Autistic children's visual sensitivity to face movement

There is a pressing need for studies of large sample sizes and variable age ranges to delineate the mechanism underlying reduced visual attention to biological motion in autism. Here we focused on the basic movement of the eyes or mouth in guiding attention. The stimuli face blinked continuously or moved the mouth silently. In a large sample (145 autistic and 132 non-autistic participants) ranging from 3 to 17 years old, we assessed whether autistic participants showed reduced visual attention to basic movement of the eyes or mouth using a free-viewing eye-tracking task. We found that, like non-autistic participants, autistic participants increased their eye-looking time when viewing the blinking face and increased mouth-looking time when viewing the mouth-moving face. Furthermore, these effects were stable across ages, suggesting the presence of a developmentally stable attentional capture by basic face movements in both groups. We also found that autistic participants looked less at basic face movement than non-autistic participants. Our results suggest that autistic children and adolescents could modulate their visual attention to the basic face movements, but their modulation effect is weaker than non-autistic participants. These results further our understanding of the mechanism underlying visual attention-to-face movement in autistic people.