Activation of number facts in bilinguals

Two experiments examined the effect of the presentation format of numbers—digits versus word format in the first and in the second languages of bilinguals—on mental arithmetic. Speed of number-fact retrieval and the presence of interference produced by numbers that were either numerically close to or associatively related to the correct answers of stored arithmetic problems (e.g., 2+5 and 7×8) were compared across formats. The verification of true problems was increasingly slower and less accurate from the digit condition to the second-language condition. Interference was produced by both types of incorrect answers in the digit and first-language conditions, whereas in the second-language condition, it was constrained to answers that were numerically close to correct answers. Together, the results suggest that the retrieval of arithmetic facts and the automatic spreading of activation within the network of numerical facts are not only language-sensitive, but format-sensitive in general.     

Language-specific memory for everyday arithmetic facts in Chinese-English bilinguals

The role of language in memory for arithmetic facts remains controversial. Here, we examined transfer of memory training for evidence that bilinguals may acquire language-specific memory stores for everyday arithmetic facts. Chinese-English bilingual adults (n = 32) were trained on different subsets of simple addition and multiplication problems. Each operation was trained in one language or the other. The subsequent test phase included all problems with addition and multiplication alternating across trials in two blocks, one in each language. Averaging over training language, the response time (RT) gains for trained problems relative to untrained problems were greater in the trained language than in the untrained language. Subsequent analysis showed that English training produced larger RT gains for trained problems relative to untrained problems in English at test relative to the untrained Chinese language. In contrast, there was no evidence with Chinese training that problem-specific RT gains differed between Chinese and the untrained English language. We propose that training in Chinese promoted a translation strategy for English arithmetic (particularly multiplication) that produced strong cross-language generalization of practice, whereas training in English strengthened relatively weak, English-language arithmetic memories and produced little generalization to Chinese (i.e., English training did not induce an English translation strategy for Chinese language trials). The results support the existence of language-specific strengthening of memory for everyday arithmetic facts.     

The representation of multiplication and division facts in memory

Recently, using a training paradigm, Campbell and Agnew (2009) observed cross-operation response time savings with nonidentical elements (e.g., practice 3 + 2, test 5 - 2) for addition and subtraction, showing that a single memory representation underlies addition and subtraction performance. Evidence for cross-operation savings between multiplication and division have been described frequently (e.g., Campbell, Fuchs-Lacelle, & Phenix, 2006) but they have always been attributed to a mediation strategy (reformulating a division problem as a multiplication problem, e.g., Campbell et al., 2006). Campbell and Agnew (2009) therefore concluded that there exists a fundamental difference between addition and subtraction on the one hand and multiplication and division on the other hand. However, our results suggest that retrieval savings between inverse multiplication and division problems can be observed. Even for small problems (solved by direct retrieval) practicing a division problem facilitated the corresponding multiplication problem and vice versa. These findings indicate that shared memory representations underlie multiplication and division retrieval. Hence, memory and learning processes do not seem to differ fundamentally between addition-subtraction and multiplication-division.     

Cross-situational consistency in recognition memory response bias

Individuals taking an old–new recognition memory test differ widely in their bias to respond “old,” ranging from strongly conservative to strongly liberal, even without any manipulation intended to affect bias. Kantner and Lindsay (2012) found stability of bias across study–test cycles, suggesting that bias is a cognitive trait. That consistency, however, could have arisen because participants perceived the two tests as being part of the same experiment in the same context. In the present study, we tested for stability across two recognition study–test procedures embedded in markedly different experiments, held weeks apart, that participants did not know were connected. Bias showed substantial cross-situational stability. Moreover, bias weakly predicted identifications on an eyewitness memory task and accuracy on a go–no-go task. Although we found little in the way of relationships between bias and five personality measures, these findings suggest that response bias is a stable and broadly influential characteristic of recognizers.     

Random number generation and working memory

We demonstrate the close relationship that exists between random sequence generation and working memory functioning. We clarify the nature of this link by examining the impact of concurrent requirements for random sequence response quality. Experiments 1A and 1B show that marking specific response choices for differential treatment, either by requiring an ancillary behaviour or by suppressing these choices from output, impairs overall sequence quality. Contrasting with previous findings, these distinct concurrent tasks have comparable effects. We show that disruption is found only when concurrent demand is high. Experiment 2 demonstrates that increasing the dynamic working memory load by requiring the ancillary response to change during the task leads to additional disruption of randomisation. The results extend and refine our understanding of the contribution of active maintenance of representations in random generation.     

