Dyslexia has been linked to timing deficits by previous studies. Here, we investigated specifically two types of implicit temporal adaptation abilities in children with dyslexia, namely the variable foreperiod effect and time-based expectancy. Eighteen children with dyslexia and eighteen typically developing children with ages ranging from 8 to 13 participated. They completed a binary choice reaction time task in which short (1,000 ms) or long (3,000 ms) durations of a visual cue (i.e. foreperiod) predicted with a probability of .9 the direction of a centrally presented arrow. Dyslexic children showed a significantly more pronounced variable foreperiod effect (i.e. responding faster to long foreperiods than to short foreperiods) than normally developing children. However, there were no significant differences between groups in the time-based expectancy effect (i.e. responding differently to likely combinations of foreperiod and target than to unlikely combinations). The results are discussed in the context of time-deficit theories of dyslexia.

Objectives: We studied timed-based expectancy as well as general perceptual-motor speed in children with autism spectrum disorder (ASD). Methods: 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. Results: 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. Conclusion: 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.

Here, we studied the time-based event expectancies in children with Autism spectrum disorder. Nine children with Autism spectrum disorders and ten (6–11 years) typically developing children participated. In a choice-response task with two different pre-target intervals, participants had to indicate the left or right direction of a target stimulus. The target was predicted by the duration of the pre-target interval with 80% validity. We found that, in children with Autism spectrum disorder, in contrast to typically developing children, the formation of time-based event expectancies was restricted to the relatively longer pre-target interval. This pattern is rather typical for healthy young adults. These findings indicate that children with Autism spectrum disorder are able to form time-based event expectancies, and that, similar to healthy young adults, longer pre-target intervals enable them to make more optimal temporal predictions.