Complex sentence: Autism is a developmental disorder, and Williams believed that life experiences could alter the memory performance in adults who had grown up with autism; he chose to experiment with children separately to see if they had different results from their adult counterparts.
Split into simpler sentences: Autism is a developmental disorder, and Williams believed that life experiences could alter the memory performance in adults who had grown up with autism. He chose to experiment with children separately to see if they had different results from their adult counterparts.