Kosenko A.

Yuri Fedkovych Chernivtsi National University

Verbal working memory and sentence comprehension

Psycholinguistics is the study of psychological states and mental activity associated with the use of language [1]. Psycholinguists work to develop models for how language is processed and understood, using evidence from studies of what happens when these processes go awry [2]. Research in psychology has provided considerable evidence for a division between long-term memory, in which memories of large numbers of facts and autobiographical events are maintained for up to years, and short-term memory, which is capable of retaining small amounts of information for very short periods of time [3]. Baddeley and his colleagues introduced the powerful concept that the appropriate way to characterize short-term memory is as a working memory system [4; 755-764]. Working memory is conceived of as a short-duration limited-capacity memory system capable of simultaneously storing and manipulating information in the service of accomplishing a task. Appeal to the notion of a limited-capacity working memory system (or to equivalent concepts such as processing resources”) to account for features of human cognitive performance is widespread in cognitive psychology, with respect to both normal functions and the abilities of subjects with developmental and acquired cognitive disorders. Baddeley and his colleagues proposed the first model of the functional architecture of human working memory. In his model working memory is made up of three main components - the central executive, the articulatory loop, and the visual-spatial scratch pad. The articulatory loop and the visual-spatial scratch pad are slave systems in which verbal and visual information respectively are stored when the central executive is overloaded. One can conceive of these components as responsible for maintaining short-term information availability. The central executive is the workhorse and mastermind of human cognition. It allocates attention to a task and performs information storage and computational functions within a given task. To determine the working memory requirements of a task, Baddeley's theory of the functional architecture of working memory needs to be supplemented by specific models of the computational demands that individual cognitive processes make on the central executive. Current models of cognitive processes provide such measures. Implemented models provide specific quantitative measurements of the computational and storage demands of a task. For instance, in procedural models a measure of the working memory requirements of a computation might be the number of procedures required to reach a subgoal and the number of elements maintained in each procedure. In contrast, measures of working memory requirements derived from neural net models would be quite different, and might consist of the number of steps that are needed to gravitate towards an attractor in a neural network. The working memory demands are usually taken to be the sum of the working memory requirements of the functions that are active at that point in the task. Many valuable models of cognitive phenomena are not implemented, but still provide guides to the relative complexity of one operation, or set of operations, over another. Research into the role of working memory in cognitive processes regularly appeals to all these types of models to provide the basis for the determination of the processing demands of a task and of those demands at a particular point of processing within a task. There is considerable evidence for a division of the central executive of the working memory system into visual and verbal components [5]. Particular interest is in the distinction between the extraction of meaning from a linguistic signal, (“interpretive processing”) and in the use of that meaning to accomplish other tasks such as storing information in long term semantic memory, reasoning, planning actions, and other functions (“post-interpretive processing”). By interpretive processing we refer to the processes of recognizing words and appreciating their meanings and syntactic features, constructing syntactic and prosodic representations, and assigning thematic roles, focus and other aspects of propositional and discourse-level semantics. Many linguists and psycholinguists have argued that the processes involved in interpretive processing are distinct from those involved in other verbally mediated functions (Fodor, Forster, Frazier). Arguments regarding the modularity of interpretive processing have largely centered on the issue of what types of information are used in the initial determination of linguistic form and meaning. The question of a cognitive specialization for interpretive processing is to be addressed from the point of view of the structure of working memory. The results of a variety of experiments  suggest that the working memory system that is called on in interpretive processing at the sentence level - assigning the syntactic structure of a sentence and using that structure to determine the meaning of the sentence - constitutes a separate subsystem within verbal working memory. This subsystem of verbal working memory is involved in the set of related operations that is responsible for identifying linguistic elements and structures and determining the preferred literal meaning of an utterance.

Bibliography:

1.     Columbia Electronic Encyclopedia, 6th ed. Copyright © 2006, Columbia University Press.

2.     Eastman, Carol M., and Longyear, Christopher. "Linguistics." Microsoft® Encarta® 2006 [DVD]. Redmond, WA: Microsoft Corporation, 2005.

3.     Squire, L. R., & Zola-Morgan, S. . The medial temporal lobe memory system. 1991.

4.     Baddeley, A. . Working Memory. In M. S. Gazzaniga (Ed.), The Cognitive Neurosciences. Campidge, Mass.: The MIT Press. 1995.

5.     Shah, P., & Miyake, A. . The separability of working memory resources for spatial thinking and language processing: An individual differences approach. 1996