Working Memory Capacity Test Research Articles

A Prospective Study of the Physiological and Neurobehavioral Effects of Ramadan Fasting in Preteen and Teenage Boys

BackgroundIntermittent fasting during the month of Ramadan, although not obligatory, is commonly practiced by Muslim children. ObjectiveOur aim was to describe the effects of Ramadan fasting on various physiological and neurobehavioral measures in preteen and teenaged boys. DesignWe conduced a prospective cohort study during Ramadan, observed from August 9 to September 11, 2010. ParticipantsEighteen healthy Muslim boys (mean age±standard deviation 12.6±1.5 years) were recruited and assessed before, during (1st and 4th weeks), and after Ramadan. Subjects were classified as preteens (aged 9 to 12 years) or teens (aged 13 to 15 years). InterventionOn each clinic visit, participants completed a match-to-sample test, a spatial planning and working memory task, and a working memory capacity test using the Cambridge Neuropsychological Test Automated Battery. Participants were also assessed for their sleep patterns, daily energy expenditure, and dietary intake. Body composition was determined using a dual-energy x-ray scan. Complete blood count, lipid profile analysis, and iron indices were conducted. Main outcome measuresWe measured morphologic, metabolic, and neurobehavioral parameters. Statistical analysesA linear mixed model was used to assess changes in outcome measures. Post hoc pairwise comparisons were performed as necessary with Bonferroni adjustment. ResultsWithin 1 week of fasting, there was a drop in body fat only in preteens (P=0.001). Reported fat (P=0.004) and protein intake (P=0.037) was higher during Ramadan, but energy expenditure did not change. By the end of Ramadan, there was a significant reduction in hemoglobin (mean±standard error −0.48±0.4 mmol/L) and serum iron (−25.7±31.8 μg/dL [−4.6±5.7 μmol/L]) levels. During week 4, total sleep duration decreased by 1.8 hours. At week 4, performance on the spatial planning and working memory task and working memory capacity test increased significantly (P=0.002), while match-to-sample test performance declined in preteens only (P=0.045). ConclusionsRamadan fasting was associated with significant changes in body composition, dietary intake, and sleep patterns. Reductions in attention and iron indices were observed in preteens only.

The Effects of Implicit and Explicit Instruction on Foreign Language Learners’ Working Memory Capacity and L2 Grammatical Knowledge

This study investigated the role of implicit and explicit grammar instruction on expanding working memory capacity (WMC) and improving L2 grammatical knowledge. The participants were 30 L2 learners equally divided into two experimental classes. Before the treatment, a grammar pretest was used to measure their grammatical knowledge, and three tests (Forward Digit Span Test, Paired Associates Test, Operation Span Test) were used to measure their WMC. During the treatment, the explicit group studied grammar using the guided discovery, text-based teaching, and explicit feedback techniques, and the implicit group did so using textual enhancement, input flood, and implicit feedback techniques. At the end of the experiment, the same grammar test and WMC tests were used as posttests to check the effects of the treatments. The results showed that the implicit group had significantly outperformed the explicit group on WMC tests, while no such difference was observed between their grammar posttest scores.

The magical numbers 7 and 4 are resistant to the Flynn effect: No evidence for increases in forward or backward recall across 85 years of data

A substantial amount of empirical research suggests that cognitive ability test scores are increasing by approximately three IQ points per decade. The effect, referred to as the Flynn effect, has been found to be more substantial on measures of fluid intelligence, a construct known to be substantially correlated with memory span. Miller (1956) suggested that the typical short-term memory capacity (STMC) of an adult is seven, plus or minus two objects. Cowan (2005) suggested that the typical working memory capacity (WMC) of an adult is four, plus or minus one object. However, the possibility that both STMC and WMC test scores may be increasing across time, in line with the Flynn effect, does not appear to have been tested comprehensively yet. Based on Digit Span Forward (DSF) and Digit Span Backward (DSB) adult test scores across 85years of data (respective Ns of 7,077 and 6,841), the mean adult verbal STMC was estimated at 6.56 (±2.39), and the mean adult verbal WMC was estimated at 4.88 (±2.58). No increasing trend in the STMC or WMC test scores was observed from 1923 to 2008, suggesting that these two cognitive processes are unaffected by the Flynn effect. Consequently, if the Flynn effect is occurring, it would appear to be a phenomenon that is completely independent of STMC and WMC, which may be surprising, given the close correspondence between WMC and fluid intelligence.

Correlates and consequences of status and change in intellectual engagement

Self-reports of Intellectual Engagement (IE) focus on pleasure and enjoyment of intellectual activities. IE might be causal for knowledge loaded ability constructs. Available evidence on IE is usually correlational but longitudinal studies are better suited to pursue these research questions. 112 9th grade students participated in a two year intensive longitudinal study. Students worked on educational tests for Maths and German (local language), and Working Memory Capacity tests during the longitudinal phase. Additionally we administered measures of IE and recorded school grades repeatedly. Fluid and crystallized intelligence were measured at pre- and posttest. We will report about individual differences in status and change in IE and how both are related to proximal and distal ability and achievement criteria. Overall the results show only weak relations of status and change in IE and learning outcomes. We attribute this lack of relations to missing degrees of freedom in students learning behaviour.

