Do children with autism perceive second-order relational features? The case of the Thatcher illusion

Sizing up the crowd: Assessing spatial integration difficulties in body size judgements across eating disorder symptomatology

Introduction

Body size judgements are frequently biased, or inaccurate, and these errors are further exaggerated for individuals with eating disorders. Within the eating disorder literature, it has been suggested that exaggerated errors in body size judgements are due to difficulties with integration. Across two experiments, we developed a novel integration task, named the Ebbinghaus Illusion for Bodies in Virtual Reality (VR), to assess whether nearby bodies influence the perceived size of a single body. VR was used to simulate the appearance of a small crowd around a central target body.

Method and Results

In Experiment 1 (N = 412), participants were required to judge the size of a central female target within a crowd. Experiment 1 revealed an Ebbinghaus Illusion, in which a central female appeared larger when surrounded by small distractors, but comparatively smaller when surrounded by large distractors. In other words, the findings of Experiment 1 demonstrate that surrounding crowd information is integrated when judging an individual's body size; a novel measure of spatial integration (i.e., an Ebbinghaus Illusion for Bodies in VR). In Experiment 2 (N = 96), female participants were selected based on high (n = 43) and low (n = 53) eating disorder symptomatology. We examined whether the magnitude of this illusion would differ amongst those with elevated versus low eating disorder symptomatology, in accordance with weak central coherence theory, with the high symptomatology group displaying less spatial integration relative to the low group. The results of Experiment 2 similarly found an Ebbinghaus Illusion for Bodies in VR. However, illusion magnitude did not vary across high and low symptomatology groups.

Discussion

Overall, these findings demonstrate that surrounding crowd information is integrated when judging individual body size; however, those with elevated eating disorder symptomatology did not show any integration deficit on this broader measure of spatial integration.

Configural properties of face portraits change between childhood and adulthood

Adult observers are sensitive to the configuration of facial features within a face, able to distinguish between relative differences in feature spacing, and detecting deviations from typical facial appearance. How does the representation of the typical configuration of facial features develop? While there is a great deal of work describing children’s developing abilities to detect differences in feature spacing across face images, there is substantially less work examining what children think constitutes a typical arrangement of facial features. In the current study, we investigated this issue using a production task in which adults and 5- to 10-year-old children created a face “portrait” by arranging the eyes, nose, and mouth of a standard face within an empty outline. Using this simple task, we found differences in face configuration across age groups, such that children of all ages made far larger errors than adult participants, expanding facial features outward from the center of the face more than adults. These results were not affected by face inversion, potentially implying a domain-general rather than face-specific process. We also found that children of all ages endorsed the correct configuration as a best likeness in a perceptual task. We discuss these results in terms of ongoing debate regarding the extent to which configural processing is a meaningful component of face recognition and the conclusions we can draw from production paradigms as compared to purely perceptual tasks.

Atypically slow processing of faces and non-faces in older autistic adults

Face recognition is a fundamental function that requires holistic processing. Differences in face processing have been consistently identified in autistic children, but it is unknown whether these differences persist across the adult lifespan. Using event-related functional magnetic resonance imaging, we measured holistic face processing with a rapid Mooney faces task in 50 autistic and 49 non-autistic participants (30–74 years). Behavioral tasks included a self-paced version of the same paradigm and a global–local processing task (Navon). Reduced detection rates for faces, but not non-faces, were found in autistic adults, including slower responses on all conditions. Without time constraints, differences in accuracy disappeared between groups, although reaction times in correctly identifying faces remained higher in autistic adults. The functional magnetic resonance imaging results showed lower activation in the left and right superior frontal gyrus in the autism group but no age-related differences. Overall, our findings point toward slower information processing speed rather than a face recognition deficit in autistic adults. This suggests that face-processing differences are not a core feature of autism across the adult lifespan.

