'Sticky attention' in autistic spectrum disorder--visual psychophysics and movement

We compared children with (n=19, age range 6 - 16 years) and without (n=112) autistic spectrum disorder in a series of visual psychophysical and movement tasks. The tasks provided objective performance measures that tested previous claims based on subjective observations regarding autism. We found that children with autism: (i) were indistinguishable from controls in their form and motion coherence thresholds; (ii) were indistinguishable in their ability to detect subtle changes in realistic dynamic face stimuli; (iii) were indistinguishable in an imitation task requiring tracking a simple rhythmic movement; (iv) showed idiosyncratic differences in a joint attention task. In the joint attention task, targets moved around four corners of a screen during a 90 s video. Three conditions were explored: (i) a technician's head displayed in the middle of the screen (baseline); (ii) the head moved congruently with target position; (iii) the head moved incongruently. The movement execution of the autistic group was indistinguishable from the controls but there were differences in reaction time. The children with autism fell into one of three groups: (i) normal; (ii) slower RT with congruent head movement; (iii) slower RT with incongruent head movement. We suggest that 'sticky attention' in autism can reconcile our laboratory findings with clinical observations.