Thursday, May 12, 2005

Working memory--TheVillage-2 more

Two more working memory abstracts from TheVillage working memory listserv sent to me today.

  • Author Name(s): Nelson Cowan, Emily M. Elliott, J. Scott Saults, Lara D.; Nugent, Pinky Bomb, and Anna Hismjatullina
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  • Title: Rethinking Speed Theories of Cognitive Development: Increasing the Rate of Recall Without Affecting Accuracy
  • Journal: Psychological Science
  • Abstract: Researchers have suggested that developmental improvements in immediate recall stem from increases in the speed of mental processes. However, that inference has depended on evidence from correlation, regression, and structural equation modeling. We provide counterexamples in two experiments in which the speed of spoken recall is manipulated. In one experiment, second-grade children and adults recalled lists of digits more quickly than usual when the lists were presented at a rapid rate of 2 items per second (items/s). In a second experiment, children received lists at a 1 item/s rate but half of them were successfully trained to respond more quickly than usual, and similar to adults' usual rate. Recall accuracy was completely unaffected by either of these response-speed manipulations. Although response rate is a strong marker of an individual's maturational level, it thus does not appear to determine immediate recall. There are important implications for developmental methodology.
  • Author Name(s): Jefferies, E., Frankish, C., Lambon Ralph, M. A.
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  • Title: Lexical and semantic influences on item and order memory in immediate serial recognition: Evidence from a novel task
  • Journal: QJEP (A)
  • Abstract: Previous studies have reported that, in contrast to immediate serial recall, lexical/semantic factors have little effect on immediate serial recognition: this has been taken as evidence that linguistic knowledge contributes to verbal short-term memory in a redintegrative process at recall. Contrary to this view, we found that lexicality, frequency and imageability all influenced matching span. The standard matching span task, requiring changes in item order to be detected, was less susceptible to lexical/semantic factors than a novel task involving the detection of phoneme order and hence item identity changes. Therefore, in both immediate recognition and immediate serial recall, lexical/semantic knowledge makes a greater contribution to item identity as opposed to item order memory. Task sensitivity, and not the absence of overt recall, may have underpinned previous failures to show effects of these variables in immediate recognition. We also compared matching span for pure and unpredictable mixed lists of words and nonwords. Lexicality had a larger impact on immediate recognition for pure as opposed to mixed lists, in line with findings for immediate serial recall. List composition affected the detection of phoneme but not item order changes in matching span; similarly, in recall, mixed lists produce more frequent word phoneme migrations but not migrations of entire items. These results point to strong similarities between immediate serial recall and recognition. Lexical/semantic knowledge may contribute to phonological stability in both tasks.

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