Weaker McGurk Effect for Rubin's Vase-Type Speech in People With High Autistic Traits

While visual information from facial speech modulates auditory speech perception, it is less influential on audiovisual speech perception among autistic individuals than among typically developed individuals. In this study, we investigated the relationship between autistic traits (Autism-Spectrum Quotient; AQ) and the influence of visual speech on the recognition of Rubin's vase-type speech stimuli with degraded facial speech information. Participants were 31 university students (13 males and 18 females; mean age: 19.2, SD: 1.13 years) who reported normal (or corrected-to-normal) hearing and vision. All participants completed three speech recognition tasks (visual, auditory, and audiovisual stimuli) and the AQ-Japanese version. The results showed that accuracies of speech recognition for visual (i.e., lip-reading) and auditory stimuli were not significantly related to participants' AQ. In contrast, audiovisual speech perception was less susceptible to facial speech perception among individuals with high rather than low autistic traits. The weaker influence of visual information on audiovisual speech perception in autism spectrum disorder (ASD) was robust regardless of the clarity of the visual information, suggesting a difficulty in the process of audiovisual integration rather than in the visual processing of facial speech.

The Shepard Illusion Is Reduced in Children With an Autism Spectrum Disorder Because of Perceptual Rather Than Attentional Mechanisms

Earlier studies demonstrate reduced illusion strength in the Shepard illusion in adults and adolescents with an autism spectrum disorder (ASD) and in typically developing (TD) adults with high levels of autistic traits. We measured the strength of the Shepard illusion in ASD and TD children and tested if ten different eye-tracking measurements could predict group differences in illusion strength. The ASD children demonstrated reduced illusion strength relative to the TD group. Despite this, there were no mean differences on any of the eye-tracking measurements between groups. Even though none of the eye-tracking measurements revealed mean differences between the two groups, the degree to which spatial attention was directed toward the standard stimulus, as indexed by the number of saccades within and toward this stimulus, predicted the strength of the illusion in the overall sample. Furthermore, this active scanning of the standard stimulus was found to enhance illusion strength more strongly in the ASD than the TD group. Together, we conclude that scan patterns and the degree to which participants are able to shift between different locations in a visual scene did not account for group differences in illusion strength. Thus, the reduced strength of the Shepard illusion in ASD does not appear to be driven by how attention shifts or is spatially allocated. Rather, differences may relate instead to perceptual mechanisms that integrate visual information. Strategies that may aid ASD individuals to see this illusion more strongly could have them make even more eye movements within and between the stimuli presented in the illusion display.

Individual differences and the effect of face configuration information in the McGurk effect

The McGurk effect, which denotes the influence of visual information on audiovisual speech perception, is less frequently observed in individuals with autism spectrum disorder (ASD) compared to those without it; the reason for this remains unclear. Several studies have suggested that facial configuration context might play a role in this difference. More specifically, people with ASD show a local processing bias for faces-that is, they process global face information to a lesser extent. This study examined the role of facial configuration context in the McGurk effect in 46 healthy students. Adopting an analogue approach using the Autism-Spectrum Quotient (AQ), we sought to determine whether this facial configuration context is crucial to previously observed reductions in the McGurk effect in people with ASD. Lip-reading and audiovisual syllable identification tasks were assessed via presentation of upright normal, inverted normal, upright Thatcher-type, and inverted Thatcher-type faces. When the Thatcher-type face was presented, perceivers were found to be sensitive to the misoriented facial characteristics, causing them to perceive a weaker McGurk effect than when the normal face was presented (this is known as the McThatcher effect). Additionally, the McGurk effect was weaker in individuals with high AQ scores than in those with low AQ scores in the incongruent audiovisual condition, regardless of their ability to read lips or process facial configuration contexts. Our findings, therefore, do not support the assumption that individuals with ASD show a weaker McGurk effect due to a difficulty in processing facial configuration context.

