Gaze Fixation of Children with and without Autism Spectrum Disorder (ASD) on Human Face Photos

Background: Recent advances in eye-tracking technology have facilitated studies of visual scanning in ASD (Boraston et al, 2007).  Male adolescents and young adults with ASD exhibit an atypical visual scanning pattern focusing on areas other than the eyes (Klin et al,  2002).  However, the development of differences in visual scanning patterns between young children with and without ASD is not yet well understood.

Objectives: Our study aimed to identify whether there was a difference between ASD and typically developing (TD) children in the duration and frequency of gaze fixation on face features.

Methods: 23 children with ASD (3 girls, 8 boys) and without ASD (4 girls, 8 boys) aged 24-64 months (mean age: 37 months) were presented with 20 picture stimuli composed of 12 human headshot photos, 4 puppet headshot photos and 4 object photos.  For eye tracking purposes, the human headshot photos were divided into facial and non-facial regions.  The facial regions were then further subdivided into right eye, left eye, nose, mouth and other regions.

Results: Eye tracking analyses suggested that there was no significant difference between the two groups in both duration and frequency of gaze fixation on the right eye, left eye, and nose.  However, the TD children tended to look at the mouth area significantly more frequently, but not longer, than the ASD ones.  No difference was found in either duration or frequency of gaze fixation on familiar and unfamiliar human headshot photos between the two populations of TD and ASD.

Conclusions: TD children fixated at the mouth area more frequently than those with ASD.  In fact, six-month-old babies who look at their mothers’ mouths were found to have stronger language abilities by 3 years of age (Young et al, in press).  One interpretation may be a difference in IQ; children with TD have better language abilities.