The role of working memory in the carry operation of mental arithmetic: number and value of the carry

Two experiments were conducted to investigate the role of phonological and executive working-memory components in the carry operation in mental arithmetic. We manipulated the number of carry operations, as previous research had done, but also the value that had to be carried. Results of these experiments show that in addition to the number of carry operations, the value of the carry is also an important variable determining the difficulty of arithmetical sums. Furthermore, both variables (number and value) interacted with each other in such a way that the combination of multiple carries and values of carries larger than one resulted in more difficult problems irrespective of the presence of a working-memory load. The findings with respect to working-memory load suggest that mainly the central executive is important in handling the number of carry operations as well as the value that has to be carried. The implications of the present findings for our views on mental arithmetic and its reliance on working memory are discussed.     

The role of working memory in the carry operation of mental arithmetic: Number and value of the carry

Two experiments were conducted to investigate the role of phonological and executive working-memory components in the carry operation in mental arithmetic. We manipulated the number of carry operations, as previous research had done, but also the value that had to be carried. Results of these experiments show that in addition to the number of carry operations, the value of the carry is also an important variable determining the difficulty of arithmetical sums. Furthermore, both variables (number and value) interacted with each other in such a way that the combination of multiple carries and values of carries larger than one resulted in more difficult problems irrespective of the presence of a working-memory load. The findings with respect to working-memory load suggest that mainly the central executive is important in handling the number of carry operations as well as the value that has to be carried. The implications of the present findings for our views on mental arithmetic and its reliance on working memory are discussed.     

The role of phonological and visual working memory in complex arithmetic for Chinese- and Canadian-educated adults

Two experiments were conducted to test cultural differences in the role of phonological and visual working memory in complex arithmetic. Canadian- and Chinese-educated students solved complex subtraction problems (e.g., 85 − 27; Experiment 1) and complex multiplication problems (e.g., 6 − 13; Experiment 2) under phonological and visual working memory loads. Problem complexity (i.e., borrow or carry operations) and presentation format (i.e., horizontal vs. vertical) were also manipulated. The results showed that both Chinese- and Canadian-educated participants relied on both phonological and visual working memory resources when solving complex subtraction and multiplication problems. Selective involvement of phonological and visual working memory as a function of operation (Lee & Kang, 2002) or presentation format (Trbovich & LeFev re, 2003) was found only for Chinese-educated participants and not for Canadian-educated participants, calling into question the generalizability of these findings across arithmetic operations and cultural groups.     

The role of working memory in analogical mapping

The impact of a working-memory load on analogical mapping was examined in two experiments, using a dual-task paradigm. In Experiment 1, we used a phonological working-memory load; in Experiment 2, we used a phonological working-memory load and an executive working-memory load. The subjects were required to identify correspondences between visual scenes, either for single objects or for three objects simultaneously. The results indicated that the imposition of either a phonological or an executive working-memory load decreased the frequency with which the subjects identified correspondences between scenes based on relations and increased the frequency with which they identified correspondences based on object attributes. The frequency with which subjects made relational mappings was increased by the instruction to find correspondences for multiple objects in a scene simultaneously, rather than for just one. These results indicate that mapping on the basis of relations places greater demands on both modality-specific buffers and executive components of working memory than does mapping on the basis of object attributes.     

Working-memory and auditory localization: Demand for central resources impairs performance

Four experiments explored possible roles for working memory in sound localization. In each experiment, the angular error of localization was assessed when performed alone, or concurrently with a working-memory task. The role of the phonological slave systems in auditory localization was ruled out by Experiments 1 and 2, while an engagement of central resources was suggested by the results of Experiment 3. Experiment 4 examined the involvement of visuo-spatial systems in auditory localization and revealed impairment of localization by the concurrent spatial working-memory task. A comparison of dual-task decrement across all four studies suggests that localization places greater demand on central than on spatial resources.     