Social cognition in autism: Face tuning

Faces convey valuable information for social cognition, effective interpersonal interaction, and non-verbal communication. Face perception is believed to be atypical in autism, but the origin of this deficit is controversial. Dominant featural face encoding is suggested to be responsible for face tuning scarcity. Here we used a recently developed Face-n-Food paradigm for studying face tuning in individuals with autistic spectrum disorders (ASD). The key benefit of these images is that single components do not explicitly trigger face processing. In a spontaneous recognition task, adolescents with autism and typically developing matched controls were presented with a set of Face-n-Food images in different degree resembling a face (slightly bordering on the Giuseppe Arcimboldo style). The set of images was shown in a predetermined order from the least to most resembling a face. Thresholds for recognition of the Face-n-Food images as a face in ASD individuals were substantially higher than in typically developing controls: they did not report seeing a face on the images, which controls easily recognized as a face, and gave overall fewer face responses. This outcome not only lends support to atypical face tuning, but provides novel insights into the origin of face encoding deficits in autism.

Atypical perception in autism: A failure of perceptual specialization?

We examined whether reduced perceptual specialization underlies atypical perception in autism spectrum disorder (ASD) testing classifications of stimuli that differ either along integral dimensions (prototypical integral dimensions of value and chroma), or along separable dimensions (prototypical separable dimensions of value and size). Current models of the perception of individuals with an ASD would suggest that on these tasks, individuals with ASD would be as, or more, likely to process dimensions as separable, regardless of whether they represented separable or integrated dimensions. In contrast, reduced specialization would propose that individuals with ASD would respond in a more integral manner to stimuli that differ along separable dimensions, and at the same time, respond in a more separable manner to stimuli that differ along integral dimensions. A group of nineteen adults diagnosed with high functioning ASD and seventeen typically developing participants of similar age and IQ, were tested on speeded and restricted classifications tasks. Consistent with the reduced specialization account, results show that individuals with ASD do not always respond more analytically than typically developed (TD) observers: Dimensions identified as integral for TD individuals evoke less integral responding in individuals with ASD, while those identified as separable evoke less analytic responding. These results suggest that perceptual representations are more broadly tuned and more flexibly represented in ASD. Autism Res 2017, 10: 1510-1522. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

Visual Illusions: An Interesting Tool to Investigate Developmental Dyslexia and Autism Spectrum Disorder

A visual illusion refers to a percept that is different in some aspect from the physical stimulus. Illusions are a powerful non-invasive tool for understanding the neurobiology of vision, telling us, indirectly, how the brain processes visual stimuli. There are some neurodevelopmental disorders characterized by visual deficits. Surprisingly, just a few studies investigated illusory perception in clinical populations. Our aim is to review the literature supporting a possible role for visual illusions in helping us understand the visual deficits in developmental dyslexia and autism spectrum disorder. Future studies could develop new tools - based on visual illusions - to identify an early risk for neurodevelopmental disorders.

Intact perception but abnormal orientation towards face-like objects in young children with ASD

There is ample behavioral evidence of diminished orientation towards faces as well as the presence of face perception impairments in autism spectrum disorder (ASD), but the underlying mechanisms of these deficits are still unclear. We used face-like object stimuli that have been shown to evoke pareidolia in typically developing (TD) individuals to test the effect of a global face-like configuration on orientation and perceptual processes in young children with ASD and age-matched TD controls. We show that TD children were more likely to look first towards upright face-like objects than children with ASD, showing that a global face-like configuration elicit a stronger orientation bias in TD children as compared to children with ASD. However, once they were looking at the stimuli, both groups spent more time exploring the upright face-like object, suggesting that they both perceived it as a face. Our results are in agreement with abnormal social orienting in ASD, possibly due to an abnormal tuning of the subcortical pathway, leading to poor orienting and attention towards faces. Our results also indicate that young children with ASD can perceive a generic face holistically, such as face-like objects, further demonstrating holistic processing of faces in ASD.