Working memory and two-digit number processing

The processing of two-digit numbers in comparison tasks involves the activation and manipulation of magnitude information to decide which number is larger. The present study explored the role of different working memory (WM) components and skills in the processing of two-digit numbers by examining the unit–decade compatibility effect with Arabic digits and number words. In the study, the unit–decade compatibility effect and different WM components were evaluated. The results indicated that the unit–decade compatibility effect was associated to specific WM skills depending on the number format (Arabic digits and number words). We discussed the implications of these results for the decomposed view of two-digit numbers.     

Working memory and two-digit number processing

The processing of two-digit numbers in comparison tasks involves the activation and manipulation of magnitude information to decide which number is larger. The present study explored the role of different working memory (WM) components and skills in the processing of two-digit numbers by examining the unit-decade compatibility effect with Arabic digits and number words. In the study, the unit-decade compatibility effect and different WM components were evaluated. The results indicated that the unit-decade compatibility effect was associated to specific WM skills depending on the number format (Arabic digits and number words). We discussed the implications of these results for the decomposed view of two-digit numbers.     

Storage and retrieval of addition facts: The role of number comparison

It is proposed that arithmetical facts are organized in memory in terms of a principle that is unique to numbers—the cardinal magnitudes of the addends. This implies that sums such as 4 + 2 and 2 + 4 are represented, and searched for, in terms of the maximum and minimum addends. This in turn implies that a critical stage in solving an addition problem is deciding which addend is the larger. The COMP model of addition fact retrieval incorporates a comparison stage, as well as a retrieval stage and a pronunciation stage. Three tasks, using the same subjects, were designed to assess the contribution of these three stages to retrieving the answers to single-digit addition problems. Task 3 was the addition task, which examined whether reaction times (RTs) were explained by the model; Task 1 was a number naming task to assess the contribution of the pronunciation stage; Task 2 was a magnitude comparison task to assess the contribution, if any, of the comparison stage. A regression equation that included just expressions of these three stages was found to account for 71% of the variance. It is argued that the COMP model fits not only the adult RT data better than do alternatives, but also the evidence from development of additional skills.     

Inferring facts from fiction: reading correct and incorrect information affects memory for related information

People can acquire both true and false knowledge about the world from fictional stories. The present study explored whether the benefits and costs of learning about the world from fictional stories extend beyond memory for directly stated pieces of information. Of interest was whether readers would use correct and incorrect story references to make deductive inferences about related information in the story, and then integrate those inferences into their knowledge bases. Participants read stories containing correct, neutral, and misleading references to facts about the world; each reference could be combined with another reference that occurred in a later sentence to make a deductive inference. Later they answered general knowledge questions that tested for these deductive inferences. The results showed that participants generated and retained the deductive inferences regardless of whether the inferences were consistent or inconsistent with world knowledge, and irrespective of whether the references were placed consecutively in the text or separated by many sentences. Readers learn more than what is directly stated in stories; they use references to the real world to make both correct and incorrect inferences that are integrated into their knowledge bases.     

Long-term semantic memory versus contextual memory in unconscious number processing

Subjects classified visible 2-digit numbers as larger or smaller than 55. Target numbers were preceded by masked 2-digit primes that were either congruent (same relation to 55) or incongruent. Experiments 1 and 2 showed prime congruency effects for stimuli never included in the set of classified visible targets, indicating subliminal priming based on long-term semantic memory. Experiments 2 and 3 went further to demonstrate paradoxical unconscious priming effects resulting from task context. For example, after repeated practice classifying 73 as larger than 55, the novel masked prime 37 paradoxically facilitated the "larger" response. In these experiments task context could induce subjects to unconsciously process only the leftmost masked prime digit, only the rightmost digit, or both independently. Across 3 experiments, subliminal priming was governed by both task context and long-term semantic memory.     

