Auditory Processing Difficulties Influence on Perceptual Learning

Understanding spoken speech is a complex process that comes to most people easily, yet past research demonstrates that some people face difficulties with auditory processing. Listeners adjust to variations in speech by integrating auditory, visual, and other cues. However, people who have difficulties processing auditory information often rely less on visual cues, such as lip-reading. We investigated how listeners' reported difficulties in perceiving auditory information interact with their use of visual cues. This was a replication and extension of a study by Kraljic, Samuel, and Brennan (2008). Participants were divided into four groups based on which phoneme was changed (?S signifying [s] or ?SH signifying [∫]) and if listeners viewed the pen-in-hand (Characteristic) or the pen-in-mouth (Incidental) version of these words. The participants’ boundaries of these two phonemes were established in the category-identification task, in which participants categorized ambiguous sounds on the “SH” - “S” continuum as being more S-like or SH-like. We measured participants' perceptual learning—the way people restructure their phonemic boundaries to better understand speakers' variation—based on their categorization of the ambiguous sounds. After completing these tasks, participants responded to questions regarding their language background, and their auditory processing difficulties in daily experience. We did not replicate the findings of Kraljic and colleagues (2008), as we did not find an effect of visual context on perceptual learning. Contrary to our predictions, we also did not find an effect of individual differences in auditory processing on perceptual learning and no interaction with visual context. Given that the effect of visual context has been replicated before, our results are inconclusive. Individual differences' effect on perceptual learning should be explored further to gain insight into what affects perceptual learning and how to improve speech perception for those with difficulties.