ABSTRACT
In the late 1970s a question was discussed in cognitive psychology whether the information contained in the semantic system might be organised in independent compartments in which information acquired through a sensory modality would remain independent of information acquired through a different sensory modality. Popular examples of this view are models encompassing two distinct types of semantic representation: a visual and a verbal one, the latter mainly built on the basis of acoustic/linguistic information (see Potter & Faulconer, 1975; Seymour, 1979; Snodgrass, 1984). At about the same time, neuropsychological cases featuring dissociations seemingly supporting such distinctions were beginning to be described (e.g. Beauvois, 1982; Warrington, 1975). Within a few years the debate massively invaded neuropsychology, since an impressive variety of dissociations concerning lexical/semantic abilities were reported. Distinctions in the semantic system apparently implemented in a different neuroanatomy were not limited to information coming from different modalities. The semantic category of the lexical item also appeared to determine a different neural organisation. Already in the 1960s, Goodglass et al. (1966) had convincingly shown that some semantic categories could be either selectively spared or impaired in aphasia. These somewhat specific disturbances in some cases seemed to concern only the input or the output processes, while in other cases all the information in a single semantic realm was apparently lost or disrupted. Semantic category and modality of input were thought to be related to each other and the study of this relation brought to light some very interesting generalisations.