Efl speech production: exploring the relationship between working memory capacity and profciency level

The present study explores the relationship between working memory capacity (WMC) and proficiency level in EFL 1 speech production. Forty-one participants performed two WMC tests – the Speaking Span Test in L1 and in L2. The statistical analysis indicated both a variation on WMC scores in L2 as a function of proficiency as well as a difference between WMC scores in L1 and in L2. Findings are explained mainly in respect to the interplay between automatic and controlled processes on memory retrieval and on the development of L2 proficiency.

Effect of Relaxation Training on Working Memory Capacity and Academic Achievement in Adolescents

In an experimental study 40 girl students of 7th grade were selected using random cluster sampling from one middle school in Tehran and divided into test and control groups by random assignment. Initially they were assessed by working memory capacity test (Daneman & Carpenter, 1980). Then, the test group through 12 educational sessions (one hour sessions, 3 sessions per week) was taught relaxation techniques, and it is noteworthy that no education was given to a control group. Upon completion of educational sessions, both test and control groups were assessed again with the working memory capacity test. In the case of the academic achievement, the Grade Point Average (GPA) of the first semester for pre-test and the GPA of the second semester for post-test were used. Multivariate analysis of covariance showed that relaxation training increase working memory capacity and its components, storage and processing, and academic achievement. Therefore, relaxation training is a useful technique for student progress.

The role of mind-wandering in measurements of general aptitude.

Tests of working memory capacity (WMC) and fluid intelligence (gF) are thought to capture variability in a crucial cognitive capacity that is broadly predictive of success, yet pinpointing the exact nature of this capacity is an area of ongoing controversy. We propose that mind-wandering is associated with performance on tests of WMC and gF, thereby partially explaining both the reliable correlations between these tests and their broad predictive utility. Existing evidence indicates that both WMC and gF are correlated with performance on tasks of attention, yet more decisive evidence requires an assessment of the role of attention and, in particular, mind-wandering during performance of these tests. Four studies employing complementary methodological designs embedded thought sampling into tests of general aptitude and determined that mind-wandering was consistently associated with worse performance on these measures. Collectively, these studies implicate the capacity to avoid mind-wandering during demanding tasks as a potentially important source of success on measures of general aptitude, while also raising important questions about whether the previously documented relationship between WMC and mind-wandering can be exclusively attributed to executive failures preceding mind-wandering (McVay & Kane, 2010b).

Acceptance of Background Noise, Working Memory Capacity, and Auditory Evoked Potentials in Subjects with Normal Hearing

The acceptable noise level (ANL) test is a method for quantifying the amount of background noise that subjects accept when listening to speech. Large variations in ANL have been seen between normal-hearing subjects and between studies of normal-hearing subjects, but few explanatory variables have been identified. To explore a possible relationship between a Swedish version of the ANL test, working memory capacity (WMC), and auditory evoked potentials (AEPs). ANL, WMC, and AEP were tested in a counterbalanced order across subjects. Twenty-one normal-hearing subjects participated in the study (14 females and 7 males; aged 20-39 yr with an average of 25.7 yr). Reported data consists of age, pure-tone average (PTA), most comfortable level (MCL), background noise level (BNL), ANL (i.e., MCL - BNL), AEP latencies, AEP amplitudes, and WMC. Spearman's rank correlation coefficient was calculated between the collected variables to investigate associations. A principal component analysis (PCA) with Varimax rotation was conducted on the collected variables to explore underlying factors and estimate interactions between the tested variables. Subjects were also pooled into two groups depending on their results on the WMC test, one group with a score lower than the average and one with a score higher than the average. Comparisons between these two groups were made using the Mann-Whitney U-test with Bonferroni correction for multiple comparisons. A negative association was found between ANL and WMC but not between AEP and ANL or WMC. Furthermore, ANL is derived from MCL and BNL, and a significant positive association was found between BNL and WMC. However, no significant associations were seen between AEP latencies and amplitudes and the demographic variables, MCL, and BNL. The PCA identified two underlying factors: One that contained MCL, BNL, ANL, and WMC and another that contained latency for wave Na and amplitudes for waves V and Na-Pa. Using the variables in the first factor, the findings were further explored by pooling the subjects into two groups according to their WMC (WMClow and WMChigh). It was found that the WMClow had significantly poorer BNL than the WMChigh. The findings suggest that there is a strong relationship between BNL and WMC, while the association between MCL, ANL, and WMC seems less clear-cut.

