Two intact executive capacities in children with autism: implications for the core executive dysfunctions in the disorder.

Many studies have shown that children with autism perform at a much lower level than control subjects on tests of executive functioning, defined as tasks requiring subjects to hold information in mind while suppressing a prepotent response. These tasks have invariably required subjects to (a) follow arbitrary and novel rules and (b) make a nonverbal response. We report that when one of these features is absent, children with autism are not impaired relative to controls. They perform at a similar level to normally developing children on the "tubes" task (containing no arbitrary and novel rules) and on the day/night task (in which the output is verbal). Results are consistent, at least, with the hypothesis that children with autism are challenged by executive tasks because they are unlikely to encode rules in a verbal form.