Using other minds as a window onto the world: guessing what happened from clues in behaviour.

It has been proposed that mentalising involves retrodicting as well as predicting behaviour, by inferring previous mental states of a target. This study investigated whether retrodiction is impaired in individuals with autism spectrum disorders (ASD). Participants watched videos of real people reacting to the researcher behaving in one of four possible ways. Their task was to decide which of these four "scenarios" each person responded to. Participants' eye movements were recorded. Participants with ASD were poorer than comparison participants at identifying the scenario to which people in the videos were responding. There were no group differences in time spent looking at the eyes or mouth. The findings imply those with ASD are impaired in using mentalising skills for retrodiction.