The persistence of inferences in memory for younger and older adults: Remembering facts and believing inferences

Research shows that younger adults have difficulty forgetting inferences that they make after reading a passage, even if the information that the inferences are based on is later shown to be untrue. The present study examined the effects of these inferences on memory in the lab and tested whether older adults, like younger adults, are influenced by the lingering effects of false inferences. In addition, this study examined the nature of these inferences, by examining younger and older adults’ subjective experiences and confidence associated with factual recall and incorrect inference recall. The results showed that younger and older adults were equally susceptible to the continued influence of inferences. Both younger and older adults tended to remember facts from the stories but to believe their inferences, although confidence judgments did not differ for facts and inferences.     

The self-choice elaboration effects on incidental memory of Japanese historical facts

The subjects performed an orienting task involving 3 conditions, followed by unexpected tests which included free recall, name-matching and name-selec tion. Conditions were designed to force self-generated elaboration, self-choice elaboration, and experimenter-provided elaboration. In the self-generated elaboration condition, subjects were presented target sentences, e.g., Nobunaga ODA burned down ENRYAKUJI Temple, and asked to answer an elaborative interrogation, e.g., Why did Nobunaga ODA burn down ENRYAKUJI Temple? about each sentence. In the self-choice elaboration condition, subjects selected one of the alternative answers to an elaborative interrogation about each sentence. In the experimenter provided elaboration condition, subjects were presented an answer which they rated for congruity as the correct answer to the elaborative interrogation. In the free recall test, self generated elaboration led to better performance than the other two conditions for which no difference was observed. However, in the name-matching and name-selection tests, scores were better for self choice elaboration and self-generated elaboration than for experimenter-provided elaboration. These results were interpreted as demonstrating that self choice elaboration, in addition to self-generated elaboration, led to effective encoding in memory.     

The number and quality of representations in working memory

Flexible-resource theories characterize working memory as a flexible resource that can store either a large number of low-quality representations or a small number of high-quality representations. In contrast, limited-item theories propose that the number of items that can be stored in working memory is strictly limited and cannot be increased by decreasing the quality of the representations. We tested these fundamentally different conceptualizations of working memory capacity by determining whether observers could trade quality for quantity in working memory when given incentives to do so. We found no evidence that observers could increase the number of representations by decreasing their quality in working memory, but observers could make such a trade-off at earlier processing stages. Our results show that the capacity limit of working memory is best characterized as a limit on the number of items that can be stored and not as a limit on a finely divisible resource that simultaneously determines the number and quality of the representations.     

Tactual Performance Test: internal consistency reliability of the memory and location scores

Internal consistency reliabilities were computed for the Tactual Performance Test Memory and Location scores (N=602). After adjusting for unequal item difficulty, the reliabilities for Memory and Location were .69 and .79, respectively.     

Time and resource limits on working memory: cross-age consistency in counting span performance

This longitudinal study separated resource demand effects from those of retention interval in a counting span task among 100 children tested in grade 2 and again in grades 3 and 4. A last card large counting span condition had an equivalent memory load to a last card small, but the last card large required holding the count over a longer retention interval. In all three waves of assessment, the last card large condition was found to be less accurate than the last card small. A model predicting reading comprehension showed that age was a significant predictor when entered first accounting for 26% of the variance, but counting span accounted for a further 22% of the variance. Span at Wave 1 accounted for significant unique variance at Wave 2 and at Wave 3. Results were similar for math calculation with age accounting for 31% of the variance and counting span accounting for a further 34% of the variance. Span at Wave 1 explained unique variance in math at Wave 2 and at Wave 3.     

The memory failures of everyday questionnaire (MFE): internal consistency and reliability

The Memory Failures of Everyday Questionnaire (MFE) is one of the most widely-used instruments to assess memory failures in daily life. The original scale has nine response options, making it difficult to apply; we created a three-point scale (0-1-2) with response choices that make it easier to administer. We examined the two versions' equivalence in a sample of 193 participants between 19 and 64 years of age. The test-retest reliability and internal consistency of the version we propose were also computed in a sample of 113 people. Several indicators attest to the two forms' equivalence: the correlation between the items' means (r = .94; p < .001) and the order of the items' frequencies (r = .92; p < .001). However, the correlation between global scores on the two forms was not very high (r = .67; p < .001). The results indicate this new version has adequate reliability and internal consistency (r(xx) = .83; p < .001; alpha = .83; p < .001) equivalent to those of the MFE 1-9. The MFE 0-2 provides a brief, simple evaluation, so we recommend it for use in clinical practice as well as research.