Attention allows us to selectively process the vast amount of information with which we are confronted. By focusing on a certain location or aspect of the visual scene, visual attention enables the prioritization of some aspects of information while ignoring others. Previous research on spatial attention in individuals with autism spectrum disorders (ASD) has produced inconsistent results. Some studies have shown attentional deficits in individuals with ASD, purportedly linked to an inability to adequately control the attention field (i.e., the location and spread of visual spatial attention), whereas others have provided evidence for intact functioning. Many different methods have been used to study attention in ASD, and this diversity of approaches may have contributed to the inconsistencies in previous findings.
The primary aim of this project was to test the hypothesis that high-functioning adults with autism exhibit a deficit in controlling the deployment and size of the endogenous (i.e., voluntary) attention field, by applying psychophysical methods that are now standard in the field of attention research.
In a series of three experiments, we measured the effect of attention on both performance accuracy and reaction times, with and without spatial uncertainty (i.e., lack of predictability concerning the spatial position of the upcoming stimulus). For typically developing individuals, spatial uncertainty increases the size of the attention field. Here, we adopted a spatial uncertainty manipulation to evaluate whether or not this is also the case for individuals with autism. We measured the spatial distribution of performance accuracies and reaction times to quantify the sizes and locations of the attention field, with and without spatial uncertainty, in a group of high-functioning adults with autism (n=9; 20-40 years, 2 female) and a control group matched for age, full score IQ, and verbal IQ (n=9; 20-36 years, 2 female).
We observed consistent results in all three experiments. Experiment 1 provided evidence that endogenous spatial attention increases performance accuracy and decreases reaction time in individuals with autism and that these effects are statistically indistinguishable from those seen in a typically developing matched control group. Experiment 2 verified that these attentional benefits remain, even when the task requires rapid deployment of attention, indicating that individuals with autism are not only capable of allocating endogenous spatial attention, but that they can do so as quickly as control participants can. Finally, in Experiment 3, we found that individuals with autism exhibited slower reaction times overall with spatial uncertainty, but that the effects of attention on performance accuracies and reaction times were indistinguishable between individuals with autism and typically developing individuals.
Voluntary allocation of spatial attention, when measured under tightly controlled experimental conditions, is unaffected in high-functioning adults with autism.
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