Atypical shape bias and categorization in autism: Evidence from children and computational simulations

The shape bias, a preference for mapping new word labels onto the shape rather than the color or texture of referents, has been postulated as a word‐learning mechanism. Previous research has shown deficits in the shape bias in children with autism even though they acquire sizeable lexicons. While previous explanations have suggested the atypical use of color for label extension in individuals with autism, we hypothesize an atypical mapping of novel labels to novel objects, regardless of the physical properties of the objects. In Experiment 1, we demonstrate this phenomenon in some individuals with autism, but the novelty of objects only partially explains their lack of shape bias. In a second experiment, we present a computational model that provides a developmental account of the shape bias in typically developing children and in those with autism. This model is based on theories of neurological dysfunctions in autism, and it integrates theoretical and empirical findings in the literature of categorization, word learning, and the shape bias. The model replicates the pattern of results of our first experiment and shows how individuals with autism are more likely to categorize experimental objects together on the basis of their novelty. It also provides insights into possible mechanisms by which children with autism learn new words, and why their word referents may be idiosyncratic. Our model highlights a developmental approach to autism that emphasizes deficient representations of categories underlying an impaired shape bias.     

fNIRS在自闭症脑功能研究中的应用与展望

社会交往能力是人类生存的基本技能。社交能力的缺失会导致严重的行为障碍和精神疾病,如自闭症。由于自闭症儿童的特殊性,绝大多数的自闭症脑成像研究多集中在年龄较大的高功能自闭症儿童在静息态或简单的任务态下的脑激活模式或功能连接状态。自闭症的核心症状—社会交往障碍和语言交流障碍却较少有研究触及。近年来,近红外光学脑功能成像技术的发展为我们在真实的交流和互动中研究自闭症儿童的神经病理机制提供了新的工具和机遇。     

Selective Attention and Perceptual Load in Autism Spectrum Disorder

ABSTRACT— It has been suggested that the locus of selective attention (early vs. late in processing) is dependent on the perceptual load of the task. When perceptual load is low, irrelevant distractors are processed (late selection), whereas when perceptual load is high, distractor interference disappears (early selection). Attentional abnormalities have long been reported within autism spectrum disorder (ASD), and this study is the first to examine the effect of perceptual load on selective attention in this population. Fourteen adults with ASD and 23 adults without ASD performed a selective attention task with varying perceptual loads. Compared with the non-ASD group, the ASD group required higher levels of perceptual load to successfully ignore irrelevant distractors; moreover, the ASD group did not show any general reduction in performance speed or accuracy. These results suggest enhanced perceptual capacity in the ASD group and are consistent with previous observations regarding superior visual search abilities among individuals with ASD.     

Attributing social and physical meaning to ambiguous visual displays in individuals with higher-functioning autism spectrum disorders

The weak central coherence (WCC) account of autism characterizes the learning style of individuals with this condition as favoring localized and fragmented (to the detriment of global and integrative) processing of information. This pattern of learning is thought to lead to deficits in aspects of perception (e.g., face processing), cognition, and communication (e.g., focus on disjointed details rather than "gist" or context), ultimately leading to social impairments. This study was carried out to examine whether WCC applies to social and to non-social aspects of learning alike, or, alternatively, some areas of learning (e.g., physical reasoning) are spared in autism. classic social animation as quantified in the Social Attribution Task (SAT) () and a novel animation involving physical reasoning (the Physical Attribution Task; PAT) were used to test the domain specificity of the WCC hypothesis. A pilot study involving a reference group of typically developing young adults and a group of individuals with higher-functioning autism spectrum disorders (ASDs) revealed gender differences in the reference group in regards to performance on the PAT (males outperformed females). In a follow-up case-control comparison involving only males where the ASD group was matched on age and IQ to a typically developing (TD) group of children, adolescents, and adults, the ASD group showed lower SAT scores and comparable PAT scores relative to the TD group. The interaction of diagnostic group by task was highly significant, with little overlap between the groups in the distributions of SAT minus PAT scores. These results indicated preserved integrative skills in the area of physical attribution in the ASD group, thus failing to support the WCC account as a domain-independent (or more general) model of learning in autism, while highlighting the centrality of the social deficits in the characterization of learning style in the autism spectrum disorders.     

