The children with autism avoided looking at mouths in the videos
The researchers found that neurotypical children were better at identifying the synchronized video, and preferred to watch that one instead of the video with the audio delay.
This was identifiable with 0.6 or 1 second delays, but there was no preference found for the minor 0.3 second delay.
The children with autism spectrum disorder paid equal attention to the synchronized video as they did to the video with an audio delay. This turned out to be not very much attention, as they also looked away from the screen more frequently than did the neurotypical children.
Also, when the children with autism were looking at the face, they typically avoided looking at the mouth. While eye movement is important to non-verbal communication, mouth movement is even more important, especially when identifying which video has audio that matches with the visuals.