Picture Naming or Word Reading: Does the Modality Affect Speech Motor Adaptation and Its Transfer?

Auditory-motor adaptation and transfer paradigms are increasingly used to explore speech motor control as well as phonological representations underlying speech production. Auditory-motor adaptation is generally assumed to occur at the sensory-motor level. However, few studies suggested that linguistic or contextual factors such as the modality of presentation of stimuli influences adaptation. The present study investigates the influence of the modality of stimuli presentation (written word vs. a picture representing the same word) on auditory-motor adaptation and transfer. In this speech production experiment, speakers' auditory feedback was altered online, inducing adaptation. We contrasted the magnitude of adaptation in these two different modalities and we assessed transfer from /pe/ to the French word /epe/ in the same vs. different modality of presentation, using a mixed 2*2 subject design. The magnitude of adaptation was not different between modalities. This observation contrasts with recent findings showing an effect of the modality (a written word vs. a go signal) on adaptation. Moreover, transfer did occur from one modality to the other, and transfer pattern depended on the modality of transfer stimuli. Overall, the results suggest that picture naming and word reading rely on sensory-motor representations that may be linked to contextual (or surface) characteristics.