孤独症儿童的情绪共情能力及情绪表情注意方式

研究探讨了孤独症儿童的情绪共情能力及情绪表情注意方式的特点。各选取15名孤独症儿童以及作为对照组的智力障碍儿童和普通儿童各15名, 完成情绪共情实验, 同时使用生物反馈仪记录自主生理反应, 眼动仪记录眼动轨迹。结果发现孤独症儿童对情绪表情的自动模仿及感知能力显著低于智力障碍儿童与普通儿童; 对面孔的总注视时间、总注视点数均显著少于智力障碍儿童、普通儿童; 对眼部、嘴部的注视时间比及注视点数比均显著低于普通儿童; 对高兴和悲伤表情的注意较多而对恐惧则较少。这提示孤独症儿童的情绪共情能力不足、对情绪表情的注意方式异常。     

Facial Emotion Recognition in Autism Spectrum Disorders: A Review of Behavioral and Neuroimaging Studies

Behavioral studies of facial emotion recognition (FER) in autism spectrum disorders (ASD) have yielded mixed results. Here we address demographic and experiment-related factors that may account for these inconsistent findings. We also discuss the possibility that compensatory mechanisms might enable some individuals with ASD to perform well on certain types of FER tasks in spite of atypical processing of the stimuli, and difficulties with real-life emotion recognition. Evidence for such mechanisms comes in part from eye-tracking, electrophysiological, and brain imaging studies, which often show abnormal eye gaze patterns, delayed event-related-potential components in response to face stimuli, and anomalous activity in emotion-processing circuitry in ASD, in spite of intact behavioral performance during FER tasks. We suggest that future studies of FER in ASD: 1) incorporate longitudinal (or cross-sectional) designs to examine the developmental trajectory of (or age-related changes in) FER in ASD and 2) employ behavioral and brain imaging paradigms that can identify and characterize compensatory mechanisms or atypical processing styles in these individuals.     

社会动机理论视角下自闭症谱系障碍者的社交缺陷

社交缺陷是自闭症谱系障碍的核心症状。以往研究更多从社会认知的角度指出该症状是心理理论损伤所致, 但自闭症谱系障碍个体在获得心理理论之前已表现出社会动机不足的特质, 且部分能通过心理理论测试的个体依旧表现出社会动机不足的特点。社会动机理论指出社会动机是促进人类进化、激发和维持个体社会性活动的重要内部动力, 自闭症谱系障碍者的社交缺陷是由于社会动机不足所致。该理论从行为表现、神经科学和生物学三个方面对自闭症谱系障碍者的社交缺陷进行解释。未来应进一步完善自闭症谱系障碍个体社会动机的神经机制研究, 明确社会动机理论在自闭症谱系障碍群体中的适用范围, 探究社会动机理论在评估诊断和临床康复中的应用价值。     

A threat-detection advantage in those with autism spectrum disorders

Identifying threatening expressions is a significant social perceptual skill. Individuals with autism spectrum disorders (ASD) are impaired in social interaction, show deficits in face and emotion processing, show amygdala abnormalities and display a disadvantage in the perception of social threat. According to the anger superiority hypothesis, angry faces capture attention faster than happy faces in individuals with a history of typical development [Hansen, C. H., & Hansen, R. D. (1988). Finding the face in the crowd: An anger superiority effect. Journal of Personality and Social Psychology, 54(6), 917–924]. We tested threat detection abilities in ASD using a facial visual search paradigm. Participants were asked to detect an angry or happy face image in an array of distracter faces. A threat-detection advantage was apparent in both groups: participants showed faster and more accurate detection of threatening over friendly faces. Participants with ASD showed similar reaction time, but decreased overall accuracy compared to controls. This provides evidence for less robust, but intact or learned implicit processing of basic emotions in ASD.     

