Cognitive mediation of adult age differences in language performance.

Young (M?=?20 years) and old (M?=?68 years) adults completed language processing tasks, measures of working memory capacity (backward span and the n-back lag task), inhibitory efficiency (Stroop interference), and processing speed (color naming). Regression analyses revealed that each of the resource measures significantly predicted language performance and attenuated variance in language performance that would otherwise be attributed to age. When speed variance was entered into the equation first, the mediating influence of the inhibition and working memory measures remained significant. When speed and inhibition differences were controlled, the working memory measures could not reliably predict language performance. These results suggest that language performance differences may be fundamentally mediated by age differences in processing speed and inhibitory efficiency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociable properties of memory systems: Differences in the flexibility of declarative and nondeclarative knowledge.

Amnesic patients (n?=?8), who have severely impaired declarative memory, learned a probabilistic classification task at the same rate as normal subjects (n?=?16); but subsequently were impaired on transfer tests that required flexible use of their task knowledge. A second group of controls (n?=?20) rated the questions on the transfer tests according to whether the questions simply reinstated the training conditions or required flexible use of task knowledge. The amnesic patients tended to be impaired on the same items that were rated as requiring indirect or flexible use of knowledge. Thus, control subjects acquired declarative knowledge about the task that could be applied flexibly to the transfer tests. The nondeclarative memory available to amnesic patients was relatively inflexible and available only in conditions that reinstated the conditions of training. These findings show that declarative memory has different operating characteristics than nondeclarative memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age and working memory: The role of perceptual speed, the central executive, and the phonological loop.

In a study (N?=?61) comparing older (age range?=?60–80 years, M?=?67) and younger (age range?=?20-33 years, M?=?25) people, age deficits were observed in working memory, perceptual speed, and central executive functioning but not in phonological loop functioning. Controlling for age differences in central executive performance removed over 50% of the age-related variance in working memory span. However, controlling for perceptual speed removed all of the age-related variance in working memory span. In addition, age differences in central executive functioning were largely eliminated after controlling for age deficits in perceptual speed. These findings suggest that age differences in central executive functioning are primarily attributable to a general slowdown in the rate at which information is activated within the working memory system and that no specific deficits in the central executive occur as a consequence of aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Early reading acquisition and its relation to reading experience and ability 10 years later.

A group of 1st-graders who were administered a battery of reading tasks in a previous study were followed up as 11th graders. Ten years later, they were administered measures of exposure to print, reading comprehension, vocabulary, and general knowledge. First-grade reading ability was a strong predictor of all of the 11th-grade outcomes and remained so even when measures of cognitive ability were partialed out. First-grade reading ability (as well as 3rd- and 5th-grade ability) was reliably linked to exposure to print, as assessed in the 11th grade, even after 11th-grade reading comprehension ability was partialed out, indicating that the rapid acquisition of reading ability might well help develop the lifetime habit of reading, irrespective of the ultimate level of reading comprehension ability that the individual attains. Finally, individual differences in exposure to print were found to predict differences in the growth in reading comprehension ability throughout the elementary grades and thereafter. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impact of peripheral glucoregulation on memory.

Impaired glucoregulation is associated with neuropsychological deficits, particularly for tests that measure verbal declarative memory performance in older diabetic patients. The performances of 74 undergraduate students (mean age = 21 years) on several verbal declarative measures, including immediate and delayed paragraph recall, verbal free recall, and order reconstruction tasks, were correlated with glucoregulatory indices. The indices were obtained from glucose and insulin levels after a 75-g glucose load. In general, higher blood glucose levels were associated with poorer performance on all memory tests. Glucose ingestion did not interact with performance except on the most difficult task. Subjects with poorer glucoregulation showed higher evoked glucose and insulin, suggestive of a mild glucose intolerance accompanied by mild insulin insensitivity. Results suggest that poor peripheral glucoregulation has an impact on central nervous system functions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using children's literacy activities to predict growth in verbal cognitive skills: A longitudinal investigation.

Fourth-, fifth-, and sixth-grade children participated in a 2-year longitudinal study to determine the predictive validity of the Title Recognition Test (TRT) and the Author Recognition Test (ART), 2 checklist measures of individual differences in exposure to print. Multiple regression analyses confirmed the ability of the TRT to predict growth in receptive vocabulary, general information, spelling, sight vocabulary, verbal fluency, and reading comprehension even after controlling for age, recognition memory, and previous performance in the same cognitive competency area. The ART was found to be a less robust predictor. Although correlational, our results suggest that print exposure may be an independent contributor to cognitive growth in the verbal domain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging, cognitive resources, and declarative learning.

