Flexible Visual Processing in Young Adults with Autism: The Effects of Implicit Learning on a Global–Local Task

Active Viewing Facilitates Gaze to the Eye Region in Young Children with Autism Spectrum Disorder

Previous studies have shown reduced attention to the eyes in individuals with autism spectrum disorder (ASD). However, most eye-tracking evidence regarding this impairment has been derived from passive viewing tasks. Here, we compared the passive viewing of faces with an active task involving face identification with morphing faces. While typical controls prioritized the eyes over other facial features regardless of viewing condition, autistic children exhibited reduced eye-looking in passive viewing, but displayed increased attention allocation to the eyes when instructed to identify faces. The proportional eye-looking in ASD during facial recognition was negatively related to the autism symptoms severity. These findings provide evidence regarding the specific situations in which diminished eye-looking may rise in young ASD children.

The autistic brain can process local but not global emotion regularities in facial and musical sequences

Whether autism spectrum disorder (ASD) is associated with a global processing deficit remains controversial. Global integration requires extraction of regularity across various timescales, yet little is known about how individuals with ASD process regularity at local (short timescale) versus global (long timescale) levels. To this end, we used event-related potentials to investigate whether individuals with ASD would show different neural responses to local (within trial) versus global (across trials) emotion regularities extracted from sequential facial expressions; and if so, whether this visual abnormality would generalize to the music (auditory) domain. Twenty individuals with ASD and 21 age- and IQ-matched individuals with typical development participated in this study. At an early processing stage, ASD participants exhibited preserved neural responses to violations of local emotion regularity for both faces and music. At a later stage, however, there was an absence of neural responses in ASD to violations of global emotion regularity for both faces and music. These findings suggest that the autistic brain responses to emotion regularity are modulated by the timescale of sequential stimuli, and provide insight into the neural mechanisms underlying emotional processing in ASD.

Responses to Navon tasks differ across development and between tasks with differing attentional demands

Navon hierarchical stimuli are designed to measure responses to the global level (grouped local elements, e.g. a forest) and the local level (individuated local elements, e.g. trees) of a visual scene. Cross-sectional evidence suggests that there are developmental changes in global and local processing. We examined global and local processing in 135 typically developing children in Year 1 (aged 5-6 year), Year 3 (aged 7-8 years), and Year 5 (aged 9-10 years). Participants completed a range of Navon tasks, each with different attentional demands. The design of the Navon stimuli remained constant across the tasks, ensuring that any task-related differences were not due to stimulus characteristics. Sixty children from Years 1 and 3 repeated the testing session two years later. Linear mixed model analyses combined longitudinal and cross-sectional data to assess developmental changes and the influence of attentional task demands on responses. The results revealed differing patterns of global and local processing responses according to Year group and attentional task demands. We found some evidence of developmental change in responses from a relatively more local advantage to a relatively more global advantage, which is consistent with the literature. However, the age at which this transition occurred varied across the tasks. We conclude that responses to hierarchical Navon stimuli are modulated by attentional task characteristics which mask any underlying global or local processing advantage.

Characteristic Executive Dysfunction for High-Functioning Autism Sustained to Adulthood