The Influence of Semantically Related and Unrelated Text Cues on the Intelligibility of Sentences in Noise

In two experiments with different subject groups, we explored the relationship between semantic context and intelligibility by examining the influence of visually presented, semantically related, and unrelated three-word text cues on perception of spoken sentences in stationary noise across a range of speech-to-noise ratios (SNRs). In addition, in Experiment (Exp) 2, we explored the relationship between individual differences in cognitive factors and the effect of the cues on speech intelligibility. In Exp 1, cues had been generated by participants themselves in a previous test session (own) or by someone else (alien). These cues were either appropriate for that sentence (match) or for a different sentence (mismatch). A condition with nonword cues, generated by the experimenter, served as a control. Experimental sentences were presented at three SNRs (dB SNR) corresponding to the entirely correct repetition of 29%, 50%, or 71% of sentences (speech reception thresholds; SRTs). In Exp 2, semantically matching or mismatching cues and nonword cues were presented before sentences at SNRs corresponding to SRTs of 16% and 29%. The participants in Exp 2 also performed tests of verbal working memory capacity and the ability to read partially masked text. In Exp 1, matching cues improved perception relative to the nonword and mismatching cues, with largest benefits at the SNR corresponding to 29% performance in the SRT task. Mismatching cues did not impair speech perception relative to the nonword cue condition, and no difference in the effect of own and alien matching cues was observed. In Exp 2, matching cues improved speech perception as measured using both the percentage of correctly reported words and the percentage of entirely correctly reported sentences. Mismatching cues reduced the percentage of repeated words (but not the sentence-based scores) compared with the nonword cue condition. Working memory capacity and ability to read partly masked sentences were positively associated with the number of sentences repeated entirely correctly in the mismatch condition at the 29% SNR. In difficult listening conditions, both relevant and irrelevant semantic context can influence speech perception in noise. High working memory capacity and good linguistic skills are associated with a greater ability to inhibit irrelevant context when uncued sentence intelligibility is around 29% correct.

Working Memory Capacity is Decreased in Sleep-Deprived Internal Medicine Residents

Concerns about medical errors due to sleep deprivation during residency training led the Accreditation Council for Graduate Medical Education to mandate reductions in work schedules. Although call rotations with extended shifts continue, effects on resident sleep-wake times and working memory capacity (WMC) have not been investigated. The objective of this study was to measure effects of call rotations on sleep-wake times and WMC in internal medicine residents. During 2 months of an internal medicine training program adhering to ACGME work-hour restrictions (between April 2006 and June 2007), residents completed daily WMC tests, wore actigraphy watches, and logged their sleep hours. This observational study was conducted during a call month requiring 30-hour call rotations every fourth night, whereas the noncall month, which allowed sleep/wake cycle freedom, was used as the control. Sleep hours per night and WMC testing. Thirty-nine residents completing the study had less sleep per night during their call month (6.4 vs 7.3 h per night noncall, p < 0.001) and sleep per night varied from 3.7 to 10.1 hours. Call rotation caused greater self-assessed sleepiness and reduced WMC recall scores (-2.6/test, p < 0.05), and more math errors occurred when on call (+1.07/test, p < 0.04). Full recovery of WMC did not occur until the fourth day after call. On-call rotation on the first month had a confounding detrimental effect on WMC. A month of call rotations reduced overall sleep per night; sleep hours per night were variable, and WMC was adversely affected. Decreased WMC could explain impaired judgment during sleep deprivation, although clinical error rates were not evaluated.

Working memory capacity can be improved by expressive writing: A randomized experiment in a Japanese sample

This study examined the influence of expressive writing on working memory capacity (WMC), a component of executive function. Japanese undergraduates (N=104) were individually tested across six separate experimental sessions (baseline, three writing, and two follow-up sessions at 1 and 5 weeks). Participants were randomly assigned to write about a traumatic experience, their best possible future selves (BPS), or a trivial topic for 20 minutes. WMC tests were completed at baseline and follow-ups. Results indicate that expressive writing about traumatic experience can improve WMC at 5 weeks after writing, but that writing about BPS or trivial topics has no effect on WMC.

A Comparison of Broad Versus Deep Auditory Menu Structures

The primary purpose of this experiment was to gain a greater understanding of the utilization of working memory when interacting with a speech-enabled interactive voice response (IVR) system. A widely promoted guideline advises limiting IVR menus to five or fewer items because of constraints of the human memory system, commonly citing Miller's (1956) paper. The authors argue that Miller's paper does not, in fact, support this guideline. Furthermore, applying modern theories of working memory leads to the opposite conclusion--that reducing menu length by creating a deeper structure is actually more demanding of users' working memories and leads to poorer performance and satisfaction. Participants took a working memory capacity test and then attempted to complete a series of e-mail tasks using one of two IVR designs (functionally equivalent, but one with a broad menu structure and the other with a deep structure). Users of the broad-structure IVR performed better and were more satisfied than users of the deep-structure IVR. Furthermore, this effect was more pronounced for those with low working memory capacity. Results indicate that creating a deeper structure is more demanding of working memory resource than the alternative of longer, shallower menus. This experiment has important practical implications for all systems with auditory menus (particularly IVRs) because it provides empirical evidence refuting a widely promoted design practice.