| The present study was designed to examine the spatial extent and flexibility of the attentional spotlight in autism. For this purpose, a simple visual orienting paradigm was used. Participants were required to identify a target appearing in one of eight locations positioned around a central fixation cross. Prior to target presentation, exogenous cues were used to orient attention either validly or invalidly to the target location. The cue size and the distance between cue and target were manipulated in order to examine the size of the attentional spotlight and its ability to adjust to task demands. Participants included 23 adolescents and adults with autism, 23 typically developing individuals, and 18 individuals with moderate to severe traumatic brain injury (TBI). It was hypothesized that the individuals with autism would demonstrate a spatially narrow, inflexible attentional spotlight in comparison to age-matched typical controls and ability-matched individuals with TBI. The group with TBI was expected to show evidence of a broader, less efficient attentional beam compared to typical controls.; As predicted, the individuals with autism showed abnormally strong enhancement of sensory stimulation at the selected focus and abnormally weak enhancement in surrounding locations, indicating a narrow attentional spotlight. In contrast, the typical individuals were able to adjust their attentional spotlight according to task demands, and the individuals with TBI showed evidence of a broader attentional beam with more diffuse enhancement across the beam compared to typical controls. None of the attentional effects observed in autism were related to developmental level, suggesting that the attentional effects are related to autism rather than developmental disability. In contrast, the attentional effects in TBI were related to developmental level, as would be expected following an acquired brain injury. The findings provide support for the claim of a narrow, more concentrated attentional focus and difficulty orienting to peripheral stimuli in autism. Both the theoretical and clinical implications of these findings are discussed, as are future directions for research on visual orienting in autism and other disorders of development. |