Neural responses to emotional expression information in high- and low-spatial frequency in autism: evidence for a cortical dysfunction

Despite an overall consensus that Autism Spectrum Disorder (ASD) entails atypical processing of human faces and emotional expressions, the role of neural structures involved in early facial processing remains unresolved. An influential model for the neurotypical brain suggests that face processing in the fusiform gyrus and the amygdala is based on both high-spatial frequency (HSF) information carried by a parvocellular pathway, and low-spatial frequency (LSF) information separately conveyed by a magnocellular pathway. Here, we tested the fusiform gyrus and amygdala sensitivity to emotional face information conveyed by these distinct pathways in ASD individuals (and matched Controls). During functional Magnetical Resonance Imaging (fMRI), participants reported the apparent gender of hybrid face stimuli, made by merging two different faces (one in LSF and the other in HSF), out of which one displayed an emotional expression (fearful or happy) and the other was neutral. Controls exhibited increased fusiform activity to hybrid faces with an emotional expression (relative to hybrids composed only with neutral faces), regardless of whether this was conveyed by LSFs or HSFs in hybrid stimuli. ASD individuals showed intact fusiform response to LSF, but not HSF, expressions. Furthermore, the amygdala (and the ventral occipital cortex) was more sensitive to HSF than LSF expressions in Controls, but exhibited an opposite preference in ASD. Our data suggest spared LSF face processing in ASD, while cortical analysis of HSF expression cues appears affected. These findings converge with recent accounts suggesting that ASD might be characterized by a difficulty in integrating multiple local information and cause global processing troubles unexplained by losses in low spatial frequency inputs.

Holistic processing of faces as measured by the Thatcher illusion is intact in autism spectrum disorders

Impaired face perception in autism spectrum disorders is thought to reflect a perceptual style characterized by componential rather than configural processing of faces. This study investigated face processing in adolescents with autism spectrum disorders using the Thatcher illusion, a perceptual phenomenon exhibiting 'inversion effects' that characterize typical face processing. While previous studies used a limited range of face orientations, we measured perception of normality/grotesqueness of faces at seven orientations ranging from upright to inverted to allow for a detailed comparison of both reaction time and error by orientation profiles. We found that, like their typically developing peers, adolescents with autism spectrum disorders show strong inversion effects whereby reaction times were longer and error rates greater at inverted when compared to upright orientations. Additionally, the adolescents with autism spectrum disorders, like their peers in the typically developing group, show a marked nonlinearity in the error by orientation profile. Error is roughly constant out to 90° and then increases steeply, indicating a sudden shift from configural to local processing that reflects experience with faces in their typical orientations. These findings agree with recent reports that face perception is qualitatively similar in autistic and neurotypical groups.

Thatcher's Britain: A New Take on an Old Illusion

The Thatcher Illusion is generally discussed as a phenomenon related to face perception. Nonetheless, we show that compellingly strong Thatcher Effects can be elicited with nonface stimuli, provided that the stimulus set has a familiar standard configuration and a canonical view. Apparently, the Thatcher Illusion is not about faces, and nor is it about Thatcher. It just might, however, be about Britain.

Subjective experience of episodic memory and metacognition: a neurodevelopmental approach

Episodic retrieval is characterized by the subjective experience of remembering. This experience enables the co-ordination of memory retrieval processes and can be acted on metacognitively. In successful retrieval, the feeling of remembering may be accompanied by recall of important contextual information. On the other hand, when people fail (or struggle) to retrieve information, other feelings, thoughts, and information may come to mind. In this review, we examine the subjective and metacognitive basis of episodic memory function from a neurodevelopmental perspective, looking at recollection paradigms (such as source memory, and the report of recollective experience) and metacognitive paradigms such as the feeling of knowing). We start by considering healthy development, and provide a brief review of the development of episodic memory, with a particular focus on the ability of children to report first-person experiences of remembering. We then consider neurodevelopmental disorders (NDDs) such as amnesia acquired in infancy, autism, Williams syndrome, Down syndrome, or 22q11.2 deletion syndrome. This review shows that different episodic processes develop at different rates, and that across a broad set of different NDDs there are various types of episodic memory impairment, each with possibly a different character. This literature is in agreement with the idea that episodic memory is a multifaceted process.

