Perceptual Dissimilarity and Cognitive Performance Predict Novel Word Retention, but Not Extension Skills in Down Syndrome

While the influence of cognitive and linguistic capacities and the perceptual features of objects on word-learning skills in people with typical development (TD) are well understood, there is little evidence concerning these mechanisms in people with Down syndrome (DS). Using an eye-tracking task, this study examined the ability of 29 children with DS (mean mental age: 3.44 years) to identify familiar words, fast-map pseudowords to novel objects, retain word-object mappings, and extend these mappings to new objects of similar shape. It also contrasted their word-learning abilities to those of 26 two-to-five-year-olds with TD and examined how cognitive and linguistic skills and perceptual information influenced those abilities. Children with DS were found to have similar identification, fast-mapping, and extension skills as their peers with TD, but retained fewer word-object mappings. Greater retention skills are related to mental age, oral vocabulary, and greater perceptual differences between the target and surrounding objects.