Abstract
Individuals with autism recurrently demonstrate faster and more accurate performance (cognitive peaks) on the Block Design Task (BDT) subtest of the Wechsler Intelligence Scale. Cognitive accounts suggest that peak BDT performance derives from a reduced "top-down" interference of perceptual cohesiveness of the global figure, whereas perceptual accounts suggest that peaks may originate from superior local visual processing (bottom-up) of component blocks. Using a computerized version of the BDT, the current study assessed whether this characteristic peak originates from a bottom-up perceptual origin by manipulating the visual attributes defining the component blocks of the BDT. Secondly, this study assessed whether there is a relationship in performance difference between manual (traditional) and computerized measures of the BDT. Twenty participants with and without autism completed both traditional and computerized versions of the BDT. For the computerized version, participants were asked to match a centrally presented target design with one of 4 surrounding probes as quickly and accurately as possible, presented on a touch-sensitive screen. The visual attributes of the blocks were manipulated: traditional, red/white; luminance-defined, black/white; or texture-defined blocks. The perceptual coherence of blocks, was also manipulated, where low-coherence (LC) designs necessitated increased local analysis relative to high-coherence (HC) designs. Reaction times in the LC condition were significantly lower in the autism group (i.e., cognitive peak) for the black/white luminance condition only. Correlations between the manual and computerized BDT performance were negative, demonstrating that there is no relationship between performances on these two versions of the test. These results indicate that the characteristic, higher-level visuo-spatial performance in autism, as exemplified by cognitive peaks, may have a perceptual (bottom-up) rather than cognitive (top-down) origin. These results can inform clinical decisions regarding perceptual and cognitive strengths in individuals with autism.
Meeting abstract presented at VSS 2014