Procedural learning across the lifespan: A systematic review with implications for atypical development

This systematic review aimed to investigate procedural learning across the lifespan in typical and atypical development. Procedural learning is essential for the development of everyday skills, including language and communication skills. Although procedural learning efficiency has been extensively studied, there is no consensus yet on potential procedural learning changes during development and ageing. Currently, three conflicting models regarding this trajectory exist: (1) a model of age invariance; (2a) a model with a peak in young adulthood; and (2b) a model with a plateau in childhood followed by a decline. The aims of this study were (1) to investigate this debate on procedural learning across the lifespan by systematically reviewing evidence for each model from studies using the serial reaction time task; and (2) to review procedural learning in autism spectrum disorder (ASD) and specific language impairment (SLI), two developmental disorders characterized by deficits in communication skills, in the light of these models. Our findings on typical development strongly support a model of age-related changes (Model 2a or 2b) and show that mixed findings regarding the developmental trajectory during childhood can be explained by methodological differences across studies. Applying these conclusions to systematic reviews of studies of ASD and SLI makes it clear that there is a strong need for the inclusion of multiple age groups in these clinical studies to model procedural learning in atypical development. Clinical implications of the findings are discussed. Future research should focus on the role of declarative learning in both typical and atypical development.     

Teaching children with autism spectrum disorder to tact olfactory stimuli

Research on tact acquisition by children with autism spectrum disorder (ASD) has often focused on teaching participants to tact visual stimuli. It is important to evaluate procedures for teaching tacts of nonvisual stimuli (e.g., olfactory, tactile). The purpose of the current study was to extend the literature on secondary target instruction and tact training by evaluating the effects of a discrete‐trial instruction procedure involving (a) echoic prompts, a constant prompt delay, and error correction for primary targets; (b) inclusion of secondary target stimuli in the consequent portion of learning trials; and (c) multiple exemplar training on the acquisition of item tacts of olfactory stimuli, emergence of category tacts of olfactory stimuli, generalization of category tacts, and emergence of category matching, with three children diagnosed with ASD. Results showed that all participants learned the item and category tacts following teaching, participants demonstrated generalization across category tacts, and category matching emerged for all participants.     

Outcomes of a practical approach for improving conversation skills in adults with autism

Many individuals with autism spectrum disorder (ASD) have deficits in conversation skills that can interfere with the development of personal and professional relationships. Further research is needed on efficient interventions for targeting conversation skills in adults with ASD and for evaluating the social validity of the outcomes. In this study, 2 practitioners implemented a 4‐week training program for 5 adults with ASD that combined individualized computer‐based instruction (CBI) and practice with peers to promote the acquisition, maintenance, and generalization of conversation skills. Training was associated with improvements in 12 of 13 skills across participants. These findings, along with peer ratings of the participants' conversation skills, suggest that this model is a promising, socially valid approach for improving conversation skills in adults with ASD.     

Perceptual similarity in autism

People with autism have consistently been found to outperform controls on visuo-spatial tasks such as block design, embedded figures, and visual search tasks. Plaisted, O'Riordan, and others (Bonnel et al., 2003; O'Riordan & Plaisted, 2001; O'Riordan, Plaisted, Driver, & Baron-Cohen, 2001; Plaisted, O'Riordan, & Baron-Cohen, 1998a, 1998b) have suggested that these findings might be explained in terms of reduced perceptual similarity in autism, and that reduced perceptual similarity could also account for the difficulties that people with autism have in making generalizations to novel situations. In this study, high-functioning adults with autism and ability-matched controls performed a low-level categorization task designed to examine perceptual similarity. Results were analysed using standard statistical techniques and modelled using a quantitative model of categorization. This analysis revealed that participants with autism required reliably longer to learn the category structure than did the control group but, contrary to the predictions of the reduced perceptual similarity hypothesis, no evidence was found of more accurate performance by the participants with autism during the generalization stage. Our results suggest that when all participants are attending to the same attributes of an object in the visual domain, people with autism will not display signs of enhanced perceptual similarity.     