A battery of cognitive tasks designed to assess information-processing speed, working memory capability, and declarative learning was administered to a cross-sectional sample of 477 adults ranging in age from 17 to 86 years. Results showed significant age-related decrements in all three constructs. A variety of structural equation models was fit to the results. The preferred model on empirical and conceptual grounds was one that showed (a) working memory capability as the most important mediator of age effects in declarative learning; (b) working memory capability as the mediator for the effects of general processing speed on declarative learning; and (c) differentiation among verbal, numeric, and spatial processing speed and between verbal and spatial working memory capability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Investigation of functional working memory in the reading span test.

Two issues were investigated in 2 experiments: (1) the validity of a reading span test that combined a knowledge verification task with a secondary task of word memorization and (2) the hypothesis that word recall reflects the amount of working memory that is functional in reading. In Exp 1, the validity and reliability of the reading span measure were determined. In Exp 2, it was reasoned that if word recall reflected functional working memory in reading, then 2 results should be observed. The 1st predicted result was that prior exposure to sentences used in the reading span test would release working memory resources and improve word recall. The 2nd was that word recall, though correlated with general working memory and verbal knowledge measures, would add to these scores in predicting comprehension. Both sets of results were obtained, supporting the hypothesis that the reading span test measures functional working memory in reading. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Larger nondeclarative than declarative deficits in learning and memory in human aging.

This study used classical conditioning as a measure of nondeclarative learning and compared it with verbal learning as a declarative measure. Eighty participants were tested using 1 of 2 paradigms (400-ms and 750-ms delay) for eyeblink classical conditioning (EBCC) and the California Verbal Learning Test (CVLT). Large age differences were observed in the nondeclarative EBCC task, even in the 750-ms paradigm, which is more optimal for older adults. Age differences in the nondeclarative EBCC task were larger in the 400-ms paradigm and equal in the 750-ms paradigm to the magnitude of age differences in the declarative CVLT task. Partial correlations (removing the variance that was due to age) showed no relation between performance on the nondeclarative and declarative tasks. The results contradict the common assumption that, in the same participants, nondeclarative learning and memory are more resistant to the effects of aging than are declarative learning and memory and suggest that nondeclarative learning and memory are not unitary. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult age differences in working memory.

Active and passive measures of short-term memory over a large segment of the adult life span were compared. Two hundred twenty-eight volunteers, aged 30 to 99 years, performed the digit span forward and backward task, the Peterson-Peterson task, and a new working memory task in which active manipulation of information is emphasized. Age differences were slight for passive tasks. For the working memory task, significant declines were found between the ages of 60 to 69 and 70+ years. It is suggested that the age differences may be due to a decrease in the flexibility with which processing changes are made. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory is more sensitive than declarative memory to the acute effects of corticosteroids: A dose–response study in humans.

The effects of various doses (40 μg/kg/hr, 300 μg/kg/hr, 600 μg/kg/hr or placebo) of hydrocortisone on tasks assessing working and declarative memory function were measured in 4 groups of 10 young men. During the infusion, participants were given an item-recognition working memory task, a paired-associate declarative memory task, and a continuous performance task used to control possible concomitant effects of corticosteroids on vigilance. The results revealed significant acute effects of the highest dose of hydrocortisone on working memory function, without any significant effect on declarative memory function or arousal–vigilance performance. These results suggest that working memory is more sensitive than declarative memory to the acute elevations of corticosteroids, which could explain the detrimental effects of corticosteroids on acquisition and consolidation of information, as reported in the literature. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Improving group performance by training in individual problem solving.

This laboratory study investigated the group performance effects of an intervention to improve individual members use of task knowledge. Subjects were 169 managers (M age?=?40 years; 90% men and 10% women) and 207 MBA students (M age?=?28 years; 82% men and 18% women) working in 80 groups. The task was the Moon Survival problem. A bivariate, repeated measures analysis-of-variance statistical model was used. The intervention, based on suggestions by Maier (1970) and Janis and Mann (1977), upgraded both group resources (by 0.6 SD, pSD, p     

Short-term longitudinal change in cognitive performance in later life.

Changes in mean performance on memory, information processing, and intellectual ability tasks over a 3-yr period were examined. The sample consisted of 328 community-dwelling men and women (from an original sample of 484 individuals) aged 55–86 yrs. Ss completed tasks yielding measures of verbal processing time, working memory, implicit memory, vocabulary, verbal fluency, world knowledge, reading comprehension, word recall, and text recall. The results showed significant average decline on working memory, verbal fluency, and world knowledge. There were also interactions for 2 processing time measures and working memory, showing greater decline in the earlier-born cohort group than in the later-born cohort group. A step-down analysis revealed that covarying declines in other variables, including processing time, did not eliminate significant declines in working memory, verbal fluency, and world knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An investigation of the role of working memory in procedural skill acquisition.