New Insights into the role of the phonological loop in task switching: evidence from three different age groups

ABSTRACT

The phonological loop plays an important role in task switching. Until now, however, it has been unclear whether it is the maintenance of the task sequence or the retrieval of the task goal that requires phonological processing. In the present study, 60 participants (20 children, 20 adolescents, 20 young adults) performed three phonological working-memory tests before they switched between two tasks in a cue-present condition (random task sequence) and in a cue-absent condition (predictable task sequence). Results revealed that better phonological and central-executive working-memory performance predicted lower switch costs. In line with age-differentiation of cognitive abilities switching was less coupled with working memory in adults compared to children and adolescents. Interestingly, however, relations were only demonstrated in the cue-present but not in the cue-absent condition, indicating that it is more the retrieval of the task goal than the maintenance of the task sequence that requires the involvement of phonological processing.     

Phonological similarity effects in verbal complex span

Phonological similarity effects were used to assess the role of acoustic coding in verbal complex span, a processing-plus-storage measure found to correlate significantly with aspects of complex cognition. Three experiments demonstrated consistent effects of phonological similarity on listening span. These effects appeared relatively insensitive to manipulations of task materials (Experiment 1) and differences in processing task demands (Experiments 2 and 3). The results were interpreted as reflecting a significant role for the phonological loop in supporting verbal complex span and a multicomponent view of working memory, as tapped by these tests. Phonological similarity did not significantly interact with aspects of the tasks varied across Experiments 1 to 3, suggesting a relative robustness of the effect. However, variation in the phonological similarity effect sizes across Experiments 1 to 3 supports the suggestion that task demands and characteristics have the potential to disrupt the phonological similarity effect and, by implication, the reliance on a phonological code.     

Speech segmentation by statistical learning is supported by domain-general processes within working memory

The purpose of this study was to examine the extent to which working memory resources are recruited during statistical learning (SL). Participants were asked to identify novel words in an artificial speech stream where the transitional probabilities between syllables provided the only segmentation cue. Experiments 1 and 2 demonstrated that segmentation performance improved when the speech rate was slowed down, suggesting that SL is supported by some form of active processing or maintenance mechanism that operates more effectively under slower presentation rates. In Experiment 3 we investigated the nature of this mechanism by asking participants to perform a two-back task while listening to the speech stream. Half of the participants performed a two-back rhyme task designed to engage phonological processing, whereas the other half performed a comparable two-back task on un-nameable visual shapes. It was hypothesized that if SL is dependent only upon domain-specific processes (i.e., phonological rehearsal), the rhyme task should impair speech segmentation performance more than the shape task. However, the two loads were equally disruptive to learning, as they both eradicated the benefit provided by the slow rate. These results suggest that SL is supported by working-memory processes that rely on domain-general resources.     

Working memory, strategy execution, and strategy selection in mental arithmetic

A total of 72 participants estimated products of complex multiplications of two-digit operands (e.g., 63 × 78), using two strategies that differed in complexity. The simple strategy involved rounding both operands down to the closest decades (e.g., 60 × 70), whereas the complex strategy required rounding both operands up to the closest decades (e.g., 70 × 80). Participants accomplished this estimation task in two conditions: a no-load condition and a working-memory load condition in which executive components of working memory were taxed. The choice/no-choice method was used to obtain unbiased strategy execution and strategy selection data. Results showed that loading working-memory resources led participants to poorer strategy execution. Additionally, participants selected the simple strategy more often under working-memory load. We discuss the implications of the results to further our understanding of variations in strategy selection and execution, as well as our understanding of the impact of working-memory load on arithmetic performance and other cognitive domains.     

Working memory,strategy execution,and strategy selection in mental arithmetic

A total of 72 participants estimated products of complex multiplications of two-digit operands (e.g., 63 × 78), using two strategies that differed in complexity. The simple strategy involved rounding both operands down to the closest decades (e.g., 60 × 70), whereas the complex strategy required rounding both operands up to the closest decades (e.g., 70 × 80). Participants accomplished this estimation task in two conditions: a no-load condition and a working-memory load condition in which executive components of working memory were taxed. The choice/no-choice method was used to obtain unbiased strategy execution and strategy selection data. Results showed that loading working-memory resources led participants to poorer strategy execution. Additionally, participants selected the simple strategy more often under working-memory load. We discuss the implications of the results to further our understanding of variations in strategy selection and execution, as well as our understanding of the impact of working-memory load on arithmetic performance and other cognitive domains.     

