Susceptibility to optical illusions varies as a function of the autism-spectrum quotient but not in ways predicted by local–global biases

Individuals with autism spectrum disorder and those with autistic tendencies in non-clinical groups are thought to have a perceptual style privileging local details over global integration. We used 13 illusions to investigate this perceptual style in typically developing adults with various levels of autistic traits. Illusory susceptibility was entered into a principal-component analysis. Only one factor, consisting of the Shepard’s tabletops and Square-diamond illusions, was found to have reduced susceptibility as a function of autistic traits. Given that only two illusions were affected and that these illusions depend mostly on the processing of within-object relational properties, we conclude there is something distinct about autistic-like perceptual functioning but not in ways predicted by a preference of local over global elements

An examination of perseverative errors and cognitive flexibility in autism

Perseveration is a well-replicated finding in autism. The aim of this study was to examine how the context of the task influences performance with respect to this phenomenon. We randomly assigned 137 children aged 6–12 with and without autism to complete a modified card-sorting task under one of two conditions: Children were either told the sorting rules on each trial (Explicit), or were given feedback to formulate the rules themselves (Implicit). While performance was enhanced on the Explicit condition for participants without autism, the participants with autism were disadvantaged by this manipulation. In contrast, there were few differences in performance between groups on the Implicit condition. Exploratory analyses were used to examine this unexpected result; increased autism symptomology was associated with poorer performance

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

Size constancy is preserved but afterimages are prolonged in typical individuals with higher degrees of self-reported autistic traits

Deficits in perceptual constancies from early infancy have been proposed to contribute to autism and exacerbate its symptoms (Hellendoorn et al., Frontiers in Psychology 6:1–16, 2015). Here, we examined size constancy in adults from the general population (N = 106) with different levels of self-reported autistic traits using an approach based on negative afterimages. The afterimage strength, as indexed by duration and vividness, was also quantified. In opposition to the Hellendoorn and colleagues’ model, we were unable to demonstrate any kind of relationship between abilities in size constancy and autistic traits. However, our results demonstrated that individuals with higher degrees of autistic traits experienced more persistent afterimages. We discuss possible retinal and post-retinal explanations for prolonged afterimages in people with higher levels of autistic traits

Orienting of visual attention among persons with autism spectrum disorders : reading versus responding to symbolic cues

Persons with autism spectrum disorders (ASD) appear to be slower to interpret the meaning of symbolic cues. This could be because they are slower to read the symbolic cue, or because they are slower to select a response to the symbolic cue. Groups of participants with autism (n=11), participants with Asperger syndrome (n=9), and typically developing children (n=16) completed four forced-choice reaction time tasks to examine whether persons with ASD are slower to process the symbolic cue or slower to prepare a response to the cue. The participants completed two control conditions and two orienting conditions using non-predictive central arrow cues. In the Target and Cue conditions, participants gave a speeded response to the appearance of either a target (x) or a central arrow. In the Variable Cue Exposure (VCE) condition, the exposure time to the cue varied (100, 300, 600, or 1000 ms) and was followed by a 100 ms blank screen before the presentation of the target. In the Constant Cue Exposure (CCE) condition, all cues were presented for 100 ms and were followed by blank screens that varied in presentation length (100, 300, 600, or 1000 ms) before the presentation of the target. The results indicated that each group showed a unique pattern of responding. In both the Target and Cue conditions, participants with autism were slower than both Asperger syndrome and typically developing children. In both the VCE and CCE conditions, behavioural effects of the cue were found for participants with autism at longer SOAs than for Asperger syndrome, and at longer SOAs for Asperger syndrome than for typically developing children. These findings support the notion that persons with ASDs are impaired in their preparation of responses as opposed to impaired in reading the meaning of the cue. Further, both the ASD groups showed stronger facilitation effects at longer SOAs than typically developing children, indicating that they were less able to use cue predictability to mediate responding. The differences found between autism and Asperger syndrome are discussed in terms of developmental and clinical distinctions between the groups, and implications for theory and research design

Executive function in Down syndrome

Persons with Down syndrome and MA matched typically developing children were tested on two measures each of hot and cool executive function (EF). Tasks were selected to be developmentally appropriate for mental ages between 3 and 6 years. Participants with Down syndrome performed at the same level as verbal mental age (VMA, M = 47.53 months) matched typically developing children on the Children's Gambling Task (Kerr & Zelazo, 2001), a delay of gratification task (Thompson, Barresi, & Moore, 1997) the Dimensional Change Card Sort (DCCS; Frye, Zelazo, & Palfai, 1995), and the Self-Ordered Pointing task (Petrides & Milner, 1982), but showed a disadvantage on the DCCS, a cool EF task, when matched on performance mental age (PMA, M = 58.34 months). These results reflect the complex cognitive profiles of persons with Down syndrome and highlight the need for more precise matching procedures

Eye-Tracking Reveals that the Strength of the Vertical-Horizontal Illusion Increases as the Retinal Image Becomes More Stable with Fixation

The closer a line extends toward a surrounding frame, the longer it appears. This is known as a framing effect. Over 70 years ago, Teodor Künnapas demonstrated that the shape of the visual field itself can act as a frame to influence the perceived length of lines in the vertical-horizontal illusion. This illusion is typically created by having a vertical line rise from the center of a horizontal line of the same length creating an inverted T figure. We aimed to determine if the degree to which one fixates on a spatial location where the two lines bisect could influence the strength of the illusion, assuming that the framing effect would be stronger when the retinal image is more stable. We performed two experiments: the visual-field and vertical-horizontal illusion experiments. The visual-field experiment demonstrated that the participants could discriminate a target more easily when it was presented along the horizontal vs. vertical meridian, confirming a framing influence on visual perception. The vertical-horizontal illusion experiment determined the effects of orientation, size and eye gaze on the strength of the illusion. As predicted, the illusion was strongest when the stimulus was presented in either its standard inverted T orientation or when it was rotated 180° compared to other orientations, and in conditions in which the retinal image was more stable, as indexed by eye tracking. Taken together, we conclude that the results provide support for Teodor Künnapas’ explanation of the vertical-horizontal illusion

3-Year-Olds’ Perseveration on the DCCS Explained: A Meta-Analysis

<p>The Dimensional Change Card Sort (DCCS) task is a widely used measure of preschoolers’ executive function. We combined data for 3,290 3-year-olds from 37 unique studies reporting 130 experimental conditions. Using raw pass/fail counts, we computed the pass rates and chi-squared value for each against chance (50/50) performance. We grouped data according to DCCS variants and computed the standard pass rate and chi-squared and phi for each variant relative to standard. For all standard versions, the mean pass rate was 36%. We compared all other variants to the standard and found robust improvements in performance for manipulations that involved spatial separation of the conflicting dimensions, use of distraction between pre and post-switch, elimination of all conflict, and extra practice. We also found that <i>negative priming</i> offers a better explanation for 3-year-olds’ perseveration than <i>attentional inertia</i>. The results support a theoretical model of 3-year-olds’ performance based on inhibitory control.</p