Is the word “ambulance” noisy for deaf people? Investigating the perceptual grounding of words in early deaf individuals

Abstract

How does the semantic system reorganize following the deprivation of one sensory modality? The embodiment theory claims that semantic representation is grounded in the sensory-motor system, so it predicts that a deficit in the sensory-motor system may cause impairments in word processing. Studies on congenital blindness reveal close similarities in the semantic representations of blind and sighted individuals. Deafness, however, other than being a sensory deprivation, also entails an impoverished language knowledge. In the present study, we investigate the sensory experience of early deaf individuals on word meaning, questioning whether the mechanisms responsible for semantic grounding in perceptual information are preserved despite the lack of auditory experience.

To this aim, in our experiment we investigated the sensory experience evoked by 200 Italian words in early deaf individuals measuring their perceptual strength. For each item, participants (N = 37) were instructed to evaluate the extent to which they could experience that word by each of the five senses (by hearing, by tasting, by feeling through touch, by smelling, and by seeing) replying on a five-point scale. Participants also performed the LexITA test, a short and reliable vocabulary test which measures lexical proficiency for Italian. In line with the embodiment theory, results show a minor contribution of the auditory modality as compared to the hearing population, which in turn led to a greater involvement of the other sensory modalities, thus suggesting that words were experienced in a more multimodal way.