Abstract
Individuals with autism often perform better on the Embedded Figures Test (EFT) than typically developing individuals. However the underlying skills, used to identify a constituent part of a complex stimulus, are poorly understood. A visual search task was designed which employed a well-studied global shape primitive: radial frequency (RF) patterns. A single RF3 (one with 3 cycles of modulation of the radius in 360°) was easily detected amongst different RF patterns (shallow slope as a function of element set size) consistent with narrow tuning for RF. To approach the EFT, RF patterns were combined into pairs or quads of overlapping RF patterns in the display. Performance declined with increasing overlap. This format was selected to investigate individuals with high and low Autism Quotients (AQ). The high AQ group performed significantly faster on the EFT relative to the low AQ group. Further, the EFT and the increase in reaction time with set size in the singles, pairs and quads conditions was significantly correlated, suggesting the search task measures related skills. In all conditions, the high AQ group was faster detecting the target and significantly less affected by set size in singles, pairs, and quads conditions, relative to low AQ scorers. Thus the search task demonstrated performance differences between these groups, and provides a useful foundation to explore the impact of further manipulations.
This research was partially supported by NH&MRC Project Grant 403942 to M. Maybery, D. Badcock, J. Badcock and E. Pellicano, and ARC Grant no: DP0666206 to D. Badcock