Learning from Exploration: Manual Exploration Strategies in Infants with and without ASD

Background: Object exploration skills are critical for learning about the physical and social world. A growing number of studies suggest that infants’ motor and exploration skills may influence development across domains, including perceptual and social-cognitive development (e.g., Libertus & Needham, 2010, 2011; Soska, Adolph, & Johnson, 2010). Further, atypical or delayed motor skills are commonly observed in children and adults with Autism Spectrum Disorders (ASD) and may manifest early in development (Bhat, Landa, & Galloway, 2011). Infants at high risk for ASD have been reported to show delayed postural control and gross motor skills (Flanagan, Landa, Bhat, & Bauman, 2012; Nickel, Thatcher, Keller, Wozniak, & Iverson, 2013). Early motor delays may affect object exploration strategies in infants later diagnosed with ASD and interfere with their learning about the physical and social world.

Objectives: Characterize manual exploration strategies in infants later diagnosed with ASD to inform understanding of developmental etiology and early intervention approaches.

Methods: Manual exploration strategies are observed in a total of 50 infants (20 low-risk (LR) infants without ASD, 20 high-risk (HR) infants without ASD, and 10 infants diagnosed with ASD at age 36 months). As part of a larger longitudinal study, infants were videotaped at home for 45 min at six and ten months of age. Manual exploration analyses focus on infants’ behavior during a 1 min object exploration task using a toy rattle.

Results: Proportions of time infants engaged in active mouthing (out of all mouthing), one-handed exploration, and object shaking (out of all touching) were analyzed. Analyses to date indicate that at age six months, ASD infants show less active mouthing behavior than LR infants (M_ASD = 46.91%, M_LR = 80.57%), but more one-handed exploration (M_ASD = 62.30%, M_LR = 36.19%,). High-risk infants without ASD fall in-between the LR and ASD groups on both measures (M_Mouthing = 56.08%, M_One-hand = 45.82%). By age ten months, LR infants increase their functional exploration of the toy rattle by showing more shaking behavior (M_6m = 14.27%; M_10m = 24.39%). In contrast, ASD infants show no such increase from six to ten months of age (M_6m = 16.33%; M_10m = 14.46%). High-risk infants without ASD show a small increase in shaking over the same time-period (M_6m = 11.23%; M_10m = 17.32%).

Conclusions: Object exploration strategies differ between infants subsequently diagnosed with ASD and typically developing infants. Infants later diagnosed with ASD seem to provide themselves with fewer opportunities to learn about critical object features such as texture or function by engaging less in active mouthing and shaking behaviors. Further, one-handed grasping preferences may be counterproductive and hinder overall grasping success in infancy. In agreement with recent findings (Nickel et al., 2013), one-handed grasping also suggest relative postural instability in infants later diagnosed with ASD as the second hand might be needed to stabilize the body during exploration. These preliminary results indicate that early fine motor skills should be closely observed in infants at high genetic risk for ASD and that motor training should be included in early intervention approaches.