The comprehensiveness and severity of executive dysfunction in high-functioning autism (HFA) spectrum disorder have not reached a unified conclusion especially in patients in adulthood. Clarifying this issue is critical for guiding clinical diagnosis and targeted intervention. The primary objective of the present meta-analysis was to study the characteristics of executive function (EF) in adults with HFA compared to typically developing (TD) adults, by taking five key components into consideration, including inhibition, working memory, flexibility, planning, and fluency. The PubMed and Embase databases were searched to identify peer-reviewed studies that compared EF in adults with and without HFA from 1980 to November 2018. Hedges' g effect sizes were computed to measure the primary outcome. Moderators like age, sex, and diagnostic tools were controlled using meta-regressions. Forty-two studies satisfying the selection criteria were included, which resulted in a large sample size of 2419 participants. A moderate overall effect size for reduced EF across domains was found in adults with HFA, compared with TD (g = 0.57, 95% confidence interval 0.47-0.66). Subsequently, a broad executive dysfunction was found in adults with HFA in this study (flexibility [g = 0.69], planning [g = 0.64], inhibition [g = 0.61], working memory [g = 0.48], fluency [g = 0.42]), with the predominated impairment on flexibility and planning. Taken together, these results provide evidence for the executive dysfunction hypothesis and may assist in the clinical diagnosis and targeted intervention, suggesting the necessity of sustained intervention on EF for individuals with HFA from childhood to adulthood. LAY SUMMARY: The meta-analysis explored the characteristics of EF in adults with high-functioning autism (HFA) comparing to typically developing controls. Moderate effect sizes for reduced EF across domains were found in adults with HFA, with the flexibility and planning being the most predominately impaired. A comprehensive measurement of EF in adults with HFA has important clinical implications for the diagnosis, treatment, prognosis, and a fundamental understanding for developmental trajectory of these patients.

iPads for Teaching Graphic Symbols to People With Autism Spectrum Disorder

Individuals with low functioning autism spectrum disorders (LFASD) who demonstrate significant cognitive and communication needs benefit from using technology for learning graphic symbols for enhancing participation. This study investigated if an iPad application would increase identification of graphic symbols by children and adults with LFASD. Adults and children with LFASD used an application to learn 15 graphic symbols. Participants were able to focus for the duration of the activity and use the educational software for learning graphic symbols. By the end to the study, 50% of the participants in both groups recognized the meaning of more symbols after intervention. iPad use enabled control of the stimulus by reducing communication barriers, which increased participants' ability to learn symbols. Even participants with little ability to focus were able to complete the whole activity. Technology enabled learning of most of the symbols though the specially created application.

A Developmental Perspective of Global and Local Visual Perception in Autism Spectrum Disorder

Individuals with autism spectrum disorder (ASD) demonstrate superior performances on visuo-spatial tasks emphasizing local information processing; however, findings from studies involving hierarchical stimuli are inconsistent. Wide age ranges and group means complicate their interpretability. Children and adolescents with and without ASD completed a Navon task wherein they identified global and local stimuli composed of either consistent or inconsistent letters. Trajectories of reaction time in global and local conditions were similar within and between groups when consistent and inconsistent stimuli were considered together, but the effect of local-to-global interference was significantly higher in participants with than without ASD. Age was not a significant predictor of local-to-global interference, suggesting that this effect emerges in childhood and persists throughout adolescence in ASD.

An investigation of global-local processing bias in a large sample of typical individuals varying in autism traits

Although individuals with an autism spectrum disorder display impaired function across several social and behavioral domains, they possess intact, and often superior visual processing abilities for local relative to global aspects of their visual environment. To address whether differences in visual processing similarly vary within typical individuals as a function of their level of social competence, using the Navon hierarchical figures task, here we examined the relationship between global-local visual processing style and the number of autism-like traits in a large sample of 434 typically developed persons. In line with the existing literature, our data indicated an overall global processing bias. However, this overall visual processing style did not vary with participants' number of autism-like traits. These results suggest that the visual processing of Navon figures may be different in typical individuals vs. those with an autism spectrum disorder, with those differences potentially reflecting specific stimulus and task settings.

Hierarchical Letters in ASD: High Stimulus Variability Under Different Attentional Modes

Studies using hierarchical patterns to test global precedence and local-global interference in individuals with ASD have produced mixed results. The current study focused on stimulus variability and locational uncertainty, while using different attentional modes. Two groups of 44 children with and without ASD completed a divided attention task as well as a global and local selective attention task. The results revealed global-to-local and local-to-global interference in ASD, to the same extent as in the TD group. Both groups struggled with the same type of stimuli (i.e., ignoring the global level information) and performed similar in all three tasks. Future studies on (visual) information processing in ASD should pursue the impact of stimulus noise and trial-by-trial uncertainty further.

