It seems to me that the autistic study subjects actually performed better than the neurotypical controls in the pre and post-test phases of learning a complex social task in this study, but neverthless, because differences could be discerned in the functioning and structure of the autistics' brains, this is interpreted as evidence of some problem in the autistic brain that impairs learning. It seems to me that time and time again, reports of research on autism demonstrate that the problem with being autistic is much more about being different than with being incapable.
Sarah E. Schipul, Diane L. Williams, Timothy A. Keller, Nancy J. Minshew, and Marcel Adam Just (2011) Distinctive neural processes during learning in autism. Cerebral Cortex. in press.