Children with autism spectrum disorder show increased sensitivity to time-based predictability.

We studied timed-based expectancy as well as general perceptual-motor speed in children with autism spectrum disorder (ASD). In Experiment 1, 11 children with ASD and 11 typically developing children (TD) (6-13 years) completed a binary choice response task in which foreperiod duration predicted the response target's location with a probability of 0.8. In Experiment 2, we compared performance between 10 children with ASD (6-11 years) and 10 TD children by using a simple reaction time test. Employing a binary forced choice task where the duration of a pre-target interval (800 or 1400 ms) probabilistically predicted the target, we found that children with ASD were sensitive to the temporal regularity, whereas TD children were not. Children with ASD were faster for expected combinations of interval and target location but they were also less accurate for those combinations. Results from an additional simple reaction time test indicate that the development of general perceptual-motor processes was delayed in children with ASD. However, the ability for children with ASD to form time-based expectancies was not correlated with their performance in the simple reaction time test. Children with ASD show significantly greater sensitivity towards time-based predictability than TD children. However, the development of general perceptual-motor processes was impaired in children with ASD.