Individual differences in speech perception under adverse conditions:The role of early perceptual learning

<b>Introduction: </b>Perceptual learning and its generalization to new stimuli enable humans to quickly adapt to large variations in speech encountered in daily life. Previous research has linked rapid adaptation with improved speech recognition in adverse conditions. However, the role of the early, rapid phase of perceptual learning that occurs directly after initial exposure (early perceptual learning) in explaining individual differences in speech perception remains unstudied. <br/><br/><b>Methods:</b> Normal-hearing adults were randomly assigned to report words heard in noise-vocoded, followed by sine-wave English sentences, or vice versa. <br/><br/><b>Results:</b> Early perceptual learning was observed during the first three sentences of each speech distortion, with participants making steep gains in word recognition, before the improvement rate slowed over subsequent sentences. Participants who correctly identified significantly more words during early perceptual learning in the first distortion correctly identified significantly more words overall and showed greater improvement when exposed to the second distortion, indicating that generalization had occurred. <br/><br/><b>Discussion:</b> These findings suggest that early perceptual learning ability may predict individual differences in speech perceptual learning and generalization in challenging listening conditions. However, interpretation is limited by the small sample size, uncontrolled listening environments, and absence of audiometric and cognitive testing.