Kate Plaisted

Recognition of faux pas by normally developing children and children with Asperger syndrome or high-functioning autism.

Most theory of mind (ToM) tests are designed for subjects with a mental age of 4–6 years. There are very few ToM tests for subjects who are older or more able than this. We report a new test of ToM, designed for children 7–11 years old. The task involves recognizing faux pas. Study 1 tested 7–9, and 11-year-old normal children. Results showed that the ability to detect faux pas developed with age and that there was a differential developmental profile between the two sexes (female superiority). Study 2 tested children with Asperger syndrome (AS) or high-functioning autism (HFA), selected for being able to pass traditional 4- to 6-year level (first- and second-order) false belief tests. Results showed that whereas normal 9- to 11-year-old children were skilled at detecting faux pas, children with AS or HFA were impaired on this task. Study 3 reports a refinement in the test, employing control stimuli. This replicated the results from Study 2. Some patients with AS or HFA were able to recognize faux pas but still produced them. Future research should assess faux pas production.

Superior visual search in autism.

Children with a diagnosis of autism and normally developing children, matched for age and general ability, were tested on a series of visual search tasks in 2 separate experiments. The children with autism performed better than the normally developing children on difficult visual search tasks. This result occurred regardless of whether the target was uniquely defined by a single feature or a conjunction of features, as long as ceiling effects did not mask the difference. Superior visual search performance in autism can be seen as analogous to other reports of enhanced unique item detection in autism. Unique item detection in autism is discussed in the light of mechanisms proposed to be involved in normal visual search performance.

Children with Autism Show Local Precedence in a Divided Attention Task and Global Precedence in a Selective Attention Task

Children with a diagnosis of autism and typically developing children were given two variations of the Navon task (Navon, 1977), which required responding to a target that could appear at the global level, the local level, or both levels. In one variation, the divided attention task, no information was given to children regarding the level at which a target would appear on any one trial. In the other, the selective attention task, children were instructed to attend to either the local or the global level. Typically developing children made most errors when the target appeared at the local level whereas children with autism made more errors when the target appeared at the global level in the divided attention task. Both groups of children were quicker to respond to the global target than the local target in the selective attention task. The presence of normal global processing in the children with autism in one task but not in the other is discussed in terms of a deficit in mechanisms that inhibit local information in the absence of overt priming or voluntary selective attention to local information.

High motion coherence thresholds in children with autism.

BACKGROUND We assessed motion processing in a group of high functioning children with autism and a group of typically developing children, using a coherent motion detection task. METHOD Twenty-five children with autism (mean age 11 years, 8 months) and 22 typically developing children matched for non-verbal mental ability and chronological age were required to detect the direction of moving dots in a random dot kinematogram. RESULTS The group of children with autism showed significantly higher motion coherence thresholds than the typically developing children (i.e., they showed an impaired ability to detect coherent motion). CONCLUSIONS This finding suggests that some individuals with autism may show impairments in low-level visual processing--specifically in the magnocellular visual pathway. The findings are discussed in terms of implications for higher-level cognitive theories of autism, and the suggestion is made that more work needs to be carried out to further investigate low-level visual processing in autism.

Enhanced Visual Search for a Conjunctive Target in Autism: A Research Note

Children with and without autism were compared on two visual search tasks in which a letter target appeared among two sets of letter distracters. In one task, the target shared colour with one set of distracters but was unique in shape--the feature search task. In the other, the conjunctive search task, the target shared colour with one set and shape with another set of distracters. Although search was slower in the conjunctive task than the feature task in normally developing control children, children with autism showed no significant slowing in reaction time in the conjunctive task and were faster than control children in this task. This result is discussed in the light of theories of visual search which state that rate of search is determined by the degree of similarity between target and distracters.

Enhanced Discrimination of Novel, Highly Similar Stimuli by Adults with Autism During a Perceptual Learning Task

High-functioning adults with autism and control adults were tested on a perceptual learning task that compared discrimination performance on familiar and novel stimuli. Control adults were better able to discriminate familiar than novel stimuli--the perceptual learning effect. No perceptual learning effect was observed in adults with autism although they discriminated the novel stimuli significantly better than control adults. This enhanced discrimination learning about novel, but not familiar, stimuli in autism is discussed in relation to two current hypotheses of information processing in autism--weak central coherence and reduced attention-switching--and a new third hypothesis, which suggests that features held in common between stimuli are processed poorly and features unique to a stimulus are processed well in autism.

Top-Down Attentional Modulation in Autistic Spectrum Disorders Is Stimulus-Specific

This study investigated top-down modulation of bottom-up attentional capture in children with autistic spectrum disorders (ASDs) and in a typically developing (TD) comparison group using a spatial-cuing task (Experiment 1) and a series of visual search tasks (Experiment 2) employing task-irrelevant distractors. The effect of color and onset singleton distractors was investigated. The TD group showed similar top-down modulation of color and onset stimuli. The ASD group showed typical top-down modulation of color stimuli, but impaired top-down modulation of onset stimuli. The results suggest that children with ASDs may be impaired at prioritizing dynamic stimuli; this has implications for social processing impairments in ASDs.

Autism: Not Interested or Not ‘Tuned-in’?

Recent studies of perceptual adaptation to faces have revolutionised our understanding of neural mechanisms that support face recognition. A new study has applied this approach to autistic spectrum disorders, revealing severe deficits in such adaptation.