Inversion effects in the perception of the moving human form: A comparison of adolescents with autism spectrum disorder and typically developing adolescents

The “body inversion effect” refers to superior recognition of upright than inverted images of the human body and indicates typical configural processing. Previous research by Reed et al. using static images of the human body shows that people with autism fail to demonstrate this effect. Using a novel task in which adults, adolescents with autism, and typically developing adolescents judged whether walking stick figures—created from biological motion recordings and shown at seven orientations between 0° and 180°—were normal or distorted, this study shows clear effects of stimulus inversion. Reaction times and “inverse efficiency” increased with orientation for normal but not distorted walkers, and sensitivity declined with rotation from upright for all groups. Notably, the effect of stimulus inversion was equally detrimental to both groups of adolescents suggesting intact configural processing of the body in motion in autism spectrum disorder.

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.

Impaired eye region search accuracy in children with autistic spectrum disorders

To explore mechanisms underlying reduced fixation of eyes in autism, children with Autistic Spectrum Disorders (ASD) and typically developing children were tested in five visual search experiments: simple color feature; color-shape conjunction; face in non-face objects; mouth region; and eye region. No group differences were found for reaction time profile shapes in any of the five experiments, suggesting intact basic search mechanics in children with ASD. Contrary to early reports in the literature, but consistent with other more recent findings, we observed no superiority for conjunction search in children with ASD. Importantly, children with ASD did show reduced accuracy for eye region search (p = .005), suggesting that eyes contribute less to high-level face representations in ASD or that there is an eye region-specific disruption to attentional processes engaged by search in ASD.

It's all in the eyes: subcortical and cortical activation during grotesqueness perception in autism

Atypical face processing plays a key role in social interaction difficulties encountered by individuals with autism. In the current fMRI study, the Thatcher illusion was used to investigate several aspects of face processing in 20 young adults with high-functioning autism spectrum disorder (ASD) and 20 matched neurotypical controls. "Thatcherized" stimuli were modified at either the eyes or the mouth and participants discriminated between pairs of faces while cued to attend to either of these features in upright and inverted orientation. Behavioral data confirmed sensitivity to the illusion and intact configural processing in ASD. Directing attention towards the eyes vs. the mouth in upright faces in ASD led to (1) improved discrimination accuracy; (2) increased activation in areas involved in social and emotional processing; (3) increased activation in subcortical face-processing areas. Our findings show that when explicitly cued to attend to the eyes, activation of cortical areas involved in face processing, including its social and emotional aspects, can be enhanced in autism. This suggests that impairments in face processing in autism may be caused by a deficit in social attention, and that giving specific cues to attend to the eye-region when performing behavioral therapies aimed at improving social skills may result in a better outcome.

Face identity recognition in autism spectrum disorders: a review of behavioral studies

Face recognition--the ability to recognize a person from their facial appearance--is essential for normal social interaction. Face recognition deficits have been implicated in the most common disorder of social interaction: autism. Here we ask: is face identity recognition in fact impaired in people with autism? Reviewing behavioral studies we find no strong evidence for a qualitative difference in how facial identity is processed between those with and without autism: markers of typical face identity recognition, such as the face inversion effect, seem to be present in people with autism. However, quantitatively--i.e., how well facial identity is remembered or discriminated--people with autism perform worse than typical individuals. This impairment is particularly clear in face memory and in face perception tasks in which a delay intervenes between sample and test, and less so in tasks with no memory demand. Although some evidence suggests that this deficit may be specific to faces, further evidence on this question is necessary.

Discriminating grotesque from typical faces: evidence from the Thatcher illusion

The discrimination of thatcherized faces from typical faces was explored in two simultaneous alternative forced choice tasks. Reaction times (RTs) and errors were measured in a behavioural task. Brain activation was measured in an equivalent fMRI task. In both tasks, participants were tested with upright and inverted faces. Participants were also tested on churches in the behavioural task. The behavioural task confirmed the face specificity of the illusion (by comparing inversion effects for faces against churches) but also demonstrated that the discrimination was primarily, although not exclusively, driven by attending to eyes. The fMRI task showed that, relative to inverted faces, upright grotesque faces are discriminated via activation of a network of emotion/social evaluation processing areas. On the other hand, discrimination of inverted thatcherized faces was associated with increased activation of brain areas that are typically involved in perceptual processing of faces.

