Dr. Ullman and his colleagues propose that grammar difficulties experienced by children with autism stem from deficits in one of two kinds of memory. Declarative memory, which stores information about facts and events, is used to memorize words and information about those words. Procedural memory, which acquires rules and sequences, is crucial for combining words into complex sequences using grammatical rules. The researchers hypothesize that children with autism have impaired procedural memory, making it difficult for them to learn grammatical rules. However, the children may compensate for this impairment using declarative memory, which may often be relatively unaffected by autism. The researchers plan to construct artificial grammars of syllables, which pilot testing has shown can be learned over the course of a few minutes, allowing the researchers to examine the actual process of grammar acquisition. The researchers will expose children with autism and age-matched healthy controls to syllable strings generated by the grammars. They will then examine how much grammatical knowledge the children have learned and whether the children actually learn the rules or simply memorize specific sets of syllables.