Small Sets of Novel Words Are Fully Retained After 1-Week in Typically Developing Children and Down Syndrome: A Fast Mapping Study

Abstract

Objective Down syndrome (DS) is a population with known hippocampal impairment, with studies showing that individuals with DS display difficulties in spatial navigation and remembering arbitrary bindings. Recent research has also demonstrated the importance of the hippocampus for novel word learning. Based on these data, we aimed to determine whether individuals with DS show deficits in learning new labels and if they may benefit from encoding conditions thought to be less reliant on hippocampal function (i.e., through fast mapping). Method In the current study, we examine immediate, 5-minute, and 1-week delayed word-learning across two learning conditions (e.g., explicit encoding vs. fast mapping). These conditions were examined across group (twenty-six 3–5 year old typically developing children and twenty-six 11–28 year old individuals with DS with comparable verbal and nonverbal scores on the Kaufman Brief Intelligence Test – second edition) and in reference to sleep quality. Results Both individuals with and without DS showed retention after a 1-week delay, and the current study found no benefit of the fast mapping condition in either group contrary to our expectations. Eye tracking data showed that preferential eye movements to target words were not present immediately but emerged after 1-week in both groups. Further, sleep measures collected via actigraphy did not relate to retention in either group. Conclusion This study presents novel data on long-term knowledge retention in reference to sleep patterns in DS and adds to a body of knowledge helping us to understand the processes of word learning in typical and atypically developing populations.

The influence of sleep on language production modalities in preschool children with Down syndrome

“…(2018) reported that daytime naps decrease word retention in children with DS, contrary to the growing evidence that suggests that daytime naps are beneficial in children with TD (Horváth et al., 2015). Sakhon, Edwards, Luongo, Murphy, and Edgin (2018) failed to find a relationship between sleep and fast mapping skills in adolescents and adults with DS when a small set of repeated mappings were tested over a period of 1 week.…”

Referent selection in children with Autism Spectrum Condition and intellectual disabilities: Do social cues affect word-to-object or word-to-location mappings?

“…In terms of fast mapping, children with ID form a word-picture mapping following initial object exposure, although they are impaired relative to a TD group remembering the object name when faced with distractor objects or labels (Wilkinson, 2007) Children with Down Syndrome even retain novel words after a one-week delay (Sakhon, Edwards, Luongo, Murphy & Edgin, 2018). Taken together, this suggests that children with ID without ASC may show better fast mapping ability than those with ASC.…”

Adult Fast-Mapping Memory Research Is Based on a Misinterpretation of Developmental-Word-Learning Data

“…In research in which children’s retention in fast-mapping conditions has been directly compared with conditions explicitly giving the word–object mappings, there is no evidence that fast-mapping conditions specifically help children to learn those words (Jaswal & Markman, 2003; Zosh, Brinster, & Halberda, 2013). 1 Indeed, even in studies with developmental populations associated with compromised hippocampus functions (e.g., Down’s Syndrome), fast-mapping conditions do not give rise to better learning than explicit-instruction conditions (Sakhon, Edwards, Luongo, Murphy, & Edgin, 2018).…”

“…For example, although two early studies found that patients with damage to the hippocampus learn new words under fast-mapping but not explicit-encoding conditions (Merhav, Karni, & Gilboa, 2014; Sharon et al, 2011), this finding has not been readily replicated with similar patient groups (Smith, Urgolites, Hopkins, & Squire, 2014; Warren & Duff, 2014; Warren, Tranel, & Duff, 2016). Furthermore, a number of studies with participant populations associated with compromised hippocampal function have failed to find any difference in word learning between explicit-encoding and fast-mapping conditions relative to control conditions (Greve, Cooper, & Henson, 2014; Korenic et al, 2016; Sakhon et al, 2018). Finally, brain-imaging studies with healthy adults have found the hippocampus to be active during both fast-mapping encoding and retrieval (Atir-Sharon et al, 2015; Merhav et al, 2015).…”