Chapter 5
Summary
- Evidence suggests that there are two separate memory stores, known as ‘short-term memory’ (or ‘working memory’) and ‘long-term memory’ (or ‘storage memory’).
- Evidence for the distinction between these two stores arises from clinical studies showing that amnesics may suffer damage to one store whilst the other remains intact.
- The short-term working memory is assumed to function as an active mental workspace in which a variety of processing operations are carried out. In contrast, the long-term storage memory is seen as a passive storage space.
- Baddeley and Hitch (1974) have proposed a widely accepted model of working memory which comprises a central executive served by two short-term stores, the ‘phonological loop’ and the ‘visuo-spatial sketchpad’.
- Evidence for the existence of these memory systems has come from experiments showing that two tasks will interfere with one another if they make use of the same WM component.
- The phonological loop is assumed to provide brief storage for auditory input, and it is thought to play a major role in the use and development of language.
- The visuo-spatial sketchpad holds visual images, and it is also thought to be involved in involved in visual pattern recognition, and in the perception and control of movement.
- The central executive is assumed to be the main focus of conscious awareness, and it appears to be involved in mental abilities such as decision making, planning and problem solving.
- Recently, an additional loop has been postulated called the ‘episodic buffer’, which integrates information from a variety of sense modalities, providing a link between the WM and the LTM.
- Impairment of the central executive is known as ‘dysexecutive syndrome’, and it has been found to be associated with frontal lobe lesions. It is considered to play a part in certain clinical disorders such as Alzheimer’s disease, autism and schizophrenia.
- The development of neuro-imaging technology has made it possible to investigate which parts of the brain are involved in the activities of the working memory and its various components.
- The working memory model has been very influential, but in recent years it has received some criticism, and alternative models have been proposed.
Glossary
Articulatory suppression A task used to occupy the articulatory control process of the working memory, normally involving the repetition of a sound (such as ‘the’) which requires articulation but little processing.
Central executive A hypothetical mechanism which is believed to be in overall control of the working memory. It is assumed to control a variety of tasks, such as decision-making, problem-solving and selective attention.
Digit span A measure of the largest number of digits which an individual can recall when tested immediately after their presentation. Widely used as a test of the capacity of the phonological component of the working memory.
Dysexecutive syndrome A collection of deficits observed in frontal lobe patients which may include impaired concentration, impaired concept formation, disinhibition, inflexibility, perseveration, impaired cognitive estimation and impaired strategy formation.
Episodic buffer A hypothetical component of working memory which integrates information from different sense modalities, and provides a link with the long-term memory.
Phonological loop A hypothetical component of working memory, which is assumed to provide brief storage for verbally presented items.
Recency and primacy effects The tendency for participants to show particularly good recall for items presented towards the end (recency) or the start (primacy) of a list.
Visuo-spatial sketchpad A hypothetical component of working memory, which is assumed to provide brief storage for visually presented items.
Word-length effect The finding that word span in immediate recall is greater for short words than for long words.
Working memory (WM) A hypothetical short-term memory system which serves as a mental workspace in which a variety of processing operations are carried out on both new input and retrieved memories.
Phonological and semantic similarity
Working memory span
Working memory
Capacity in short-term memory
Duration in short-term memory
Further Reading
Baddeley, A.D. (2009). Working Memory. In Baddeley, A.D., Eysenck, M.W., & Anderson, M.C. (Eds) Memory.Hove: Psychology Press.
Heathcote D. (2005). Working Memory and Performance Limitations. In Esgate A., & Groome D. (Eds) An Introduction to Applied Cognitive Psychology, Hove: Psychology Press.
Miyake, A., Friedman, N. P., Emerson, M. J., Witzki, A. H., Howerter, A., & Wager, T. D. (2000). The unity and diversity of executive functions and their contributions to complex “frontal lobe” tasks: A latent variable analysis. Cognitive Psychology, 41( 1), 49–100.
http://www.sciencedirect.com/science/article/pii/S001002859990734X