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For many years, scholars have noted that long-term retention improves significantly when learners frequently test themselves on the new material rather than engage in continuous study with no intermittent testing. This longstanding observation has recently been the subject of a resurgence in research. In this presentation, I will discuss a collaborative project in which we apply concepts of repeated testing (retrieval) to the study of novel word learning by preschoolers with developmental language disorder (DLD) and their peers with typical language development. Each of the experiments reported involved a within-subjects design in which half of the novel words were presented in a repeated-retrieval condition hypothesized to facilitate long-term retention and the other half of the words were presented in a comparison condition that approximated traditional procedures. Children were presented with both the novel words themselves (word forms) as well their arbitrary definitions (meanings). Testing occurred immediately after the learning period and one week later. Testing involved word form and meaning recall, recognition (picture identification), and neural responses (N400 event-related brain potentials) on a match-mismatch task. Children showed enhanced recall for novel words that were taught in the repeated retrieval conditions. Furthermore, larger N400s were elicited for mismatches involving words in the repeated retrieval conditions than for those involving words in the comparison conditions, indicating that priming for lexical access was stronger when children learned the novel words with repeated retrieval. Although the children with DLD appeared to have weaker initial encoding than their peers, they benefited as much from repeated retrieval as their peers and were indistinguishable from peers in their ability to retain information from immediate testing to testing one week later. We are pursuing additional studies along these lines, for the findings have important implications: Along with advocating for children hearing many words in their input, we might have reason to encourage child-friendly activities that encourage the children to practice retrieving the words they recently heard. This work was supported by NIH-NIDCD R01 DC014708 and NIH-NIDCD T32 DC00030. |
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