Mechanisms of developmental regression in autism and the broader phenotype: a neural network modeling approach

Loss of previously established behaviors in early childhood constitutes a markedly atypical developmental trajectory. It is found almost uniquely in autism and its cause is currently unknown (Baird et al., 2008). We present an artificial neural network model of developmental regression, exploring the hypothesis that regression is caused by overaggressive synaptic pruning and identifying the mechanisms involved. We used a novel population-modeling technique to investigate developmental deficits, in which both neurocomputational parameters and the learning environment were varied across a large number of simulated individuals. Regression was generated by the atypical setting of a single pruning-related parameter. We observed a probabilistic relationship between the atypical pruning parameter and the presence of regression, as well as variability in the onset, severity, behavioral specificity, and recovery from regression. Other neurocomputational parameters that varied across the population modulated the risk that an individual would show regression. We considered a further hypothesis that behavioral regression may index an underlying anomaly characterizing the broader autism phenotype. If this is the case, we show how the model also accounts for several additional findings: shared gene variants between autism and language impairment (Vernes et al., 2008); larger brain size in autism but only in early development (Redcay & Courchesne, 2005); and the possibility of quasi-autism, caused by extreme environmental deprivation (Rutter et al., 1999). We make a novel prediction that the earliest developmental symptoms in the emergence of autism should be sensory and motor rather than social and review empirical data offering preliminary support for this prediction.     

Perceptual similarity in autism

People with autism have consistently been found to outperform controls on visuo-spatial tasks such as block design, embedded figures, and visual search tasks. Plaisted, O'Riordan, and others (Bonnel et al., 2003; O'Riordan & Plaisted, 2001; O'Riordan, Plaisted, Driver, & Baron-Cohen, 2001; Plaisted, O'Riordan, & Baron-Cohen, 1998a, 1998b) have suggested that these findings might be explained in terms of reduced perceptual similarity in autism, and that reduced perceptual similarity could also account for the difficulties that people with autism have in making generalizations to novel situations. In this study, high-functioning adults with autism and ability-matched controls performed a low-level categorization task designed to examine perceptual similarity. Results were analysed using standard statistical techniques and modelled using a quantitative model of categorization. This analysis revealed that participants with autism required reliably longer to learn the category structure than did the control group but, contrary to the predictions of the reduced perceptual similarity hypothesis, no evidence was found of more accurate performance by the participants with autism during the generalization stage. Our results suggest that when all participants are attending to the same attributes of an object in the visual domain, people with autism will not display signs of enhanced perceptual similarity.     

Neural bases of Theory of Mind in children with autism spectrum disorders and children with conduct problems and callous‐unemotional traits

Individuals with autism spectrum disorders (ASD) have difficulty understanding other minds (Theory of Mind; ToM), with atypical processing evident at both behavioural and neural levels. Individuals with conduct problems and high levels of callous‐unemotional (CU) traits (CP/HCU) exhibit reduced responsiveness to others' emotions and difficulties interacting with others, but nonetheless perform normally in experimental tests of ToM. The present study aimed to examine the neural underpinnings of ToM in children (aged 10–16) with ASD (N = 16), CP/HCU (N = 16) and typically developing (TD) controls (N = 16) using a non‐verbal cartoon vignette task. Whilst individuals with ASD were predicted to show reduced fMRI responses across regions involved in ToM processing, CP/HCU individuals were predicted to show no differences compared with TD controls. The analyses indicated that neural responses did not differ between TD and CP/HCU groups during ToM. TD and CP/HCU children exhibited significantly greater medial prefrontal cortex responses during ToM than did the ASD group. Within the ASD group, responses in medial prefrontal cortex and right temporoparietal junction (TPJ) correlated with symptom severity as measured by the Autism Diagnostic Observation Schedule (ADOS). Findings suggest that although both ASD and CP/HCU are characterized by social difficulties, only children with ASD display atypical neural processing associated with ToM.     