Memory awareness for faces in individuals with autism

Little is known regarding metacognition in individuals with autism. Specifically, it is unclear how individuals with autism think about their own mental states. The current study assessed memory awareness during a facial recognition task. High-functioning children (M = 13.1 years, n = 18) and adults (M = 27.5 years, n = 16) with autism matched with typically developing children (M = 14.3 years, n = 13) and adults (M = 26.9 years, n = 15) were tested. Children with autism demonstrated less accurate memory awareness for faces and less reliable differentiation between their confidence ratings compared to typically developing children. Subtle impairments in memory awareness for faces were also evident in adults with autism. Results indicate that broader metacognitive deficits may exist in individuals with autism, possibly contributing to other known impairments.

Does Thompson's Thatcher Effect reflect a face-specific mechanism?

The Thatcher Illusion or Thatcher Effect (TE--Thompson 1980, Perception 9 483-484) reflects the difficulty in perceiving the local inversion of parts when the whole object, generally a face, is globally inverted. We tested the generality of the TE with a range of faces and nonface objects, and observed the TE with many non-face categories including cars, buildings, bikes, and letter strings. In terms of magnitude, the face TE is not exceptionally large compared to other object categories, and the magnitude of the TE can be predicted by performance on this task for upright stimuli, regardless of whether the object is a face or not. We did not observe evidence for a unique mechanism contributing to the TE for faces. We discuss factors that influence the magnitude of the TE, some common across domains and others more specific to a particular category.

Differential Sensitivity to Rotations of Facial Features in the Thatcher Illusion

A developmental study is presented in which participants must detect the Thatcher illusion in order to match unfamiliar faces on identity. 114 participants between 6 and 67 years of age completed a matching task whereby face pairs were presented upright or under inversion. At all ages, participants were more accurate matching upright than inverted faces. In an altered version of the Thatcher task, where only the eyes or mouth were inverted, all participants were more accurate and faster to detect eye manipulations than mouth manipulations. The results are discussed in terms of the developmental significance of face inversion, the Thatcher illusion, and the salience for protection from the Thatcher illusion.

Vision in autism spectrum disorders

Autism spectrum disorders (ASDs) are developmental disorders which are thought primarily to affect social functioning. However, there is now a growing body of evidence that unusual sensory processing is at least a concomitant and possibly the cause of many of the behavioural signs and symptoms of ASD. A comprehensive and critical review of the phenomenological, empirical, neuroscientific and theoretical literature pertaining to visual processing in ASD is presented, along with a brief justification of a new theory which may help to explain some of the data, and link it with other current hypotheses about the genetic and neural aetiologies of this enigmatic condition.

The eyes or the mouth? Feature salience and unfamiliar face processing in Williams syndrome and autism

Using traditional face perception paradigms the current study explores unfamiliar face processing in two neurodevelopmental disorders. Previous research indicates that autism and Williams syndrome (WS) are both associated with atypical face processing strategies. The current research involves these groups in an exploration of feature salience for processing the eye and mouth regions of unfamiliar faces. The tasks specifically probe unfamiliar face matching by using (a) upper or lower face features, (b) the Thatcher illusion, and (c) featural and configural face modifications to the eye and mouth regions. Across tasks, individuals with WS mirror the typical pattern of performance, with greater accuracy for matching faces using the upper than using the lower features, susceptibility to the Thatcher illusion, and greater detection of eye than mouth modifications. Participants with autism show a generalized performance decrement alongside atypicalities, deficits for utilizing the eye region, and configural face cues to match unfamiliar faces. The results are discussed in terms of feature salience, structural encoding, and the phenotypes typically associated with these neurodevelopmental disorders.

