Although the Alternative Uses divergent thinking task has been widely used in psychometric and experimental studies of creativity, the cognitive processes underlying this task have not been examined in detail before the two studies are reported here. In Experiment 1, a verbal protocol analysis study of the Alternative Uses task was carried out with a Think aloud group (N=40) and a Silent control group (N=64). The groups did not differ in fluency or novelty of idea production indicating no verbal overshadowing. Analysis of protocols from the Think aloud group suggested that initial responses were based on a strategy of Retrieval from long-term memory of pre-known uses. Later responses tended to be based on a small number of other strategies: property-use generation, imagined Disassembly of the target object into components and scanning of Broad Use categories for possible uses of the target item. Novelty of uses was particularly associated with the Disassembly strategy. Experiment 2 (N=103) addressed the role of executive processes in generating new and previously known uses by examining individual differences in category fluency, letter fluency and divergent task performance. After completing the task, participants were asked to indicate which of their responses were new for them. It was predicted and found in regression analyses that letter fluency (an executively loading task) was related to production of 'new' uses and category fluency was related to production of 'old' uses but not vice versa.

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Two experiments examined the generalizability of the effects of word length and phonological similarity with visual and auditory presentation in immediate verbal serial ordered recall. In Experiment 1, data were collected from 251 adult volunteers drawn from a broad cross-section of the normal population. Word length and phonological similarity in both presentation modes significantly influenced the group means. However, 43% of the subjects failed to show at least one of the effects, and the likelihood that effects appeared was highly correlated with verbal memory span. In Experiment 2, 40 subjects of the original sample were retested, 20 of whom had failed to show one or more effects in Experiment 1. Whether or not an effect had appeared for individual subjects on the first test session was a poor predictor of whether the effect would appear on retest. Finally,an analysis of subject reports demonstrated that the patterns of experimental data could be accounted for in part by the strategies that subjects reported using, and the effect of strategy was independent of the effect of span. The implications of these findings for theories of verbal short-term memory are discussed.Current views as to the characteristics of verbal shortterm memory owe much to the discovery and exploration of the effects on immediate serial ordered recall of word length and phonological similarity. The word-length effect refers to the tendency for normal adult subjects to have more difficulty in immediate serial ordered recall of a sequence oflong words (e.g., university, aluminium, hippopotamus, refrigerator) than in that of a sequence of short words (e.g., scroll, switch, zinc, maths). The phonological similarity effect arises from the relative difficulty in serial ordered recall of phonologically similar items (e.g., man, mad, map, mat) compared with recall ofa sequence of items that are phonologically distinct (e.g., day, boy, sup,few). Word-length and phonological similarity effects appear whether the subjects read or listen to the word sequence for recall.These are robust effects that have been replicated widely with a range of materials using groups of normal subjects (e.g., Baddeley, Thomson, & Buchanan, 1975; Caplan, Ro-Part ofthe work on which this paper is based was supported by a travel grant given to the first author from the Trustees of the journal Brain. We are grateful to Alan Baddeley for very helpful discussions on this topic, and to Marc Marschark for useful discussions on the incidence of head injury in the college population. We are also grateful to Nelson Cowan

The role of visual working memory in temporary serial retention of verbal information was examined in four experiments on immediate serial recall of words that varied in visual similarity and letters that varied in the visual consistency between upper and lower case. Experiments 1 and 2 involved words that were either visually similar (e.g. fly, cry, dry; hew, new, few) or were visually distinct (e.g. guy, sigh, lie; who, blue, ewe). Experiments 3 and 4 involved serial recall of both letter and case from sequences of letters chosen such that the upper- and lower-case versions were visually similar, for example Kk, Cc, Zz, Ww, or were visually dissimilar, for example Dd, Hh, Rr, Qq. Hence in the latter set, case information was encoded in terms of both the shape and the size of the letters. With both words and letters, the visually similar items resulted in poorer recall both with and without concurrent articulatory suppression. This visual similarity effect was robust and was replicated across the four experiments. The effect was not restricted to any particular serial position and was particularly salient in the recall of letter case. These data suggest the presence of a visual code for retention of visually presented verbal sequences in addition to a phonological code, and they are consistent with the use of a visual temporary memory, or visual "cache", in verbal serial recall tasks.

It has often been asserted that working-memory limitations are a major factor contributing to problem difficulty; for example, Johnson-Laird's (1983) mental-models theory appeals to workingmemory limitations to explain the difficulty of syllogistic reasoning. However, few studies have directly explored working memory in problem solving in general or syllogistic reasoning in particular. This paper reports two studies. In the first, working-memory load was varied by presenting syllogistic tasks either verbally or visually (so that the premises were continuously available for inspection). A significant effect of memory load was obtained. In the second study, premises were presented visually for a subject-determined time. Dual-task methods were used to assess the role of working-memory components, as identified in Baddeley's (1986) model. Syllogistic performance was disrupted by concurrent random-number generation but not by concurrent articulatory suppression or by concurrent tapping in a preset pattern. Furthermore, the concurrent syllogism task interfered with random generation and to a lesser extent with articulatory suppression, but not with tapping. We conclude that while the central-executive component of working memory played a major role in the syllogistic-task performance reported here, the articulatory loop had a lesser role, and the visuospatial scratch pad was not involved.

The Tower of London (TOL) task has been used extensively as a test of planning ability in neuropsychological patients and normal populations. Participants are asked to preplan mentally a sequence of moves to match a start set of discs to a goal, and then to execute the moves one by one. The mental preplanning stage has been identified as critical to efficient performance. The current experiments examined whether manipulations of mental preplanning influence performance on the TOL. In Experiment 1, the effect of different planning instructions was examined. Those told to make full mental plans spent considerably longer in planning than participants given no specific planning instructions, yet there was no effect of instruction condition on the efficiency of executing plans. Experiment 2 investigated whether people were able to plan mentally, by looking at their ability to identify intermediate states of an optimum mental plan. Results indicated that most individuals could make accurate preplans up to two subgoals ahead, but not three. However, making an efficient preplan did not result in better subsequent execution of moves to solve the TOL trial. It is concluded that people can make effective mental plans for a limited number of moves. However, on the TOL task, mental preplanning does not offer benefits in terms of quicker performance, or more accurate solution. The nature of planning in the TOL task is therefore questioned.

The role of visual working memory in temporary serial retention of verbal information was examined in four experiments on immediate serial recall of words that varied in visual similarity and letters that varied in the visual consistency between upper and lower case. Experiments 1 and 2 involved words that were either visually similar (e.g. fly, cry, dry; hew, new, few) or were visually distinct (e.g. guy, sigh, lie; who, blue, ewe). Experiments 3 and 4 involved serial recall of both letter and case from sequences of letters chosen such that the upper- and lower-case versions were visually similar, for example Kk, Cc, Zz, Ww, or were visually dissimilar, for example Dd, Hh, Rr, Qq. Hence in the latter set, case information was encoded in terms of both the shape and the size of the letters. With both words and letters, the visually similar items resulted in poorer recall both with and without concurrent articulatory suppression. This visual similarity effect was robust and was replicated across the four experiments. The effect was not restricted to any particular serial position and was particularly salient in the recall of letter case. These data suggest the presence of a visual code for retention of visually presented verbal sequences in addition to a phonological code, and they are consistent with the use of a visual temporary memory, or visual "cache", in verbal serial recall tasks.

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