Danielle Ropar

Susceptibility to Illusions and Performance on Visuospatial Tasks in Individuals with Autism

The current study follows a recent paper reporting that individuals with autism were just as susceptible to visual illusions as those without autism (Ropar & Mitchell, 1999). The possibility that individual differences may account for the failure to replicate Happes (1996) findings is explored by presenting a battery of visuospatial tasks thought to measure weak central coherence (embedded figures, block design, Rey complex figure test). Participants with autism were distinguished by relatively good performance on visuospatial tasks, though there was no superiority effect in those with Aspergers syndrome. Performance on the visuospatial battery did not significantly predict susceptibility to illusions in various participant groups, including those with autism and Aspergers syndrome. This suggests that perception of illusions and performance on visuospatial tasks may rely on different mechaisms. The implications for the theory of weak central coherence are discussed.

Do Gaze Cues in Complex Scenes Capture and Direct the Attention of High Functioning Adolescents with ASD? Evidence from Eye-tracking

Visual fixation patterns whilst viewing complex photographic scenes containing one person were studied in 24 high-functioning adolescents with Autism Spectrum Disorders (ASD) and 24 matched typically developing adolescents. Over two different scene presentation durations both groups spent a large, strikingly similar proportion of their viewing time fixating the person’s face. However, time-course analyses revealed differences between groups in priorities of attention to the region of the face containing the eyes. It was also noted that although individuals with ASD were rapidly cued by the gaze direction of the person in the scene, this was not followed by an immediate increase in total fixation duration at the location of gaze, which was the case for typically developing individuals.

How Perception Impacts on Drawings.

In 3 experiments the authors investigate how errors in perception produce errors in drawings. In Experiment 1, when Shepard stimuli were shown as a pair of tables, participants made severe errors in trying to adjust 1 part of the stimulus to match the other. When the table legs were removed, revealing a pair of parallelograms with minimal perspective cues, the illusion was weaker. The authors predicted that participants would err when drawing the table but not the parallelogram stimuli. The results of Experiment 2 support the prediction and establish a direct link between degree of perceptual distortion of the table stimuli and the severity of error in drawing. When drawing only the right-hand part of the figure, participants also erred to a greater degree in drawing the table than the parallelogram (Experiment 3). Collectively, the results suggest that perceptual distortion is linked with errors in drawing the table stimuli.

Children with autism do not overimitate

Copying the behaviour of others is important for forming social bonds with other people and for learning about the world [1]. After seeing an actor demonstrate actions on a novel object, typically developing (TD) children faithfully copy both necessary and visibly unnecessary actions [2]. This ‘overimitation’ is commonly described in terms of learning about the object, but may also reflect a social process such as the child’s motivation to affiliate with the demonstrator [3] or to conform to perceived norms [4]. Previous studies of overimitation do not separate object learning and social imitation because they use novel objects. Even though researchers consider these objects to be causally transparent in their mechanism, young children’s causal reasoning about novel objects is unclear [4]. The present study measures the social component of overimitation by using familiar objects, which preclude the learning component of the task. Here we report a significant reduction in overimitation in children with autism spectrum conditions (ASC). This is coherent with reports that these children have profound difficulties with social engagement [5] and do not spontaneously imitate action style [6] (see also [7]).

Susceptibility to the Shepard illusion in participants with autism: reduced top‐down influences within perception?

Previous research [Ropar & Mitchell, 2002 ] has shown that autistic individuals are somewhat immune to biases induced by top‐down processes, particularly the influence of previous knowledge on perception. In order to test this hypothesis within perception, 18 participants with autism who had measured intelligence in the normal range were compared against 18 matched controls in their susceptibility to the Shepard illusion. The illusion consists in misperceiving the shape of a parallelogram in the presence of depth cues. It is attributed [Mitchell, Ropar, Ackroyd, & Rajendran, 2005 ] to the effect of top‐down constraints within perception. The task involved adjusting a stimulus to the dimensions of a template on a computer screen. Both groups were susceptible to the illusion and the illusion effect was stronger when three‐dimensional perspective cues were prominent. Notably, participants with autism were less susceptible to the illusion than typically developing individuals. The findings raise the possibility that in some instances top‐down influences are attenuated in individuals with autism.

The eye gaze direction of an observed person can bias perception, memory, and attention in adolescents with and without autism spectrum disorder.

