Comprehension of Word Order in the General Population of Mandarin-Exposed Preschool Children with Autism Spectrum Disorders: Evidence from Intermodal Preferential Looking
Recent comprehension studies have revealed grammatical strengths in children with autism spectrum disorders (ASD), often when they achieve similar vocabulary levels as those of successfully comprehending (but younger) typically developing (TD) children. For example, 3-year-old English speakers with ASD were able to process basic Subject-Verb-Object (SVO) word order similarly to vocabulary-matched 25-month-old TD children (Swensen et al., 2007); 4-5-year-old high-functioning Mandarin-speaking children with autism also used SVO word order in sentence comprehension (Zhou et al., 2017). However, no studies have investigated whether the general population of Mandarin-exposed preschool children with ASD demonstrates similar grammatical strengths.
Using Intermodal Preferential Looking (Naigles & Tovar, 2012), this study assessed the processing of SVO word order in a general group of Mandarin-exposed preschool children with ASD.
Participants included 39 Mandarin-exposed children with ASD (MA=61.28 months (SD=14.84); M(vocabulary)=382.29 words (SD=238.73) and 29 TD children (MA=35.07 months (SD=.92); M(vocabulary)=713.47 words (SD=90.89). The TD children were recruited to be significantly younger (p<.001) with the goal of matching the ASD group in vocabulary; however, TD vocabularies were significantly larger than ASD (p<.001). Children listened to simple reversible SVO sentences paired with two visual scenes, only one of which matched the sentence, e.g., distinguishing between ‘the bird pushing the horse’ and ‘the horse pushing the bird’.
Three different measures of looking behavior while viewing the videos indicated that both groups demonstrated comprehension of SVO order (all tests 1-tailed). With the percent looking to match measure, group effects emerged when the test trials were divided into first-half vs. second-half [F(1,66) = 5.42, p < .05]. Children looked significantly longer to the match during the test relative to control trials for the 1st half (TD) or 2nd half (ASD) of the test trials (ps < .05). With the latency of first look measure, the effect of scene was significant, F(1, 66) = 9.70, p < .01. Both the TD and the ASD groups looked faster to the match than the nonmatch. With the number of switches measure, there were significant effects of trial, F (1, 66) = 40.64, p < .001, and group, F (1,66) = 4.99, p < .05. The number of switches of attention decreased significantly between the control and test trials for both groups (ps < .001).
Mandarin-exposed preschool children with ASD demonstrated similar sensitivity to SVO word order as younger TD children, even though the expressive vocabulary levels of the ASD group were dramatically delayed. Thus regardless of their verbal language skills, grammatical knowledge may be available in the general population of children with ASD. Similar to the comprehension pattern with wh-questions in English-speakers with ASD (Goodwin et al., 2015), the 2nd half of the trials was a more reliable indicator of children with ASD’s comprehension. This may suggest that Mandarin-exposed children with ASD need to hear full rather than fragmentary SVO structures (i.e., without omitted nouns) to master SVO word order, i.e., certain types of input information may be more facilitative than others in the acquisition process of children with ASD.