International Meeting for Autism Research: Object-Directed Exploratory Behavior in Toddlers with ASD, DD, and TD

Object-Directed Exploratory Behavior in Toddlers with ASD, DD, and TD

Friday, May 21, 2010: 10:30 AM
Grand Ballroom CD Level 5 (Philadelphia Marriott Downtown)
9:45 AM
S. Macari , Child Study Center, Yale University School of Medicine, New Haven, CT
K. Chawarska , Child Study Center, Yale University School of Medicine, New Haven, CT
Background: Toddlers with ASD explore their world differently than toddlers with developmental delays (DD) or typical development (TD). Both infant home video studies and prospective studies have documented behavioral differences as early as 12 months of age in infants with ASD compared with DD and TD infants in such domains as visual and manual exploration of objects.   
Objectives: While exploration of the social environment has been extensively studied in young children with ASD, less is known about their patterns of object exploration.  This area is particularly important considering the amount of time that they devote to exploring their physical environment. Here we examine whether there are specific features of object exploration that differentiate toddlers with ASD from their DD and TD counterparts.  
Methods: Object exploration was examined during a standardized 10-minute toy play session in 21 toddlers with ASD (age: M=21 months, SD=3.0), 25 toddlers with TD (age:  M=18 months, SD=3.8), and 8 toddlers with DD (age: M=20 months, SD=4.5). The toys afforded a range of sensorimotor exploratory behaviors. ASD and DD groups were matched on nonverbal DQ.  Behavior was coded blind to the hypotheses of the study and to group membership.
Results: Compared to toddlers with DD and TD, toddlers with ASD engaged in more manual rotation of objects (F(2,52)=7.8, p<.001) and prolonged gaze to objects (bouts longer than 10 seconds) (F(2,52)=6.1, p<.01). Furthermore, they made less eye contact with adults during play (F(2,52)=13.0, p<.001) than both control groups and showed objects less frequently than TD toddlers (F(2,52)=5.5, p<.01). Toddlers with DD banged objects more frequently than the other toddlers (F(2,52)=4.4, p<.05).  
A discriminant function analysis was performed to find the most parsimonious profile of object-directed behaviors that best predicted group membership.  Two significant functions emerged that differentiated the three groups, Λ = .38, χ2(16) = 45.6, p<.001.  The first function separated the ASD group from the other groups with rotating objects and prolonged gaze having the highest loadings. The second function separated the DD group from the other groups with banging objects loading highest. Together, the two functions correctly classified 76% of toddlers with ASD, 75% of toddlers with DD and 80% of TD toddlers.  Simultaneous consideration of spontaneously initiated eye contact and showing in addition to the exploratory behaviors led to correct classification of 95% of toddlers with ASD and 88% of non-ASD toddlers.
Conclusions: In the second year, toddlers with ASD exhibit a profile of object exploration that differentiates them from TD toddlers and toddlers with DD. They tend to rotate toys more frequently and examine toys visually for prolonged periods of time. Toddlers with DD engaged in banging objects more than toddlers in the other groups. These three behaviors (rotating, prolonged gaze, and banging) classified toddlers into three groups with a relatively high level of accuracy.  Consideration of adult-directed social behaviors (eye contact, showing) further improved the fit of the model.  These results suggest that characteristics of object exploration during a brief solitary play session can serve as red flags and aid the diagnostic process.
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