Atypical Gaze Cueing Pattern in a Complex Environment in Individuals with ASD

Clinically, social interaction, including gaze-triggered attention, has been reported to be impaired in autism spectrum disorder (ASD), but psychological studies have generally shown intact gaze-triggered attention in ASD. These studies typically examined gaze-triggered attention under simple environmental conditions. In real life, however, the environment is complex. Previous studies have shown that an enhanced cueing effect was found when using eye gaze compared with arrow cues in unpredictably complex conditions in typically developing (TD) individuals. However, in the current study, compared with TD individuals, the cueing effect failed to enhance when using eye gaze compared with arrow cues under complex conditions in individuals with ASD. This may reflect the atypical style of gaze-triggered attention when individuals with ASD adapt to environmental complexity.

Effects of Age and Attention on Auditory Global-Local Processing in Children with Autism Spectrum Disorder

In vision, typically-developing (TD) individuals perceive "global" (whole) before "local" (detailed) features, whereas individuals with autism spectrum disorder (ASD) exhibit a local bias. However, auditory global-local distinctions are less clear in ASD, particularly in terms of age and attention effects. To these aims, here ASD and TD children judged local and global pitch structure in nine-tone melodies. Both groups showed a similar global precedence effect, but ASD children were less sensitive to global interference than TD children at younger ages. There was no effect of attention task. These findings provide novel evidence of developmental differences in auditory perception and may help to refine sensory phenotypes in ASD.

Context processing in adolescents with autism spectrum disorder: How complex could it be?

The ability of individuals with Autism Spectrum Disorder (ASD) to process context has long been debated: According to the Weak Central Coherence theory, ASD is characterized by poor global processing, and consequently-poor context processing. In contrast, the Social Cognition theory argues individuals with ASD will present difficulties only in social context processing. The complexity theory of autism suggests context processing in ASD will depend on task complexity. The current study examined this controversy through two priming tasks, one presenting human stimuli (facial expressions) and the other presenting non-human stimuli (animal faces). Both tasks presented visual targets, preceded by congruent, incongruent, or neutral auditory primes. Local and global processing were examined by presenting the visual targets in three spatial frequency conditions: High frequency, low frequency, and broadband. Tasks were administered to 16 adolescents with high functioning ASD and 16 matched typically developing adolescents. Reaction time and accuracy were measured for each task in each condition. Results indicated that individuals with ASD processed context for both human and non-human stimuli, except in one condition, in which human stimuli had to be processed globally (i.e., target presented in low frequency). The task demands presented in this condition, and the performance deficit shown in the ASD group as a result, could be understood in terms of cognitive overload. These findings provide support for the complexity theory of autism and extend it. Our results also demonstrate how associative priming could support intact context processing of human and non-human stimuli in individuals with ASD. Autism Res 2017, 10: 520-530. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

A Developmental Perspective of Global and Local Visual Perception in Autism Spectrum Disorder

Individuals with autism spectrum disorder (ASD) demonstrate superior performances on visuo-spatial tasks emphasizing local information processing; however, findings from studies involving hierarchical stimuli are inconsistent. Wide age ranges and group means complicate their interpretability. Children and adolescents with and without ASD completed a Navon task wherein they identified global and local stimuli composed of either consistent or inconsistent letters. Trajectories of reaction time in global and local conditions were similar within and between groups when consistent and inconsistent stimuli were considered together, but the effect of local-to-global interference was significantly higher in participants with than without ASD. Age was not a significant predictor of local-to-global interference, suggesting that this effect emerges in childhood and persists throughout adolescence in ASD.

Visual attention shifting in autism spectrum disorders

INTRODUCTION

Abnormal visual attention has been frequently observed in autism spectrum disorders (ASD). Abnormal shifting of visual attention is related to abnormal development of social cognition and has been identified as a key neuropsychological finding in ASD. Better characterizing attention shifting in ASD and its relationship with social functioning may help to identify new targets for intervention and improving social communication in these disorders. Thus, the current study investigated deficits in attention shifting in ASD as well as relationships between attention shifting and social communication in ASD and neurotypicals (NT).

