Synesthesia: Strong and weak

Abstract

In this review, we distinguish strong and weak forms of synesthesia. Strong synesthesia is characterized by a vivid image in one sensory modality in response to stimulation in another one. Weak synesthesia is characterized by cross-sensory correspondences expressed through language, perceptual similarity, and perceptual interactions during information processing. Despite important phenomenological dissimilarities between strong and weak synesthesia, we maintain that the two forms draw on similar underlying mechanisms. The study of strong and weak synesthetic phenomena provides an opportunity to enrich scientists' understanding of basic mechanisms involved in perceptual coding and cross-modal information processing.