Reduced Looking at Imitative Actions in Young Children with ASD

Background:

Imitation is a fundamental component of social behaviour, and noted from early stages of human development. Atypical imitation has been reported in ASD in clinical and observational accounts. One hypothesis suggests that imitation serves to build social rapport due to its inherently rewarding nature. The rewarding nature of imitation is noted from neuroimaging evidence that shows increased activity in reward-related neural regions when participants are being imitated, or watching imitative vs non-imitative interactions (Kuhn et al., 2010; Kuhn et al., 2011). A recent study using eye-tracking and self-report demonstrated that individuals with low trait empathy showed a reduced reward value for imitation (Neufeld & Chakrabarti, 2016). These lines of evidence lead to the question of whether imitation carries a similar reward value for children with and without ASD. Reduced reward value for imitation might manifest in reduced attention to imitative actions, which in turn can have long-term consequences, since many essential skills including language and social learning relies on and benefits from imitative actions.

Objectives:

To test, using an eye-tracking experiment, whether children with and without ASD attend equivalently to videos of naturalistic imitative play.

Methods:

Fifty-one children (22 ASD, 29 typically developing children (TD), aged 29-93 months (ASD mean=57.5, SD=17.5; TD mean=60.2, SD=8.1) were enrolled in the study. TD children were recruited in two mainstream nursery schools in Messina, Italy. ASD children were tested at the clinical facilities within the National Research Council of Italy (CNR), Messina. The Autism Diagnostic Observation Schedule - Second Edition (ADOS-2) and the Griffith’s Mental Development Scale (GMDS) were used as part of the diagnostic assessment.

The experiment consisted of 6 trials (4 toy activity videos, and 2 gross motor imitation activity videos) of a child and an adult imitating each other (4 actions each video) in a naturalistic play interaction, presented on a computer screen. Each trial lasted 25 seconds and was presented in a random order. Gaze patterns were recorded with a SMI iView XTM RED dark-pupil 120Hz eye-tracking system (Sensomotoric Instruments, 2005) and exported using SMI BeGaze 2.4 software. Statistical analyses were conducted using R (http://www.r-project.org/). A linear mixed effects model (package: lme4) was applied to explore the effect of group, gender and age to predict looking time (dwell time), accounting for the random effects of the different trials and the different regions of interest (adult and child activity, adult and child face, background). Results:

A main effect of group was observed on the looking time to imitative actions (Wald chi square= 6.1, p = .01), lowering it by about 1.15 sec(SE=0.45 sec) in the ASD group. No significant effect of age and gender was found (Wald chi square= 0.99, p = 0.3 and Wald chi square= 1.6, p = 0.2 respectively).

Conclusions:

We found a significant group difference in the amount of time spent attending to the imitative activities, with the ASD children attending less than the TD children to the videos. This provides preliminary evidence of a reduced reward value for imitative actions in ASD.