Simultaneous attentional guidance by working-memory and selection history reveals two distinct sources of attention

Recent theories of attention have proposed that selection history is a separate, dissociable source of information that influences attention. The current study sought to investigate the simultaneous involvement of selection history and working-memory on attention during visual search. Experiments 1 and 2 used target feature probability to manipulate selection history and found significant effects of both working-memory and selection history, although working-memory dominated selection history when they cued different locations. Experiment 3 eliminated the contribution of voluntary refreshing of working-memory and replicated the main effects, although selection history became dominant. Using the same methodology, but with reduced probability cue validity, both effects were present in Experiment 4 and did not significantly differ in their contribution to attention. Effects of selection history and working-memory never interacted. These results suggest that selection history and working-memory are separate influences on attention and have little impact on each other. Theoretical implications for models of attention are discussed.     

Separate roles for executive and phonological components of working memory in mental arithmetic

A dual-task methodology was used to investigate the roles played by executive and phonological aspects of working memory in mental arithmetic. Experiment 1 showed that suppression of articulation impaired the ability to add a pair of briefly presented three-digit numbers. Suppression had no effect when the need to store temporarily was minimized by making the numbers visible throughout calculation. Experiment 2 showed that disrupting executive processes by requiring concurrent performance of a Trails task impaired the ability to add numbers that remained permanently visible. Performance on the Trails task deteriorated as the number of carry operations in the addition increased. Experiment 3 showed that this decline in Trails performance was not simply due to the extra time taken by carrying. These and other features of the results suggest that the carrying component of mental arithmetic places substantial demands on executive processes, whereas the need to retain problem information is met by the phonological loop. The results are consistent with an interpretation of executive processes according to which there is a limit on the capacity to inhibit strongly primed routine operations.     

Are there gender differences in verbal and visuospatial working-memory resources?

Whereas women generally outperform men in episodic-memory tasks, little is known as to how the genders compare with respect to basic working-memory operations. In reference to Baddeley's (1986) model, the present study searched for possible gender differences in terms of accuracy (but not speed) of working-memory processes. Men and women completed series of working-memory tasks respectively involving verbal and visuospatial information, as well as a double-span task involving both classes of information. Control measures included verbal fluency and mental rotation tasks in which gender differences are frequently obtained. In these tasks, the results showed several of the expected gender contrasts. However, men and women were not found to differ significantly in any type of working memory save in the double-span task where women surpassed men. The patterns of task intercorrelation were largely similar in both genders. Discussion emphasises the manifestation, based on the present exploration, of an almost identical working-memory architecture in men and women.     

Effects of problem size,operation, and working-memory span on simple-arithmetic strategies: differences between children and adults?

Adult's simple-arithmetic strategy use depends on problem-related characteristics, such as problem size and operation, and on individual-difference variables, such as working-memory span. The current study investigates (a) whether the effects of problem size, operation, and working-memory span on children's simple-arithmetic strategy use are equal to those observed in adults, and (b) how these effects emerge and change across age. To this end, simple-arithmetic performance measures and a working-memory span measure were obtained from 8-year-old, 10-year-old, and 12-year-old children. Results showed that the problem-size effect in children results from the same strategic performance differences as in adults (i.e., size-related differences in strategy selection, retrieval efficiency, and procedural efficiency). Operation-related effects in children were equal to those observed in adults as well, with more frequent retrieval use on multiplication, more efficient strategy execution in addition, and more pronounced changes in multiplication. Finally, the advantage of having a large working-memory span was also present in children. The differences and similarities across children's and adult's strategic performance and the relevance of arithmetic models are discussed.     

Isolating phonological components that increase tip-of-the-tongue resolution

Three experiments investigated the role of specific phonological components in priming tip-of-the-tongue (TOT) resolution. When in a TOT state, participants read a list of words that included phonological primes intermixed among unrelated words. The phonological primes contained either the same first letter as the target (Experiment 1), a single syllable (first, middle, or last) of the target (Experiment 2), or the first phoneme or first syllable of the target (Experiment 3). Reading first-letter primes in Experiment 1 did not help to resolve TOTs, whereas reading first-syllable primes significantly increased word retrieval in Experiment 2. Experiment 3 replicated the results of Experiments 1 and 2 using first-phoneme primes instead of first-letter primes and using two primes instead of three, although first-syllable priming occurred only for primes read silently. The results of these experiments support a transmission deficit model, where TOTs are caused by weak connections among phonological representations and can be resolved through internal or overt production of specific phonology.     

