Behavioral variability is not unique to those with ASD (Castellanos et al., 2005), therefore future research is required to establish the universality of increased EEG variability in ASD and in other developmental disorders (such as ADHD), and to establish whether increased variability is a general characteristic of brain pathology, or whether distinctive features of variability occur in different developmental disorders. Furthermore it is necessary to establish the extent to which increased EEG variability is an enduring endophenotype of ASD, or whether it related either to external factors such as context or particular task requirements, or to internal factors such as cognitive state (e.g., awake, asleep, tired, alert). The presence of a significant correlation between EEG variability and response time variability provides preliminary evidence that response time variability and EEG variability are related, albeit in a small sample of participants. This relationship should be tested more rigorously in future studies in which larger groups of participants are tested and different types of behavioral response tasks (such as simple reaction time, choice reaction time, response inhibition, etc.) are performed. In addition, more
