The phonological loop
Much research has been concentrated on the phonological loop. By using a technique known as articulatory suppression, in which research participants repeat aloud (or silently) a simple sound or word, such as ‘la la la’ or ‘the the the’, the phonological loop can be prevented temporarily from retaining any further information. So contrasting performance with and without articulatory suppression demonstrates the contribution of the phonological loop. Like any loop, the phonological loop has a finite length. That length could be specified as a number of items or as a length of time. Baddeley, Thomson and Buchanan (1975) investigated this question. They showed that memory span – the number of words that you can hear and then repeat back without error – is a function of the length of time that it takes to say the words. A word list like ‘mumps, stoat, Greece, Maine, zinc’ is much easier to remember in a short-term memory test than ‘tuberculosis, hippopotamus, Yugoslavia, Louisiana, titanium’, even though the two l sts are matched in terms of the number of words and the meaning. This word length effect is eliminated if the participants have to carry out articulatory suppression while they study the list.
Another example comes from the varying speed with which the digits 1 to 10 can be pronounced in different languages. The size of the memory span for people who speak each language is highly correlated with the speed with which the digits can be spoken in that language (Naveh-Benjamin & Ayres, 1986). These and other observations demonstrate that the phonological loop must be time-limited. The central executive and the sketch pad More recently, Baddeley and his associates have turned to studying the central executive. Their technique is to ask people to perform two tasks at the same time. One of the tasks (the first task) is designed to keep the central executive busy, while the second task is being evaluated for whether the central executive is involved in its performance. When performance on the second task suffers due to the presence of the first task, they conclude that the central executive is involved in performing the second task. One task used to engage the central executive is the generation of random etter sequences. Participants generate letter sequences taking care to avoid sequences of letters that fall into meaningful orders, such as (T, V), (B, B, C) or (U, S, A). Participants must attend carefully to their letter choice, and this monitoring occupies the central executive. Robbins et al. (1996) showed that the memory of expert chess players for positions taken from actual chess games was impaired by the letter generation task but not by articulatory suppression, indicating that the central executive was involved in remembering the chess positions. These researchers also found that another task which is believed to interfere with the visuo-spatial sketch pad also reduced chess performance, reflecting the contribution of spatial short-term memory in the reproduction of the chess layouts. The episodic buffer Information that is retrieved from long-term memory often needs to be integrated to be appropriate for the current demands upon working memory. This is an important function of the episodic buffer p oposed by Baddeley (2001). Baddeley gives the example of imagining an elephant who plays ice-hockey. We can easily go beyond the information about elephants and ice-hockey our longterm memory supplies us to imagine how the elephant holds the hockey stick and what position it might play. The episodic buffer allows us to go beyond what already exists in long-term memory, to combine it in different ways, and to use it to create novel situations on which future action can be based.
Much research has been concentrated on the phonological loop. By using a technique known as articulatory suppression, in which research participants repeat aloud (or silently) a simple sound or word, such as ‘la la la’ or ‘the the the’, the phonological loop can be prevented temporarily from retaining any further information. So contrasting performance with and without articulatory suppression demonstrates the contribution of the phonological loop. Like any loop, the phonological loop has a finite length. That length could be specified as a number of items or as a length of time. Baddeley, Thomson and Buchanan (1975) investigated this question. They showed that memory span – the number of words that you can hear and then repeat back without error – is a function of the length of time that it takes to say the words. A word list like ‘mumps, stoat, Greece, Maine, zinc’ is much easier to remember in a short-term memory test than ‘tuberculosis, hippopotamus, Yugoslavia, Louisiana, titanium’, even though the two l sts are matched in terms of the number of words and the meaning. This word length effect is eliminated if the participants have to carry out articulatory suppression while they study the list.
Another example comes from the varying speed with which the digits 1 to 10 can be pronounced in different languages. The size of the memory span for people who speak each language is highly correlated with the speed with which the digits can be spoken in that language (Naveh-Benjamin & Ayres, 1986). These and other observations demonstrate that the phonological loop must be time-limited. The central executive and the sketch pad More recently, Baddeley and his associates have turned to studying the central executive. Their technique is to ask people to perform two tasks at the same time. One of the tasks (the first task) is designed to keep the central executive busy, while the second task is being evaluated for whether the central executive is involved in its performance. When performance on the second task suffers due to the presence of the first task, they conclude that the central executive is involved in performing the second task. One task used to engage the central executive is the generation of random etter sequences. Participants generate letter sequences taking care to avoid sequences of letters that fall into meaningful orders, such as (T, V), (B, B, C) or (U, S, A). Participants must attend carefully to their letter choice, and this monitoring occupies the central executive. Robbins et al. (1996) showed that the memory of expert chess players for positions taken from actual chess games was impaired by the letter generation task but not by articulatory suppression, indicating that the central executive was involved in remembering the chess positions. These researchers also found that another task which is believed to interfere with the visuo-spatial sketch pad also reduced chess performance, reflecting the contribution of spatial short-term memory in the reproduction of the chess layouts. The episodic buffer Information that is retrieved from long-term memory often needs to be integrated to be appropriate for the current demands upon working memory. This is an important function of the episodic buffer p oposed by Baddeley (2001). Baddeley gives the example of imagining an elephant who plays ice-hockey. We can easily go beyond the information about elephants and ice-hockey our longterm memory supplies us to imagine how the elephant holds the hockey stick and what position it might play. The episodic buffer allows us to go beyond what already exists in long-term memory, to combine it in different ways, and to use it to create novel situations on which future action can be based.
No comments:
Post a Comment