On the basis of the ACT* production system theory of skill acquisition (Anderson, 1983a, 1987), I generated predictions concerning the role of two proposed classes of working-memory limitations in procedural learning. Individual differences analyses of a laboratory procedural learning task tested these predictions. As hypothesized, measures of controlled attention in working memory predicted initial declarative rule acquisition and proceduralization, and measures of automatic activation in working memory predicted indexes of later production composition and strengthening. Results supported a distinction between two working-memory capacity constructs that impose unique limits on processes of skill acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Deciding where knowledge comes from depends on where you look.

The purpose of this investigation was to replicate the findings of K. E. Stanovich and A. E. Cunningham (1993) concerning the antecedents of declarative knowledge, using different measures of general ability and TV exposure. In addition, the authors were interested in the relationship between epistemological knowledge and these measures. Ninety-seven introductory psychology students participated. Results showed that measures of both general ability and TV exposure exhibited a stronger relationship to declarative knowledge than that found by K. E. Stanovich and A. E. Cunningham. These differences in results concerning TV exposure were explained by suggesting the possibility that watching educational TV increases literacy whereas watching noneducational TV may actually limit it. The epistemological beliefs of simple and certain knowledge were statistically related to composites of knowledge, ability, and both types of exposure. (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)     

Assessment of working memory in six- and seven-year-old children.

Using cognitive methods to fractionate functionally distinct aspects of short-term memory, a test battery was designed to tap the A. D. Baddeley and G. Hitch (1974) model of working memory. The battery was administered to 87 children aged 6 and 7 years; other standardized attainment measures were obtained for a subgroup of the children concurrently and 1 year later. Correlations between subtest scores indicated high construct validity for the central executive and phonological loop measures, although not for the visuospatial measures. Central executive scores shared unique associations with performance on the vocabulary, literacy, and arithmetic tests, whereas phonological loop scores shared specific associations with vocabulary knowledge only. The substantial internal and external validity of the test battery establishes its suitability for guiding detailed theoretical analyses of working memory function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Where does knowledge come from? Specific associations between print exposure and information acquisition.

In a study of 268 college students, measures of exposure to print predicted individual differences in knowledge in a variety of domains even after individual differences on 4 indicators of general ability (high school GPA, Raven Advanced Progressive Matrices, Nelson-Denny Reading Test—Comprehension subtest, and a mathematics ability test) had been statistically controlled. Although correlational, results suggest that print exposure is an independent contributor to the acquisition of content knowledge. The data challenge the view that knowledge acquisition is determined only by the efficiency of cognitive components that encode and store information. Instead, the results indicate that differences in exposure to information, particularly written sources of information, is a significant contributor to differences in knowledge across individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and individual differences in the development of skilled memory search performance.

We examined individual differences in measures of multiple intellectual abilities and performance on a pure memory search task over 5 experimental sessions. Old (n?=?104) and young (n?=?97) participants showed expected patterns of substantial improvement in memory search intercepts and slopes in consistently mapped (CM) conditions, relative to varied mapping (VM) conditions. Initial (unskilled) CM and VM memory search was highly correlated with a Semantic Memory Access Speed factor and moderately correlated with General Intelligence. Structural equation models showed that measures of Semantic Memory Access remained a strong predictor of skilled CM search performance in both age groups despite individual differences in CM memory search performance changes. These results indicate qualitative differences in the nature of automaticity between memory search and visual search and suggest age invariance in the mechanisms determining automaticity in memory search. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predicting conversion to dementia of the Alzheimer’s type in a healthy control sample: The power of errors in stroop color naming.

In the present study, we investigated which cognitive functions in older adults at Time A are predictive of conversion to dementia of the Alzheimer’s type (DAT) at Time B. Forty-seven healthy individuals were initially tested in 1992–1994 on a trial-by-trial computerized Stroop task along with a battery of psychometric measures that tap general knowledge, declarative memory, visual–spatial processing, and processing speed. Twelve of these individuals subsequently developed DAT. The errors on the color incongruent trials (along with the difference between congruent and incongruent trials) and changes in the reaction time distributions were the strongest predictors of conversion to DAT, consistent with recent arguments regarding the sensitivity of these measures. Notably in the psychometric measures, there was little evidence of a difference in declarative memory between converters and nonconverters, but there was some evidence of changes in visual-spatial processing. Discussion focuses on the accumulating evidence suggesting a role of attentional control mechanisms as an early marker for the transition from healthy cognitive aging to DAT. (PsycINFO Database Record (c) 2010 APA, all rights reserved)