METHOD

To investigate deficits in visual attention shifting in ASD, 20 ASD and 20 age- and gender-matched NT completed visual search (VS) and Navon tasks with attention-shifting demands as well as a set-shifting task. VS was a feature search task with targets defined in one of two dimensions; Navon required identification of a target letter presented at the global or local level. Psychomotor and processing speed were entered as covariates. Relationships between visual attention shifting, set shifting, and social functioning were also examined.

RESULTS

ASD and NT showed comparable costs of shifting attention. However, psychomotor and processing speed were slower in ASD than in NT, and psychomotor and processing speed were positively correlated with attention-shifting costs on Navon and VS, respectively, for both groups. Attention shifting on VS and Navon were correlated among NT, while attention shifting on Navon was correlated with set shifting among ASD. Attention-shifting costs on Navon were positively correlated with restricted and repetitive behaviors among ASD.

CONCLUSIONS

Relationships between attention shifting and psychomotor and processing speed, as well as relationships between measures of different aspects of visual attention shifting, suggest inefficient top-down influences over preattentive visual processing in ASD. Inefficient attention shifting may be related to restricted and repetitive behaviors in these disorders.

Implicit learning in individuals with autism spectrum disorders: a meta-analysis

BACKGROUND

Individuals with autism spectrum disorders (ASDs) are characterized by social communication difficulties and behavioural rigidity. Difficulties in learning from others are one of the most devastating features of this group of conditions. Nevertheless, the nature of learning difficulties in ASDs is still unclear. Given the relevance of implicit learning for social and communicative functioning, a link has been hypothesized between ASDs and implicit learning deficit. However, studies that have employed formal testing of implicit learning in ASDs provided mixed results.

METHOD

We undertook a systematic search of studies that examined implicit learning in ASDs using serial reaction time (SRT), alternating serial reaction time (ASRT), pursuit rotor (PR), and contextual cueing (CC) tasks, and synthesized the data using meta-analysis. A total of 11 studies were identified, representing data from 407 individuals with ASDs and typically developing comparison participants.

RESULTS

The results indicate that individuals with ASDs do not differ in any task considered [SRT and ASRT task: standardized mean difference (SMD) -0.18, 95% confidence interval (CI) -0.71 to 0.36; PR task: SMD -0.34, 95% CI -1.04 to 0.36; CC task: SMD 0.27, 95% CI -0.07 to 0.60].

CONCLUSIONS

Based on our synthesis of the existing literature, we conclude that individuals with ASDs can learn implicitly, supporting the hypothesis that implicit learning deficits do not represent a core feature in ASDs.

Orientation-specific surround suppression in the primary visual cortex varies as a function of autistic tendency

Individuals with autism spectrum disorder (ASD) exhibit superior performance on tasks that rely on local details in an image, and they exhibit deficits in tasks that require integration of local elements into a unified whole. These perceptual abnormalities have been proposed to underlie many of the characteristic features of ASD, but the underlying neural mechanisms are poorly understood. Here, we investigated the degree to which orientation-specific surround suppression, a well-known form of contextual modulation in visual cortex, is associated with autistic tendency in neurotypical (NT) individuals. Surround suppression refers to the phenomenon that the response to a stimulus in the receptive field of a neuron is suppressed when it is surrounded by stimuli just outside the receptive field. The suppression is greatest when the center and surrounding stimuli share perceptual features such as orientation. Surround suppression underlies a number of fundamental perceptual processes that are known to be atypical in individuals with ASD, including perceptual grouping and perceptual pop-out. However, whether surround suppression in the primary visual cortex (V1) is related to autistic traits has not been directly tested before. We used fMRI to measure the neural response to a center Gabor when it was surrounded by Gabors having the same or orthogonal orientation, and calculated a suppression index (SI) for each participant that denoted the magnitude of suppression in the same vs. orthogonal conditions. SI was positively correlated with degree of autistic tendency in each individual, as measured by the Autism Quotient (AQ) scale, a questionnaire designed to assess autistic traits in the general population. Age also correlated with SI and with autistic tendency in our sample, but did not account for the correlation between SI and autistic tendency. These results suggest a reduction in orientation-specific surround suppression in V1 with increasing autistic tendency.

