Memory systems: The case of phonological short-term memory. A festschrift for Cognitive Neuropsychology

Developments in the understanding of the neurological and functional architectures of phonological short-term memory that took place in the 1984-2004 time period are reviewed. Phonological short-term memory is discussed as a case that illustrates a number of issues shared by other research domains in cognitive neuropsychology, with particular reference to memory systems. Modularity: Phonological short-term memory includes two main components, an input storage system (the phonological short-term store), and an output rehearsal process. These components are functionally connected with other verbal processes and systems, such as visual-verbal short-term memory, phonological recoding (grapheme-to-phoneme conversion), verbal long-term episodic memory, and the lexical systems. Neurological specificity: The store and the rehearsal components of phonological memory are implemented in discrete parts of the left cerebral hemisphere. Both the traditional anatomo-clinical correlation studies in brain-damaged patients, and neuroimaging activation experiments in neurologically unimpaired subjects, have contributed to elucidate the neural basis of the system. Converging operations: A distinctive feature of these advances has been the close interaction and cross-fertilisation among the related domains of cognitive experimental psychology and cognitive neuropsychology, based on observations in adult and child populations, in brain-damaged patients, and in subjects with developmental and genetically based cognitive disorders. Data from these different research areas have converged to specify the structure of phonological short-term memory (the distinction between storage and rehearsal) and its relationships with other memory systems (the long-term learning of novel phonological lexical entries).