Using Eye Tracking to Examine Factors Affecting Comprehension In Children with Autism

Background:

Measuring comprehension is a key component of characterizing children’s language skills, but traditional measures may not accurately capture the comprehension skills of young children with autism. It is likely that examiner administered standardized tests underestimate these children’s receptive language skills because of unfamiliarity with the testing environment and limited on-demand responses. Eye tracking paradigms have emerged as a methodology that may more accurately and implicitly measure comprehension in children with autism (Edelson et al., 2008; Swenson et al., 2007; Tek et al., 2008). Importantly, these paradigms provide real-time information and allow for more fine-grained analyses of factors that may influence the speed and accuracy of comprehension, such as age of acquisition, word frequency, and phonotactic probability.

Objectives:

The objectives of this exploratory study were to assess comprehension of familiar nouns in young children with autism using the looking-while-listening paradigm (Fernald et al., 2008) and to explore the effect of age of acquisition on comprehension.

Methods:

A subset of ten children with autism (ages 2-5) who were part of a larger longitudinal project participated in the current study. Children were presented with pairs of pictures of familiar words on a screen with accompanying audio stimuli (e.g., child saw a baby and a ball, and heard, “Where’s the baby? Do you see it?”). Eight words (ball, baby, car, doggie, cup, spoon, shoe, book) were tested twice, for a total of 16 trials. Children’s eye movements were coded frame-by-frame from video by trained coders. A measure of age of acquisition was determined based on the percentage of 8-month-old infants reported to understand each target word in the CDI normative database.   

Results:  

Accuracy and reaction time data were obtained from the majority of participants, meaning that children typically looked at the pictures, not away from the screen. With respect to accuracy, results indicated that the proportion of looking to the target picture increased significantly after the onset of the target word, compared to baseline looking (p<.05). The relationship between reaction time and age of acquisition was non-significant; the Spearman correlation between proportion of looking time to each word and that word’s age of acquisition was .67 (p=.069). This trend toward significance suggests that age of acquisition may relate to comprehension at the preschool age, even for early emerging words.

Conclusions:  

Results suggest that examining the eye movements of preschool children with autism provides a window into their comprehension abilities. Children attended to the task, contributed usable accuracy and reaction time data, and demonstrated comprehension of familiar words. An exploratory analysis suggested that children’s proportion of looking time trended toward an association with the developmental point at which those words are typically understood. Together, these results support the use of the looking-while-listening paradigm to measure comprehension in young children with autism and other populations that are difficult to test. A strength of this paradigm is that it provides a more nuanced picture of real-time comprehension than traditional measures, allowing for further characterization of factors that affect the receptive language abilities of individuals with autism.