Cultural variation in verbal versus spatial neuropsychological function across the life span.

Established culture-invariant measures are needed for cross-cultural assessment of verbal and visuospatial speed of processing and working memory across the life span. In this study, 32 younger and 32 older adults from China and from the United States were administered numerically based and spatially based measures of speed of processing and working memory. Chinese superiority on the numerically based tasks was found for younger adults. Age and increasing task demands diminished this cultural effect, as predicted by the framework proposed by D. C. Park, R. Nisbett, and T. Hedden (1999). However, the visuospatial measures of both working memory and speed of processing did not differ cross-culturally for either age group. The authors concluded that these visuospatial measures provide culture-invariant estimates of cognitive processes in East Asian and Western cultures, but that numerically based tasks show evidence of cultural and linguistic biases in performance levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Divergent trajectories in the aging mind: Changes in working memory for affective versus visual information with age.

Working memory mediates the short-term maintenance of information. Virtually all empirical research on working memory involves investigations of working memory for verbal and visual information. Whereas aging is typically associated with a deficit in working memory for these types of information, recent findings suggestive of relatively well-preserved long-term memory for emotional information in older adults raise questions about working memory for emotional material. This study examined age differences in working memory for emotional versus visual information. Findings demonstrate that, despite an age-related deficit for the latter, working memory for emotion was unimpaired. Further, older adults exhibited superior performance on positive relative to negative emotion trials, whereas their younger counterparts exhibited the opposite pattern. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The structure of working memory abilities across the adult life span.

The present study addresses three questions regarding age differences in working memory: (1) whether performance on complex span tasks decreases as a function of age at a faster rate than performance on simple span tasks; (2) whether spatial working memory decreases at a faster rate than verbal working memory; and (3) whether the structure of working memory abilities is different for different age groups. Adults, ages 20–89 (n = 388), performed three simple and three complex verbal span tasks and three simple and three complex spatial memory tasks. Performance on the spatial tasks decreased at faster rates as a function of age than performance on the verbal tasks, but within each domain, performance on complex and simple span tasks decreased at the same rates. Confirmatory factor analyses revealed that domain-differentiated models yielded better fits than models involving domain-general constructs, providing further evidence of the need to distinguish verbal and spatial working memory abilities. Regardless of which domain-differentiated model was examined, and despite the faster rates of decrease in the spatial domain, age group comparisons revealed that the factor structure of working memory abilities was highly similar in younger and older adults and showed no evidence of age-related dedifferentiation. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Working memory plasticity in old age: Practice gain, transfer, and maintenance.

Adult age differences in cognitive plasticity have been studied less often in working memory than in episodic memory. The authors investigated the effects of extensive working memory practice on performance improvement, transfer, and short-term maintenance of practice gains and transfer effects. Adults age 20-30 years and 70-80 years practiced a spatial working memory task with 2 levels of processing demands across 45 days for about 15 min per day. In both age groups and relative to age-matched, no-contact control groups, we found (a) substantial performance gains on the practiced task, (b) near transfer to a more demanding spatial n-back task and to numerical n-back tasks, and (c) 3-month maintenance of practice gains and near transfer effects, with decrements relative to postpractice performance among older but not younger adults. No evidence was found for far transfer to complex span tasks. The authors discuss neuronal mechanisms underlying adult age differences and similarities in patterns of plasticity and conclude that the potential of deliberate working memory practice as a tool for improving cognition in old age merits further exploration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A profile of neuropsychological deficits in alcoholic women.

Neuropsychological deficits, most notable in executive, visuospatial, and functions of gait and balance, are detectable in alcoholic men even after a month of sobriety. Less well established are the severity and profile of persisting deficits in alcoholic women. The authors used an extensive test battery to examine cognitive and motor functions in 43 alcoholic women who were sober, on average, for 3.6 months. Functions most severely affected in alcoholic women involved visuospatial and verbal and nonverbal working memory processes as well as gait and balance. Areas of relative sparing were executive functions, declarative memory, and upper-limb strength and speed. The authors found that lifetime alcohol consumption was related to impairment severity on Block Design (Wechsler Adult Intelligence Scale--Revised, D. Wechsler, 1981) and verbal and nonverbal working memory, suggesting a dose effect of alcohol abuse. The alcohol-related deficits in working memory, visuospatial, and balance implicate disruption of prefrontal, superior parietal, and cerebellar brain systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Moderate hypoglycemia impairs multiple memory functions in healthy adults.

