Fast-Mapping in Preschoolers with ASD: The Role of Word Learning Constraints, Imitation, and Joint Attention Skills

Background: Fast-mapping is the rapid process by which children learn to link a novel label with a novel referent. Children with typical development (TD) utilize social-cognitive skills (e.g., joint attention, imitation) and word learning constraints (e.g., disambiguation, taxonomic, whole-object) to quickly learn new words. Few studies have investigated word learning in children with autism spectrum disorders (ASD) and the effects that social-cognitive skills may have. It is plausible that children with ASD may be using alternative strategies or skills to learn words due to early symptoms that include language delay and impairments in joint attention and imitation. Objectives: The current study examined the following questions: 1. Do preschoolers with ASD and preschoolers with TD learn words at similar rates? 2. Do preschoolers with ASD utilize word learning constraints to learn new words? 3. What is the relationship between joint attention, imitation, and word learning in preschoolers with ASD? Methods: Participants with ASD were recruited from early intervention preschools. Diagnoses were confirmed using the ADOS-G. Language was assessed by the Mullen Scales of Early Learning. Joint attention skills were assessed by the Early Social Communication Scales and imitation skills were assessed by the Motor Imitation Scale and a verbal imitation measure. Participants with ASD were matched to 2 groups of participants with TD based on chronological age and receptive language. Participants completed 4 word learning conditions: (1) Basic condition examined the ability to link a novel label with a novel object; (2) Disambiguation condition examined the ability to link a novel label with a novel object when it is presented in conjunction with a familiar object; (3) Taxonomic condition examined ability to assume that novel labels extend to objects that are similar in shape; and (4) Whole-Object condition examined ability to assume that novel labels refer to whole objects. All participants completed 4 trials of each word learning condition. Results: Data were collected on 16 children with ASD (mean age = 50 months), 16 children with TD matched on chronological age (mean age = 45 months), and 16 children with TD matched on receptive language raw score from the Mullen. Preliminary analyses show that all 3 groups showed a similar pattern of performance across the word learning conditions. However, children with ASD had significantly lower joint attention and imitation abilities compared to both TD groups. While joint attention and imitation abilities were related to receptive language in the ASD group, these abilities were not related to performance on word learning conditions. Preliminary analyses are ongoing. Conclusions: Preliminary findings indicate that preschoolers with ASD fast-mapped and utilized word learning constraints in a similar manner to children with TD, despite impairments in joint attention and imitation. Thus, the ability to utilize word learning constraints is intact for children with ASD. The current study supports previous research that shows that joint attention is a predictor of language abilities, and also suggests that joint attention and imitation skills may not be necessary prerequisites for vocabulary development in children with ASD.