K. J. Gilhooly

Counting on working memory in arithmetic problem solving

Mental calculation is an important everyday skill involving access to well-learned procedures, problem solving, and working memory. Although there is an active literature on acquiring concepts and procedures for mental arithmetic, relatively little is known about the role of working memory in this task. This paper reports two experiments in which dual-task methodology is used to study the role of components of working memory in mental addition. In Experiment 1, mental addition of auditorily presented two-digit numbers was significantly disrupted by concurrent random letter generation and, to a lesser extent, by concurrent articulatory suppression, but was unimpaired by concurrent hand movement or by presentation of irrelevant pictures. Although the number of errors increased with two of the dual tasks, the incorrect responses tended to be quite close to the correct answer. In Experiment 2, the numbers for addition were presented visually. Here again, random generation produced the largest disruption of mental arithmetic performance, while a smaller amount of disruption was observed for articulatory suppression, hand movement, and unattended auditorily presented two-digit numbers. The overall levels of performance were better and the absolute size of the disruptive effects shown with visual presentation was very small compared with those found for auditory presentation. This pattern of results is consistent with a role for a central executive component of working memory in performing the calculations required for mental addition and in producing approximately correct answers. Visuospatial resources in working memory may also be involved in approximations. The data support the view that the subvocal rehearsal component of working memory provides a means of maintaining accuracy in mental arithmetic, and this matches a similar conclusion derived from previous work on counting. The general implications for the role of working memory in arithmetic problem solving will be discussed.

Working memory and strategies in syllogistic-reasoning 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 working memory 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 continuous1y avai1ab1e 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.

Age-of-acquisition effects in lexical and episodic memory tasks

This paper reports four experiments on the effects of word age of acquisition in verbal tasks. In all cases, multiple-regression analysis was used to assess the relative effects of age as opposed to other potentially relevant word attributes. Experiments 1 and 2 concerned lexical memory tasks. In Experiment 1, picture naming speeds were found to be mainly determined by picture codability and name age of acquisition. In Experiment 2, it was found that when subjects produced words in response to bigram cues, early acquired target words were more likely to be produced than later acquired words, even when frequency and other word attributes were taken into account. The remaining two experiments dealt with the episodic memory tasks of free recall and recognition. No age effects were found in these tasks. It was concluded that early age of acquisition facilitates retrieval from lexical memory but has no significant effect in episodic memory tasks.

Skill in map reading and memory for maps

Studies of expertise have typically shown that experts have better memory for materials from their fields than do novices. However, previous research on memory for maps has not shown the expected effect of expertise. The present study differed from previous studies by using contour maps as well as planimetric maps. In Experiment 1 the expected superiority in memory performance was found for skilled map readers when contour maps were used, but not when planimetric maps were used. In Experiment 2, the main results of Experiment 1 were replicated, and, in addition, process tracing data were obtained during both study and test phases of contour map learning. Objective measures of attentional and retrieval focussing revealed almost no differences between the skilled and unskilled subjects. However, analyses of verbal protocols showed that the skilled subjects made more use of specialist schemata, whereas the unskilled subjects spent more time in reading place names. During recall, the skilled subjects made more use of both specialist and “lay” schemata, whereas the unskilled retrieved more place-name information. The results are interpreted in terms of a schema-based approach to expertise.

Word age-of-acquisition, reading latencies and auditory recognition.

This paper reports two experiments concerning the effects of word age-of-acquisition on word naming speed and auditory recognition of words presented at a low volume. The first experiment found significant facilitating effects of word age-of-acquisition in word naming even when word length, frequency and familiarity were taken into account. The second experiment found no evidence of age-of-acquisition effects in auditory word recognition. The results are interpreted as supporting the view that the age-of-acquisition variable mainly affects word production and has little effect on word recognition processes.

Syllogistic Reasoning Tasks, Working Memory, and Skill

The involvement of working memory sub-systems in syllogistic reasoning problems was assessed by dual task methods. Effects of skill level and training on working memory involvement in syllogistic reasoning were examined. In Study 1, participants were pre-selected into groups of High and Low skill at syllogistic reasoning on the basis of a pencil-and-paper screening test. Six separate High and Low skill groups completed syllogistic reasoning tasks in control conditions and each group was also tested under one of the following six dual task conditions: articulatory suppression, unattended speech, verbal random generation, spatial random generation, tapping in a simple pattern, unattended pictures. The results indicated that the more skilled participants were generally following a high demand strategy, which loaded the central executive, phonological loop and imagery sub-systems, but that lower skill participants were generally following a less demanding strategy which did not load working memory components ...

Word age-of-acquisition and lexical decision making ☆

Abstract This paper reports two experiments concerning the effects of word age-of-acquisition and other word attributes on speed of lexical decision. Analyses of group average data indicated that word length, frequency and familiarity were the major determinants of decision speed. Previous reports of age-of-acquisition effects on lexical decision are attributed to failures to control for word familiarity.

Concrete and abstract terms and relations in testing a rule

Subjects have more difficulty in correctly testing a conditional rule stated in abstract form than the same rule given in “thematic” form. The “thematic” form of the rule involves both concrete terms and a concrete relation. Four experimental conditions were formed by combining concrete abstract terms and relations. Fifty subjects were tested in each condition. The results indicated that concrete-ness of the terms is the main factor leading to improved performance with “thematic” as against abstract material in the rule testing task.

Word age-of-acquisition and residence time in lexical memory as factors in word naming

Previous reports of age-of-acquisition effects have been theoretically ambiguous since, in any particular individual, word age-of-acquisition is perfectly correlated with the length of time that a word has been known. The study reported in this article attempted to disentangle effects of word age-of-acquisition and length of word residence time in lexical memory. To this end, words varying in recency-of-introduction to British English were presented in a word-naming task to 46 native speakers whose ages ranged from 20 to 58 years. Using subjects’ ratings of the words on age-of-acquisition, it was possible to assess word residence times and to compare the effects on naming speeds of age-of-acquisition and residence times. Regression analyses indicated that age-of-acquisition was a more important factor than residence time in the word-naming task.

Expertise and the interpretation of computerized physiological data: implications for the design of computerized monitoring in neonatal intensive care

This paper presents the outcomes from a cognitive engineering project addressing the design problems of computerized monitoring in neonatal intensive care. Cognitive engineering is viewed, in this project, as a symbiosis between cognitive science and design practice. A range of methodologies has been used: interviews with neonatal staff, ward observations and experimental techniques. The results of these investigations are reported, focusing specifically on the differences between junior and senior physicians in their interpretation of monitored physiological data. It was found that the senior doctors made better use of the different knowledge sources available than the junior doctors. The senior doctors were able to identify more relevant physiological patterns and generated more and better inferences than did their junior colleagues. Expertise differences are discussed in the context of previous psychological research in medical expertise. Finally, the paper discusses the potential utility of these outcomes to inform the design of computerized decision support in neonatal intensive care.