儿童早期工作记忆与数学学习的关系

以往研究认为工作记忆对数学学习很重要,但是以往工作记忆和早期数学学习的关系研究结果并不一致。本研究运用元分析的方法回顾了33篇独立研究,含307项相关系数作为效应值,总被试量为42423名平均年龄3~8岁的儿童,旨在探讨工作记忆的3个主成分PL(语音回路)、VSSP(视觉空间画板)、CE(中央执行)与数学学习不同方面之间的关系,以及样本年龄对工作记忆和数学学习相关程度的调节作用。结果显示:工作记忆与数学学习确实存在强相关,工作记忆子成分中,CE与数学学习平均相关的程度最强。并且,CE与数学学习不同方面之间的相关程度不存在显著差异,PL、VSSP与数运算的相关程度比数概念更强,存在显著差异。样本年龄对CE、PL与数学学习之间相关关系存在显著调节作用,对VSSP与数学学习之间的相关关系不存在显著调节作用。文献梳理还发现,以往研究对数学学习的考察,大都聚焦数概念、数运算的内容,未来研究需要关注几何与空间、测量等方面内容。     

How conscious experience and working memory interact

Active components of classical working memory are conscious, but traditional theory does not account for this fact. Global Workspace theory suggests that consciousness is needed to recruit unconscious specialized networks that carry out detailed working memory functions. The IDA model provides a fine-grained analysis of this process, specifically of two classical working-memory tasks, verbal rehearsal and the utilization of a visual image. In the process, new light is shed on the interactions between conscious and unconscious aspects of working memory.     

Interference between storage and processing in working memory: Feature overwriting,not similarity-based competition

Eight experiments with the complex span paradigm are presented to investigate why concurrent processing disrupts short-term retention. Increasing the pace of the processing task led to worse recall, supporting the hypothesis that the processing task distracts attention from maintenance operations. Neither phonological nor semantic similarity between memory items and processing-task material impaired memory. In contrast, the degree of phonological overlap between memory items and processing-task material affected recall negatively, supporting feature overwriting as one source of interference in the complex span paradigm. When compared directly, phonological overlap impaired memory, but similarity had a beneficial effect. These findings rule out response competition or confusion as a mechanism of interference between storage and processing.     

The nature of the syllabic neighbourhood effect in French

We investigated whether and how sublexical units such as phonological syllables mediate access to the lexicon in French visual word recognition. To do so, two lexical decision task (LDT) experiments examined the nature of the syllabic neighbourhood effect. In Experiments 1a and b, the number of higher frequency syllabic neighbours was manipulated while controlling for the first bigram. The results failed to show a pure syllabic neighbourhood effect. In Experiments 2a and b, syllabic neighbourhood and bigram frequency were factorially manipulated. The interaction showed that the syllabic neighbourhood effect was inhibitory when bigram frequency was high, whereas it was facilitatory when bigram frequency was low. Similar patterns of results were found in both the yes/no (Experiments 1a and 2a) and go/no-go LDTs (Experiments 1b and 2b), so varying task requirements of the lexical decision did not influence the effect. These findings are discussed in the context of parallel distributed processing and interactive-activation models, and suggest that orthographic redundancy properties contribute to the influence of phonological syllables.     

Verbal working memory and on-line syntactic processing: Evidence from self-paced listening

Two experiments investigated the relationship between performance on standard tests of verbal working-memory and the on-line construction of syntactic form. In Experiment 1, working-memory was measured in 100 college students on a version of the Daneman and Carpenter (1980) reading-span task, and online syntactic processing was assessed using a self-paced listening task with four sentence types. In Experiment 2, working-memory was measured in 48 college students on two versions of the reading-span task and two other tests of verbal working-memory, and on-line syntactic processing was assessed using the self-paced listening task with an additional sentence type. In both experiments, there was no relationship between working-memory capacity and the increase in processing time seen for the on-line construction of syntactic form for either syntactically more complex or syntactically simpler sentences. The results indicate that the capacity of the working-memory system that is measured by standard working-memory tests does not determine the efficiency of on-line syntactic processing. They are consistent with the view that the working-memory system used for parsing is at least partially separate from that measured by traditional measures of working-memory capacity.