Monday, 06 May 2013

Significance of facial processing in autism re-evaluated

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Autism facesResults were inconsistent with prominent theories that attribute face-processing difficulties in autism to problems with social motivation or attention. Image:Lance Neilson THE idea that those with autism find faces harder to process than other visual stimuli has been challenged in a study by the University of Western Australia.

Research published in the Journal of Experimental Child Psychology, assessed face selectivity and face-processing difficulties in children and adolescents with and without autism.

The team examined discrimination of, and memory for, faces, cars, and inverted faces.

Overall, typically developing children and adolescents without autism performed better than young people with autism.

However, all participants performed significantly worse with identifying pictures of inverted faces compared to upright faces and cars.

Crucially, children and adolescents with autism found cars to be just as difficult to remember as upright faces.

Previous studies have suggested that face perception is selectively, or disproportionately, affected in autism, and this is attributed to reduced social interest and motivation.

Dr Louise Ewing from the ARC Centre of Excellence in Cognition and its Disorders says results were inconsistent with these prominent theories that attribute face-processing difficulties in autism to problems with social motivation or attention.

“Perceptual difficulties in autism extended beyond faces to other complex objects, which challenges the widespread view that faces pose a special perceptual problem for individuals with autism,” Dr Ewing says.

“[In the future] it would be interesting to try and identify the specific mechanisms driving these processing difficulties.”

Forty cognitively able children and adolescents aged 7-15 years were recruited; 29 with an autistic disorder, eight with Asperger syndrome, and three with pervasive developmental disorder—not otherwise specified (PDD-NOS).

Their results were compared to 40 typically developing individuals matched by gender, chronological age, and non-verbal IQ.

Dr Ewing says children and adolescents were selected, because older individuals may have developed strategies to compensate for face processing difficulties.

Participants were given two tasks investigating discrimination and memory ability.

In the Discrimination Task two similar images were morphed together. Participants then had to choose between two morphed images and identify which was “most like” the original.

In the Recognition Memory Task, participants were asked to look at a series of images. They then had to identify if they had seen the face/car/inverted face before when images were shown again in a new position (half angled left/right) along with a set of previously unseen images.

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