Object-Selection Processes In Infant Siblings: Differences Between Typical and Atypical Development

Background: Play and self-guided object exploration are fundamental activities throughout development. Through their own actions, children learn about objects, physical properties, their own skills and abilities (Needham & Libertus, 2010). At the same time, manual-exploration behaviors offer unique clinical observation opportunities to detect repetitive behaviors, sensory interests, and use of functional play. Atypical exploration choices or patterns may be predictive of developmental disorders or delays. 

Objectives:  To investigate play and object-exploration behavior in a prospective study of infants at-risk for autism.

Methods:  Participants were fifteen 6-month-olds, nineteen 10-month-olds, twenty-three 14-month-olds, and twenty 18-month-old infants who had an older sibling with autism. Based on clinical impressions (including administration of Mullen Scales of Early Learning and ADOS) 39 infants were classified as “No Concern” and 38 were classified as “Autism Suspected”. Object exploration was assessed during 3 minutes of independent engagement with three toys (6-month-olds: nubby ball; slinky; teething toy) or three sets of toys (10-18-month-olds: shape sorter; slinky and net pair; nesting cars). A computer-based coding method was used to score exploration of each object/set during the first, second, and third minute of the assessment.

Results:  A repeated measures ANOVA on the number of gaze-shifts from object to adult with Toy (3) as within-subject factor and Age (4) and Concern (2) as between-subject factors revealed a significant Toy x Concern interaction (F(2, 68) = 4.58, p < .02). Separate analyses for each toy/set revealed more gaze-shifts in the “No Concern” compared to the “Autism Suspected” group for the slinky toy (F(1,75) = 7.35, p < .01). Therefore, subsequent analyses focused on simultaneous manual-visual exploration of the slinky toy only. Separate ANOVAs for the 1^st, 2^nd, and 3^rd minute of exploration revealed significantly more manual-visual exploration of the slinky toy during the 1^st minute of exploration in the “No Concern” compared to the “Autism Suspected” group (F(1,75) = 7.52, p < .01).

Conclusions:  Our results show surprising differences in toy exploration and preferences between infant siblings in whom autism was suspected and infant siblings about whom there was no clinical concern. Compared to infants who were suspected to develop autism during clinical evaluations, infants who raised no concerns for autism showed relatively more exploration of the slinky toy and more social referencing during engagement with this toy. Our results suggest that different object properties may guide initial object selection and engagement in typical and atypical development. Typically developing infants may consider factors such as novelty, affordances, or visual appeal when selecting a toy for closer exploration. Of the toys used here, the slinky toy was relatively novel for infants, easy to grasp and manipulate with one hand, brightly colored, and offered interesting affordances (e.g., pulling, banging). Infants in the “Autism Suspected” group seemed to have weighted these factors differently or less consistently than infants in the “No Concern” group when making their initial toy selection. Which objects are chosen for closer exploration has implications on the possible actions available to the infant, the visual-tactile simulation experienced, and may influence developmental trajectories.