自闭症谱系障碍人群词义加工的脑激活模式：基于fMRI研究的元分析

本研究筛选了11项采用功能性磁共振成像技术探究言语自闭症人群词义加工的研究, 探讨了该人群与典型人群脑激活模式的差异是否具有跨研究的稳定性。结果表明, 差异的脑激活模式稳定存在, 且表现为主要涉及左额上回的典型脑区激活不足。该结果为言语ASD人群语言加工的神经机制提供了来自词义加工的跨研究激活证据, 在明确“减弱的额叶激活”这一稳定差异表现的基础上, 强调了针对不同语言加工任务开展元分析研究的必要性。     

ECNN: Enhanced convolutional neural network for efficient diagnosis of autism spectrum disorder

This paper aims to apply deep learning to identify autism spectrum disorder (ASD) patients from a large brain imaging dataset based on the patients’ brain activation patterns. The brain images are collected from the ABIDE (Autism Brain Imaging Data Exchange) database. The proposed convolutional neural network (CNN) architecture investigates functional connectivity patterns between different brain areas to identify specifics patterns to diagnose ASD. The enhanced CNN uses blocks of temporal convolutional layers that employ casual convolutions and dilations; hence, it is suitable for sequential data with temporality large receptive fields. Experimental results show that the proposed ECNN achieves an accuracy of up to 80% accuracy. These patterns show an anticorrelation of brain function between anterior and posterior areas of the brain; that is, the disruption in brain connectivity is one primary evidence of ASD.     

The rubber hand illusion in children with autism spectrum disorders: delayed influence of combined tactile and visual input on proprioception

In the rubber hand illusion, perceived hand ownership can be transferred to a rubber hand after synchronous visual and tactile stimulation. Perceived body ownership and self-other relation are foundational for development of self-awareness, imitation, and empathy, which are all affected in autism spectrum disorders (ASD). We examined the rubber hand illusion in children with and without ASD. Children with ASD were initially less susceptible to the illusion than the comparison group, yet showed the effects of the illusion after 6 minutes. Delayed susceptibility to the illusion may result from atypical multisensory temporal integration and/or an unusually strong reliance on proprioception. Children with ASD who displayed less empathy were significantly less likely to experience the illusion than those with more intact ability to express empathy. A better understanding of body representation in ASD may elucidate neural underpinnings of social deficits, thus informing future intervention approaches.     

More consistent,yet less sensitive: Interval timing in autism spectrum disorders

Even though phenomenological observations and anecdotal reports suggest atypical time processing in individuals with an autism spectrum disorder (ASD), very few psychophysical studies have investigated interval timing, and the obtained results are contradictory. The present study aimed to clarify which timing processes function atypically in ASD and whether they are related to the ASD diagnostic profile. Visual, auditory, and cross-modal interval timing was assessed in 18 individuals with ASD using a repeated standards version of the temporal generalization task. The use of two different standard durations (600 and 1,000 ms) allowed for an assessment of the scalar property of interval timing in ASD, a fundamental characteristic of interval timing. The ASD group showed clearer adherence to the scalar property of interval timing than the control group. In addition, both groups showed the normal effect that auditory stimuli had longer subjective durations than visual ones. Yet, signal detection analysis showed that the sensitivity of temporal discrimination was reduced in the ASD group across modalities, in particular for auditory standards. Moreover, response criteria in the ASD group were related to symptom strength in the communication domain. The findings suggest that temporal intervals are fundamentally processed in the same way in ASD and TD, but with reduced sensitivity for temporal interval differences in ASD. Individuals with ASD may show a more conservative response strategy due to generally decreased sensitivity for the perception of time intervals.     

自闭症谱系障碍个体的疼痛敏感性异常：来自元分析的证据

本研究采用元分析方法, 以疼痛阈限、疼痛诱发生理反应和疼痛评分为结果变量, 考察了自闭症谱系障碍个体(Autism Spectrum Disorder, ASD)的疼痛敏感性异常, 以期为ASD的诊断和干预提供参考。元分析共纳入16项研究(总样本量N = 822)。对于疼痛阈限, ASD组和对照组无显著差异, 但受到疼痛模态等变量的调节作用, 如ASD组的压力疼痛阈限显著低于对照组。对于疼痛诱发生理反应, ASD组对现实医疗疼痛的生理反应强于对照组。然而, ASD组和对照组在疼痛评分上无显著差异。将来研究应结合多模态疼痛刺激和多维度疼痛评估, 系统考察ASD个体的疼痛敏感性及其与临床核心症状之间的联系。