Affective response to eye contact and face recognition ability in children with ASD

This study tested the hypothesis that affective arousal in response to eye contact is negatively associated with face identification skills in children with autism spectrum disorder (ASD). Participants were 20 children and adolescents with ASD and 20 age- and IQ-matched typically developing (TD) children. Skin conductance response (SCR), a psychophysiological measure of autonomic arousal, was collected while participants viewed faces with gaze directed toward them and faces with gaze averted away from them. Participants also completed an independent match-to-sample face recognition test. Children with ASD exhibited significantly larger SCRs than TD children to faces with direct and averted gaze. There were no differences between SCRs to direct gaze and averted gaze in either group. Children with ASD exhibited a marginally significant decrease in face recognition accuracy relative to TD children, particularly when face recognition depended on the eye region of the face. Face recognition accuracy among children with ASD was negatively correlated with the amplitude of SCRs to direct gaze but not to averted gaze. There was no association between face recognition accuracy and SCRs to gaze in the TD group. These findings suggest that autonomic reactivity to eye contact may interfere with face identity processing in some children with ASD.

Mnesic imbalance: a cognitive theory about autism spectrum disorders

Autism is characterized by impairments in social interaction, communicative capacity and behavioral flexibility. Some cognitive theories can be useful for finding a relationship between these irregularities and the biological mechanisms that may give rise to this disorder. Among such theories are mentalizing deficit, weak central coherence and executive dysfunction, but none of them has been able to explain all three diagnostic symptoms of autism. These cognitive disorders may be related among themselves by faulty learning, since several research studies have shown that the brains of autistic individuals have abnormalities in the cerebellum, which plays a role in procedural learning. In keeping with this view, one may postulate the possibility that declarative memory replaces faulty procedural memory in some of its functions, which implies making conscious efforts in order to perform actions that are normally automatic. This may disturb cognitive development, resulting in autism symptoms. Furthermore, this mnesic imbalance is probably involved in all autism spectrum disorders. In the present work, this theory is expounded, including preliminary supporting evidence.

Brief report: face configuration accuracy and processing speed among adults with high-functioning autism spectrum disorders

The present study investigates the accuracy and speed of face processing employed by high-functioning adults with autism spectrum disorders (ASDs). Two behavioral experiments measured sensitivity to distances between features and face recognition when performance depended on holistic versus featural information. Results suggest adults with ASD were less accurate, but responded as quickly as controls for both tasks. In contrast to previous findings with children, adults with ASD demonstrated a holistic advantage only when the eye region was tested. Both groups recognized large manipulations to second-order relations more accurately than no change or small changes, but controls responded more quickly than participants with ASD when recognizing these large manipulations to configural information.

Brief report: perception of body posture--what individuals with autism spectrum disorder might be missing

Autism has been associated with atypical face and configural processing, as indicated by the lack of a face inversion effect (better recognition of upright than inverted faces). We investigated whether such atypical processing was restricted to the face or extended to social information found in body postures. An inversion paradigm compared recognition of upright and inverted faces, body postures, and houses. Typical adults demonstrated inversion effects for both faces and body postures, but adults with autism demonstrated only a face inversion effect. Adults with autism may not have a configural processing deficit per se, but instead may have strategies for recognizing faces not used for body postures. Results have implications for therapies employing training in imitation and body posture perception.

Differences in discrimination of eye and mouth displacement in autism spectrum disorders

