised the possibility that recognition memory for faces might be spared. In five experiments we investigated face recognition in patients with hippocampal lesions (H) or large medial temporal lobe (MTL) lesions, including patients where neurohistological information was available. Recognition of novel faces was unequivocally intact in H patients but only at a short retention interval. Recognition memory for words, buildings, inverted faces, and famous faces was impaired. For MTL patients, recognition memory was impaired for all materials and across all retention intervals. These results indicate that structures other than the hippocampus, perhaps the perirhinal cortex, can support face recognition memory in H patients under some conditions. The fact that the faces were novel when recognition memory was intact does not fully account for our findings. We propose that the role of the hippocampus in recognition memory is related to how recognition decisions are accomplished. In typical recognition tasks, participants proceed by forming an association between a study item and the study list, and the recognition decision is later made based on whether participants believe the item was on the study list. We suggest that face recognition is an exception to this principle and that, at short retention intervals, participants can make their recognition decisions without making explicit reference to the study list. Important features of faces that might make face recognition exceptional are that they are processed holistically and are difficult to verbally label.

Implications of holistic face processing in autism and schizophrenia

People with autism and schizophrenia have been shown to have a local bias in sensory processing and face recognition difficulties. A global or holistic processing strategy is known to be important when recognizing faces. Studies investigating face recognition in these populations are reviewed and show that holistic processing is employed despite lower overall performance in the tasks used. This implies that holistic processing is necessary but not sufficient for optimal face recognition and new avenues for research into face recognition based on network models of autism and schizophrenia are proposed.