The effects of acute insulin-induced hypoglycemia on short-term, delayed, and working memory were examined in healthy adults. A hyperinsulinemic glucose clamp was used to maintain arterialized blood glucose at either 4.5 (euglycemia) or 2.5 (hypoglycemia) mmol/L on 2 separate occasions in 16 healthy volunteers. Tests of immediate and delayed verbal memory, immediate and delayed visual memory, and working memory were administered during each experimental condition. All memory systems were impaired during acute hypoglycemia, with working memory and delayed memory being particularly susceptible. These findings are informative concerning the metabolic basis of adequate memory function and are of practical importance to people with insulin-treated diabetes, in whom hypoglycemia is common. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Study of Verbal Working Memory in Patients With Parkinson's Disease.

The authors examined the nature of the working memory deficit in persons with Parkinson's disease (PD). Three hypotheses were tested: a limited storage capacity, an impaired executive component, and a reduction of psychomotor speed. Verbal working memory was assessed in 14 PD patients without dementia and 14 matched control participants. Participants were administered a classical verbal span test, working memory tasks that required either updating or manipulation capacities, and motor and psychomotor speed tasks. Patients' performance was comparable to that of control participants on the verbal span test. However, results on the working memory tasks indicated a deficit in manipulation with normal updating capacities. Motor and psychomotor slowing were found in the patient group, but slowing could not fully account for the impairment observed in the manipulation task. Results indicated that there is a genuine but selective working memory impairment in patients with PD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The development of verbal memory in childhood and adolescence: Findings from the Munich Longitudinal Study.

The authors assessed developmental changes in verbal memory from the beginning of elementary school to late adolescence on the basis of data from the Munich Longitudinal Study. Major issues concern the stability of individual differences in strategy use as well as interrelationships among different components of verbal memory and the impact of educational context on verbal memory development. Long-term stability of strategic memory was low to moderate in late childhood and adolescence. Interrelations among the verbal memory components were also moderate and did not change much over time. Unexpectedly, no impact of educational context was found. Overall, individual differences in verbal memory performance develop very early in life and are relatively unaffected by differences in educational experiences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative and strategic components of episodic memory: A life-span dissociation.

The authors investigated the strategic component (i.e., elaboration and organization of episodic features) and the associative component (i.e., binding processes) of episodic memory and their interactions in 4 age groups (10-12, 13-15, 20-25, and 70-75 years of age). On the basis of behavioral and neural evidence, the authors hypothesized that the two components are functionally related but follow different life-span gradients. In a fully crossed design, age differences in recognition memory for single words versus word pairs (associative demand manipulation) were examined under instructions that emphasized item, pair, or elaborative-pair encoding (strategy manipulation). As predicted, the results showed that the strategic and associative components follow different life-span trajectories. Relative to younger adults, children's difficulties in episodic memory primarily reflected lower levels of strategic functioning. In contrast, older adults showed impairments in both strategic and associative components. The authors conclude that the comparison of strategic and associative components of episodic memory across the life span helps to delineate the two components' unique and interactive contributions to episodic memory performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Binding facilitates attention switching within working memory.

The authors investigated the units of selective attention within working memory. In Experiment 1, a group of participants kept 1 count and 1 location in working memory and updated them repeatedly in random order. Another group of participants were instructed to achieve the same goal by memorizing the verbal and spatial information in an integrative way as a moving digit. The behavioral data showed that switching attention between properties of an integrated working-memory item was faster than switching between respective properties of different items. Experiment 2 demonstrated that this switching facilitation cannot be simply ascribed to the different amount of working-memory items maintained by the two groups of participants. Finally, by adopting a pure verbal task in Experiment 3, the authors observed the same binding facilitation, with the possibility of "location-based selection" excluded. They summarize the observations of all 3 experiments in the study and suggest both a location- and object-based mechanism for attention selection in working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The structure of verbal abilities in young and older adults.