Individuals with Autism Spectrum Disorders (ASD) have been found to have impairments in some face recognition tasks [e.g., Boucher, J., & Lewis, V. (1992). Unfamiliar face recognition in relatively able autistic children. Journal of Child Psychology and Psychiatry, 33, 843-859.], and it has been suggested that this impairment occurs because these individuals do not spontaneously attend to the eyes [e.g., Pelphrey, K. A., Sasson, N. J., Reznick, J. S., Paul, G., Goldman, B. D., & Piven, J. (2002). Visual scanning of faces in autism. Journal of Autism and Developmental Disorders, 32, 249-261.], or attend selectively to the mouth [e.g., Langdell, T. (1978). Recognition of faces-approach to study of autism. Journal of Child Psychology and Psychiatry and Allied Disciplines, 19, 255-268; Joseph, R. M., & Tanaka J. (2003). Holistic and part-based face recognition in children with autism. Journal of Child Psychology and Psychiatry, 44, 529-542.]. Here, we test whether the eyes or the mouth are attended to preferentially by 16 males with ASD and 19 matched controls. Participants discriminated small spatial displacements of the eyes and the mouth. If the mouth region were attended to preferentially by individuals with ASD, we would expect ASD observers to be better at detecting subtle changes in mouth than eye displacements, relative to controls. Further, following Barton [Barton, J. J. S., Keenan, J. P., & Bass, T. (2001). Discrimination of spatial relations and features in faces: Effects of inversion and viewing duration. British Journal of Psychology, 92, 527-549.], we would expect to see differences in inversion effects as a function of feature manipulation between ASD and control groups. We found that individuals with ASD performed significantly differently than controls for the eye, but not the mouth, trials. However, we found no difference in inversion effects between the two groups of observers. Furthermore, we found evidence of distinct subclasses of individuals with ASD: those who performed normally, and those who were impaired. These results suggests that typical individuals are better able to make use of information in the eyes than some individuals with ASD, but that there is no clear autism "advantage" in the use of information in the mouth region.

The weak coherence account: detail-focused cognitive style in autism spectrum disorders

"Weak central coherence" refers to the detail-focused processing style proposed to characterise autism spectrum disorders (ASD). The original suggestion of a core deficit in central processing resulting in failure to extract global form/meaning, has been challenged in three ways. First, it may represent an outcome of superiority in local processing. Second, it may be a processing bias, rather than deficit. Third, weak coherence may occur alongside, rather than explain, deficits in social cognition. A review of over 50 empirical studies of coherence suggests robust findings of local bias in ASD, with mixed findings regarding weak global processing. Local bias appears not to be a mere side-effect of executive dysfunction, and may be independent of theory of mind deficits. Possible computational and neural models are discussed.

Familiar Face Recognition in Children with Autism: The Differential use of Inner and Outer Face Parts

We investigated whether children with autistic spectrum disorders (ASD) have a deficit in recognising familiar faces. Children with ASD were given a forced choice familiar face recognition task with three conditions: full faces, inner face parts and outer face parts. Control groups were children with developmental delay (DD) and typically developing (TD) children. Children with ASD and children with DD recognised slightly fewer faces than did TD children, but there was no ASD-specific deficit. All groups displayed the dame pattern of face part superiority: full-face superiority over inner face, and inner face superiority over outer face. Thererfore, the pattern of familiar face recognition by children with ASD was similar to the pattern found in other children.

Configural processing in autism and its relationship to face processing

Studies of the perceptual performance of individuals with autism have focused, to a large extent, on two domains of visual behavior, one associated with face processing and the other associated with global or holistic processing. Whether autistic individuals differ from neurotypical individuals in these domains is debatable and, moreover, the relationship between the behaviors in these two domains remains unclear. We first compared the face processing ability of 14 adult individuals with autism with that of neurotypical controls and showed that the autistic individuals were slowed in their speed of face discrimination. We then showed that the two groups differed in their ability to derive the global whole in two different tasks, one using hierarchical compound letters and the other using a microgenetic primed matching task with geometric shapes, with the autistic group showing a bias in favor of local information. A significant correlation was also observed between performance on the face task and the configural tasks. We then confirmed the prediction that the ability to derive the global whole is not only critical for faces but also for other objects as well, as the autistic individuals performed more slowly than the control group in discriminating between objects. Taken together, the results suggest that the bias for local processing seen in autistic individuals might have an adverse impact on their ability to process faces and objects.

Impaired Face Processing in Autism: Fact or Artifact?

Within the last 10 years, there has been an upsurge of interest in face processing abilities in autism which has generated a proliferation of new empirical demonstrations employing a variety of measuring techniques. Observably atypical social behaviors early in the development of children with autism have led to the contention that autism is a condition where the processing of social information, particularly faces, is impaired. While several empirical sources of evidence lend support to this hypothesis, others suggest that there are conditions under which autistic individuals do not differ from typically developing persons. The present paper reviews this bulk of empirical evidence, and concludes that the versatility and abilities of face processing in persons with autism have been underestimated.