The study compares autistic and non-autistic individuals’ performance on a standard assessment tool called Raven's Standard Progressive Matrices (RSPM). What’s perhaps most interesting about the study is that the autistic subjects performed better than would have been predicted by the results of their IQ tests, and that the autistic subjects, while as accurate as their non-autistic counterparts, performed the test more rapidly. There were also differences in which areas of the brain were active, indicating that the autistic subjects used more visual processing in their reasoning.
Lead author Isabelle Soulières, a post-doctoral fellow at Harvard University who completed the experiment at the Université de Montréal, commented, "Some critics argued that autistics would be unable to complete the RSPM because of its complexity, yet our study shows autistics complete it as efficiently and have a more highly developed perception than non-autistics."
Per the test publisher, “Raven’s SPM is a nonverbal assessment tool designed to measure an individual’s ability to perceive and think clearly, make meaning out of confusion, and formulate new concepts when faced with novel information. It has been used world-wide for more than 70 years.” The article, Enhanced visual processing contributes to matrix reasoning in autism, by Isabelle Soulières, Michelle Dawson, Fabienne Samson, Elise B. Barbeau, Chérif P. Sahyoun, Gary E. Strangman, Thomas A. Zeffiro, Laurent Mottron, was published online on 15 Jun 2009. You can find a review at Autism News or read the abstract for the study online.