Learning effects associated with repeated word-recognition measures using sentence materials

We investigated the learning effects of repeated presentation of sentence materials in an adaptive paradigm in five sessions over 5 to 10 days using 10 subjects in each of three age groups (<30 years, 40 to 60 years, and >65 years). Three target words, based on word-usage frequency and word confusability, were embedded within the seven to nine syllable sentences. Thresholds were obtained for the control lists in Sessions 1 to 5 and for the experimental lists in Sessions 1 and 5. The experimental lists were withdrawn in Sessions 2 to 4. The mean thresholds (1) for the three subject groups were significantly different, (2) for the experimental conditions and the control conditions were not significantly different, and (3) for Session 5 were significantly lower than in Session 1. The implication is that improved thresholds were the result of the subjects learning the test procedure (including the listening-response task, speaker familiarity, and test environment) and not from learning the test words/sentences.