Subvocalization in auditory-verbal imagery: just a form of motor imagery?

摘要

Previous studies have provided evidence for subvocal rehearsal ("inner voice") and phonological storage ("inner ear") in auditory-verbal imagery. The question remains to be answered whether the inner voice mainly involves higher-order language systems, or primarily relies on motor systems associated with articulatory-kinesthetic processing. On the basis of models of auditory imagery and working memory, we predicted that, if auditory-verbal imagery is a form of motor imagery, performance on a novel auditory-verbal imagery task would be affected by concurrent articulatory suppression as well as by concurrent finger tapping. In contrast, we predicted that performance on a visuospatial control task would be significantly affected by concurrent tapping only. The auditory imagery task consisted of indicating, for bisyllabic words, the syllable that carried the stress. A significant interaction was observed between task (verbal vs. visual) and type of interference (articulatory suppression vs. tapping). Tapping affected reaction times on the visual task significantly more than articulatory suppression. However, both interference conditions affected the verbal task to an equal extent. The present findings confirm the role of subvocalization in auditory-verbal imagery and provide evidence for a strong involvement of articulatory-kinesthetic motor processing.