Auditory-semantic distraction : a process-oriented approach.

The present thesis examined whether the interference-by-process construct, as applied to auditory distraction during visual-verbal serial recall (the irrelevant sound effect, ISE), also holds as a useful framework for interpreting auditory-semantic distraction whereby performance on tasks requiring semantic focal processes is disrupted by the semantic properties of irrelevant sound. To address this goal, several semantic focal tasks were used in conjunction with manipulations of task-instruction and of the semantic properties of irrelevant sounds. Empirical Series 1 showed that episodic recall of lists comprising exemplars drawn from a single semantic-category was disrupted by the lexicality of the irrelevant items and their semantic similarity to the to-be-remembered exemplars, but only when the task-instructions emphasised free, not serial, recall and when the irrelevant category items were dominant exemplars of a category. Moreover this series also demonstrated that irrelevant category items are often included erroneously as responses, and that this is due to a breakdown in the source-monitoring process. These results provide evidence for the interference-by-process construct in that the semantic properties of speech disrupt semantic, and source-monitoring, processing in the focal task and may also produce interference through giving rise to inhibitory processes. Series 2 showed that the presence of semantic properties in the irrelevant sound impaired semantic categorization (or category-clustering) and category, and category-exemplar, recall in the episodic recall of lists of exemplars drawn from several semantic categories, but, like Series 1, failed to produce disruption when task-instruction demanded serial recall. This finding provides yet further evidence for a conflict between two semantic processes. Finally, Series 3 showed that the semantic, but not acoustic, properties of irrelevant sound impaired retrieval from semantic memory when the focal task required retrieval from a semantic-category (requiring semantic processing), but not phonemic-category (not necessitating semantic processing). The implications of the findings for other approaches to auditory-semantic distraction, and auditory distraction generally, are discussed