Visual Processing of the Faces of Humans and Dogs by Children with Autism Spectrum Disorder: An Eye-Tracking Study

Recent studies indicate a positive correlation between canine-assisted interventions and social and communicative abilities in people with autism. These benefits could be due to more efficient processing of socially informative areas when dog faces are processed. Using an eye tracker, this study aimed to assess the visual processing of faces in 13 children with autism spectrum disorder (ASD) and 13 neurotypical (NT) children when gazing at the faces of humans and of dogs. We divided the faces into two categories. First, individual faces of adult humans, children, and dogs were used in a free-viewing paradigm, where the area of interest was the eyes. We recorded the total time spent gazing at the eyes (dwell time), latency to the first look, and continuous gaze time. Second, pairs of faces were presented at the same time in a pair paradigm, and preferences in terms of face position (left/right) and type (dog/human), and the number of transitions between faces, were measured. When presented with pairs of faces, ASD children gazed for longer at the dog's face, regardless of its position, and showed a higher number of shifts between pictures when the face of a dog was present. However, the NT group did not discriminate between the two faces. The results for individual faces showed significant differences in how ASD children look at the eyes of faces rather than differences in the total duration of the gaze; they are faster in terms of their first gaze and exhibit a longer average fixation time when gazing at the eyes of dogs compared with those of humans. Both human and dog faces were processed atypically in children with ASD, who seemed to engage with dogs more rapidly and for extended periods. This suggests possible socio-communicative benefits of human-dog interactions for people with autism, from a visual processing point of view.