Four language sample measures as well as measures of vocabulary, verbal fluency, and memory span were obtained from a sample of young adults and a sample of older adults. Factor analysis was used to analyze the structure of the vocabulary, fluency, and span measures for each age group. Then an "extension" analysis was performed by using structural modeling techniques to determine how the language sample measures were related to the other measures. The measure of grammatical complexity was associated with measures of working memory including reading span and digit span. Two measures, sentence length in words and a measure of lexical diversity, were associated with the vocabulary measures. The fourth measure, propositional density, was associated with the fluency measures as a measure of processing efficiency. The structure of verbal abilities in young and older adults is somewhat different, suggesting age differences in processing efficiency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Short-term and working memory differences in language/learning disabled and normal adults

Fifteen adults who reported a childhood history of speech-language and/or learning disability (L/LD) were tested on two verbal memory tasks. Their performance on sentence repetition and reading span measures was compared with that of a matched control group who reported no childhood history of L/LD. Results indicated statistically significant group performance differences on both short-term and working memory tasks. This suggests that verbal memory difficulties may be a longterm component of L/LD.     

The Generality of Working Memory Capacity: A Latent-Variable Approach to Verbal and Visuospatial Memory Span and Reasoning.

A latent-variable study examined whether verbal and visuospatial working memory (WM) capacity measures reflect a primarily domain-general construct by testing 236 participants in 3 span tests each of verbal WM. visuospatial WM, verbal short-term memory (STM), and visuospatial STM. as well as in tests of verbal and spatial reasoning and general fluid intelligence (Gf). Confirmatory' factor analyses and structural equation models indicated that the WM tasks largely reflected a domain-general factor, whereas STM tasks, based on the same stimuli as the WM tasks, were much more domain specific. The WM construct was a strong predictor of Gf and a weaker predictor of domain-specific reasoning, and the reverse was true for the STM construct. The findings support a domain-general view of WM capacity, in which executive-attention processes drive the broad predictive utility of WM span measures, and domain-specific storage and rehearsal processes relate more strongly to domain-specific aspects of complex cognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Familiarity enhances visual working memory for faces.

Although it is intuitive that familiarity with complex visual objects should aid their preservation in visual working memory (WM), empirical evidence for this is lacking. This study used a conventional change-detection procedure to assess visual WM for unfamiliar and famous faces in healthy adults. Across experiments, faces were upright or inverted and a low- or high-load concurrent verbal WM task was administered to suppress contribution from verbal WM. Even with a high verbal memory load, visual WM performance was significantly better and capacity estimated as significantly greater for famous versus unfamiliar faces. Face inversion abolished this effect. Thus, neither strategic, explicit support from verbal WM nor low-level feature processing easily accounts for the observed benefit of high familiarity for visual WM. These results demonstrate that storage of items in visual WM can be enhanced if robust visual representations of them already exist in long-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Complex span versus updating tasks of working memory: The gap is not that deep.

How to best measure working memory capacity is an issue of ongoing debate. Besides established complex span tasks, which combine short-term memory demands with generally unrelated secondary tasks, there exists a set of paradigms characterized by continuous and simultaneous updating of several items in working memory, such as the n-back, memory updating, or alpha span tasks. With a latent variable analysis (N = 96) based on content-heterogeneous operationalizations of both task families, the authors found a latent correlation between a complex span factor and an updating factor that was not statistically different from unity (r = .96). Moreover, both factors predicted fluid intelligence (reasoning) equally well. The authors conclude that updating tasks measure working memory equally well as complex span tasks. Processes involved in building, maintaining, and updating arbitrary bindings may constitute the common working memory ability underlying performance on reasoning, complex span, and updating tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-referencing enhances memory specificity with age.