From local to global processing: the development of illusory contour perception

Global visual processing is important for segmenting scenes, extracting form from background, and recognizing objects. Local processing involves attention to the local elements, contrast, and boundaries of an image at the expense of extracting a global percept. Previous work is inconclusive regarding the relative development of local and global processing. Some studies suggest that global perception is already present by 8 months of age, whereas others suggest that the ability arises during childhood and continues to develop during adolescence. We used a novel method to assess the development of global processing in 3- to 10-year-old children and an adult comparison group. We used Kanizsa illusory contours as an assay of global perception and measured responses on a touch-sensitive screen while monitoring eye position with a head-mounted eye tracker. Participants were tested using a similarity match-to-sample paradigm. Using converging measures, we found a clear developmental progression with age such that the youngest children performed near chance on the illusory contour discrimination, whereas 7- and 8-year-olds performed nearly perfectly, as did adults. There was clear evidence of a gradual shift from a local processing strategy to a global one; young children looked predominantly at and touched the "pacman" inducers of the illusory form, whereas older children and adults looked predominantly at and touched the middle of the form. These data show a prolonged developmental trajectory in appreciation of global form, with a transition from local to global visual processing between 4 and 7 years of age.

Visuospatial processing in children with autism: no evidence for (training-resistant) abnormalities

Individuals with autism spectrum disorders (ASDs) have been assumed to show evidence of abnormal visuospatial processing, which has been attributed to a failure to integrate local features into coherent global Gestalts and/or to a bias towards local processing. As the available data are based on baseline performance only, which does not provide insight into cognitive/neural plasticity and actual cognitive potential, we investigated how training-resistant possible visuospatial processing differences between children with and without ASD are. In particular, we studied the effect of computerized versus face-to-face visuospatial training in a group of normally intelligent children with ASD and typically developing children as control. Findings show that (a) children with and without ASD do not differ much in visuospatial processing (as assessed by a tangram-like task) and the few differences we observed were all eliminated by training; (b) training can improve visuospatial processing (equally) in both children with ASD and normally developing children; and (c) computer-based and face-to-face training was equally effective.

Global/local processing in autism: not a disability, but a disinclination

It is widely suggested that ASD is characterized by atypical local/global processing, but the published findings are contradictory. In an effort to resolve this question, we tested a large group of children on both a free-choice task and an instructed task using hierarchical local-global stimuli. We find that although children with autism showed a reduced preference to report global properties of a stimulus when given a choice, their ability to process global properties when instructed to do so is unimpaired. These findings support prior claims that people with ASD show a disinclination, not a disability, in global processing, and highlight the broader question of whether other characteristics of autism may also reflect disinclinations rather than disabilities.

A review of intentional and cognitive control in autism

Different clinical studies have provided empirical evidence for impairments in cognitive control in individuals with autism spectrum disorders (ASD). The challenge arises, however, when trying to specify the neurocognitive mechanisms behind the reported observations of deviant patterns of goal-directed behavior in ASD. Studies trying to test specific assumptions by applying designs that are based on a more controlled experimental conditions often fail in providing strong evidence for an impairment in specific cognitive functions. In this review, we summarize and critically reflect on behavioral findings and their theoretical explanations regarding cognitive control processing in autism, also from a developmental perspective. The specific focus of this review is the recent evidence of deficits in intentional control – a specific subset of cognitive control processes that biases the choice of our behavioral goals – coming from different research fields. We relate this evidence to the cognitive rigidity observed in ASD and argue that individuals with ASD experience problems at the intentional level rather than at the level of implementation of intentions. Both these processes are related to cognitive control mechanisms but in different ways. Finally, we discuss new directions in studying cognitive control in ASD and how these relate to adaptive cognition.