Developing the models for Information processing systems
While models like Atkinson and Shiffrin’s (1968) are useful ways to simplify and represent aspects of complex systems, this very complexity requires ongoing adjustment to enable these models to account for additional observations.
For example, the information-processing model made two assumptions:
1. that information could only reach long-term memory by passing through the short-term store; and
2. that rehearsing the information in the short-term store would both retain it in this store, and increase its chance of being selected for transfer to the long-term store.
The first of these assumptions was challenged by the identification of patients who had grossly impaired short-term memory spans and therefore (in terms of the model) severely damaged short-term memory stores, but who appeared to have no impairment in their long-term learning ability (Shallice & Warrington, 1970). The second assumption was called into question by studies where participants rehearsed the last few words of free recall lists for a longer time without showing improvement in the long-term recall of those words (Craik & Watkins, 1973). Under some circumstances, it became clear that encountering the same information on many occasions (which may also be assumed to lead to increased rehearsal) was not sufficient to lead to its retention. For example, people do not remember the details on the faces of the coins that they handle daily (Morris, 1988; Nickerson & Adams, 1979), as you discovered when you tried to sketch a penny at the beginning of the chapter. Other evidence that previously formed the basis for distinguishing between short-term and long-term memory stores has also come into question. For example, the recency effect in free recall had been attributed to the operation of a short-term store because it disappeared when the last few seconds before recall were filled with a task such as backward counting. But when recall was studied under different conditions, recency effects reappeared even without a contribution from short-term memory. When participants studied words and counted backwards after each word in the list, the last few items were better recalled than the middle of the list. This pattern was at odds with the model, because the short-term store should have been ‘filled’ with counting, and so no recency effect should have been observed (e.g. Baddeley & Hitch, 1977; Tzeng, 1973). Semantic encoding was also demonstrated in short-term learning under suitable conditions (Baddeley & Levy, 1971), showing that phonetic encoding was not the only form of coding relevant for the short-term store. Two major responses followed recognition of the problems with the Atkinson and Shiffrin (1968) information-processing model. One approach, especially associated with Baddeley et al. (e.g. Baddeley, 1986), was to enhance the short-term memory model in the light of its known limitations, along with more consideration of the functions that short-term remembering plays in cognition. This change in perspective led to Baddeley’s (1986, 1997, 2001) working memory model. The other response was to question the emphasis on memory stores and their capacity limitations, and to focus instead on an alternative approach based on the nature of the processing that takes place, and its consequences for remembering.
While models like Atkinson and Shiffrin’s (1968) are useful ways to simplify and represent aspects of complex systems, this very complexity requires ongoing adjustment to enable these models to account for additional observations.
For example, the information-processing model made two assumptions:
1. that information could only reach long-term memory by passing through the short-term store; and
2. that rehearsing the information in the short-term store would both retain it in this store, and increase its chance of being selected for transfer to the long-term store.
The first of these assumptions was challenged by the identification of patients who had grossly impaired short-term memory spans and therefore (in terms of the model) severely damaged short-term memory stores, but who appeared to have no impairment in their long-term learning ability (Shallice & Warrington, 1970). The second assumption was called into question by studies where participants rehearsed the last few words of free recall lists for a longer time without showing improvement in the long-term recall of those words (Craik & Watkins, 1973). Under some circumstances, it became clear that encountering the same information on many occasions (which may also be assumed to lead to increased rehearsal) was not sufficient to lead to its retention. For example, people do not remember the details on the faces of the coins that they handle daily (Morris, 1988; Nickerson & Adams, 1979), as you discovered when you tried to sketch a penny at the beginning of the chapter. Other evidence that previously formed the basis for distinguishing between short-term and long-term memory stores has also come into question. For example, the recency effect in free recall had been attributed to the operation of a short-term store because it disappeared when the last few seconds before recall were filled with a task such as backward counting. But when recall was studied under different conditions, recency effects reappeared even without a contribution from short-term memory. When participants studied words and counted backwards after each word in the list, the last few items were better recalled than the middle of the list. This pattern was at odds with the model, because the short-term store should have been ‘filled’ with counting, and so no recency effect should have been observed (e.g. Baddeley & Hitch, 1977; Tzeng, 1973). Semantic encoding was also demonstrated in short-term learning under suitable conditions (Baddeley & Levy, 1971), showing that phonetic encoding was not the only form of coding relevant for the short-term store. Two major responses followed recognition of the problems with the Atkinson and Shiffrin (1968) information-processing model. One approach, especially associated with Baddeley et al. (e.g. Baddeley, 1986), was to enhance the short-term memory model in the light of its known limitations, along with more consideration of the functions that short-term remembering plays in cognition. This change in perspective led to Baddeley’s (1986, 1997, 2001) working memory model. The other response was to question the emphasis on memory stores and their capacity limitations, and to focus instead on an alternative approach based on the nature of the processing that takes place, and its consequences for remembering.
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