Self-referencing has been identified as an advantageous mnemonic strategy for young and older adults. However, little research has investigated the ways in which self-referencing may influence older adults' memory for details, which is typically impaired with age, beyond memory for the item itself. Experiment 1 assessed the effects of self- and other-referencing on memory for visually detailed pictures of objects in thirty-two young and thirty-two older adults. Results indicate that self- and close other-referencing similarly enhance general (item) and specific (detail) recognition for both young and older adults relative to the distant other condition. Experiment 2 extended these findings to source memory, with young and older adults encoding verbal information in self-referent, semantic, and structural conditions. Findings suggest that self-referencing provides an age-equivalent boost in general memory and specific memory for specific source details. We conclude that the mnemonic benefits of referencing the self extend to specific memory for visual and verbal information across the lifespan. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Memory performance and beliefs as a function of goal setting and aging.

This research examined the impact of goals on memory and memory beliefs. Older and younger adults completed memory beliefs questionnaires and list recall at baseline. After additional recall trials, the questionnaires were repeated. In Experiment 1, participants were assigned to low challenge or high challenge goals. In Experiment 2, moderate challenge goals were compared to control. In both studies, participants were given a specific goal based on their own performance and received positive feedback for memory gains. Both older and younger adults responded to the goals, showing improved performance across trials, with little change in the control condition. Memory beliefs changed in the moderate and low challenge goal conditions, showing more striking changes for the older groups. These results confirmed that self-regulatory processes related to goal setting can have considerable impact on memory across the adult life span. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Everyday memory compensation: The impact of cognitive reserve, subjective memory, and stress.

To determine the potential importance of several unexplored covariates of everyday memory compensation, the authors examined relations between responses on the Memory Compensation Questionnaire (a self-report measure of everyday memory compensation) and cognitive reserve (education and verbal IQ), subjective memory, and life stress in 66 older adults (mean age = 70.55 years). Key results indicated that compensation occurred in people (a) whose IQ level was greater than their education level (representing cognitive reserve “discordance”) but not in people whose IQ was commensurate with their education (representing cognitive reserve “concordance”); (b) who had greater perceived memory errors; and (c) who experienced heightened stress. Further, high-stress older adults compensated whether perceived memory errors were low or high, but low-stress older adults compensated only if they perceived high memory errors. Bootstrapped confidence intervals around model betas provided further support for estimate reliability. These results suggest boundary conditions for the concept of cognitive reserve, and highlight the importance of subjective memory and life stress for defining contexts in which compensation may occur. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive predictors of medical decision-making capacity in traumatic brain injury.

Objective: To identify cognitive predictors of medical decision-making capacity (MDC) in participants with moderate to severe traumatic brain injury (TBI). Participants: At baseline, participants were 34 adults with TBI and 20 healthy adults. At 6-month follow-up, participants were 24 adults with TBI and 20 healthy adults. Main Outcome Measures: Participants were administered the Capacity to Consent to Treatment Instrument (CCTI) and neuropsychological test measures. Multivariate cognitive predictor models were developed for CCTI consent abilities/standards (S) of understanding (S5); reasoning (S4); and appreciation (S3). Results: At baseline, short-term verbal memory and semantic fluency predicted TBI group performance on understanding (S5); short-term verbal memory and attention predicted performance on reasoning (S4); and working memory predicted performance on appreciation (S3). At 6 month follow-up, executive function, verbal processing speed, and working memory predicted TBI performance on understanding (S5); working memory and short-term memory predicted reasoning (S4); and basic executive functioning predicted appreciation (S3). Conclusions: Multiple cognitive functions are associated with acute impairment and partial recovery of MDC in patients with TBI. Short-term verbal memory predicted consent capacity of TBI participants at the time of acute inpatient hospitalization, while executive functioning and working memory predicted improved capacity at six-month follow-up. (PsycINFO Database Record (c) 2010 APA, all rights reserved)