The reported experiments aimed to investigate whether a person and his or her gaze direction presented in the context of a naturalistic scene cause perception, memory, and attention to be biased in typically developing adolescents and high-functioning adolescents with autism spectrum disorder (ASD). A novel computerized image manipulation program presented a series of photographic scenes, each containing a person. The program enabled participants to laterally maneuver the scenes behind a static window, the borders of which partially occluded the scenes. The gaze direction of the person in the scenes spontaneously cued attention of both groups in the direction of gaze, affecting judgments of preference (Experiment 1a) and causing memory biases (Experiment 1b). Experiment 2 showed that the gaze direction of a person cues visual search accurately to the exact location of gaze in both groups. These findings suggest that biases in preference, memory, and attention are caused by another persons gaze direction when viewed in a complex scene in adolescents with and without ASD.

A review of visual perspective taking in autism spectrum disorder.

Impairments in social cognition are a key symptom of autism spectrum disorder (ASD). People with autism have great difficulty with understanding the beliefs and desires of other people. In recent years literature has begun to examine the link between impairments in social cognition and abilities which demand the use of spatial and social skills, such as visual perspective taking (VPT). Flavell (1977) defined two levels of perspective taking: VPT level 1 is the ability to understand that other people have a different line of sight to ourselves, whereas VPT level 2 is the understanding that two people viewing the same item from different points in space may see different things. So far, literature on whether either level of VPT is impaired or intact in autism is inconsistent. Here we review studies which have examined VPT levels 1 and 2 in people with autism with a focus on their methods. We conclude the review with an evaluation of the findings into VPT in autism and give recommendations for future research which may give a clearer insight into whether perspective taking is truly impaired in autism.

The Social Modulation of Imitation Fidelity in School-Age Children

Children copy the actions of others with high fidelity, even when they are not causally relevant. This copying of visibly unnecessary actions is termed overimitation. Many competing theories propose mechanisms for overimitation behaviour. The present study examines these theories by studying the social factors that lead children to overimitate actions. Ninety-four children aged 5- to 8-years each completed five trials of an overimitation task. Each trial provided the opportunity to overimitate an action on familiar objects with minimal causal reasoning demands. Social cues (live or video demonstration) and eye contact from the demonstrator were manipulated. After the imitation, childrens ratings of action rationality were collected. Substantial overimitation was seen which increased with age. In older children, overimitation was higher when watching a live demonstrator and when eye contact was absent. Actions rated as irrational were more likely to be imitated than those rated as rational. Children overimitated actions on familiar objects even when they rated those actions as irrational, suggesting that failure of causal reasoning cannot be driving overimitation. Our data support social explanations of overimitation and show that the influence of social factors increases with age over the 5- to 8-year-old age range.

Measuring the value of social engagement in adults with and without autism.

BackgroundDifferences in social communication are commonly reported in autism spectrum condition (ASC). A recent theory attributes this to a reduced motivation to engage with others, that is, deficits in social motivation. However, there are currently few simple, direct, behavioural ways to test this claim. This study uses a new behavioural measure of social motivation to test if preferences for direct gaze and face stimuli are linked to autistic traits or an ASC diagnosis. Our novel choose-a-movie (CAM) paradigm measures the effort participants invest to see particular stimuli. This aspect of social motivation is also known as social seeking.MethodsIn experiment 1, 80 typical adults completed the CAM task and a measure of autistic traits. In experiment 2, 30 adults with ASC and 24 age/IQ-matched typical adults completed the CAM paradigm.ResultsThe results from study one showed that typical adults prefer social stimuli over non-social, but this preference is weaker in those with higher levels of autistic traits. In study two, adults with ASC showed a significant reduction in their preference for direct gaze but little difference in their preference for faces without direct gaze.ConclusionsThese data show that social motivation can be measured in a simple, direct, behavioural paradigm. Furthermore, adults with ASC prefer direct gaze less than typical adults but may not avoid faces without direct gaze. This data advance our understanding of how social motivation may differ between those with and without autism.

Brief Report: How Adolescents with ASD Process Social Information in Complex Scenes. Combining Evidence from Eye Movements and Verbal Descriptions.

We investigated attention, encoding and processing of social aspects of complex photographic scenes. Twenty-four high-functioning adolescents (aged 11–16) with ASD and 24 typically developing matched control participants viewed and then described a series of scenes, each containing a person. Analyses of eye movements and verbal descriptions provided converging evidence that both groups displayed general interest in the person in each scene but the salience of the person was reduced for the ASD participants. Nevertheless, the verbal descriptions revealed that participants with ASD frequently processed the observed person’s emotion or mental state without prompting. They also often mentioned eye-gaze direction, and there was evidence from eye movements and verbal descriptions that gaze was followed accurately. The combination of evidence from eye movements and verbal descriptions provides a rich insight into the way stimuli are processed overall. The merits of using these methods within the same paradigm are discussed.