Age differences and similarities in patterns of cerebral hemispheric asymmetry.

Younger (M age?=?20.4 years) and older (M age?=?70.7 years) adults participated in 3 visual half-field experiments. These were designed to examine specific aspects of hemispheric asymmetry: (a) hemispheric dominance for phonetic–linguistic processing (as measured by identification of nonword trigrams), (b) hemispheric differences in trigram processing strategy, (c) characteristic perceptual biases thought to reflect hemispheric arousal asymmetries, and (d) hemispheric dominance for processing emotions shown on faces. Patterns of left–right asymmetries were comparable for older and younger participants, and intercorrelations among the various measures of asymmetry were similar for both groups. In view of the present results, it seems unlikely that changes in hemispheric asymmetry contribute significantly to age-related changes in cognitive functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of aging and task difficulty on divided attention performance.

We report two experiments that compare the performance of young and older adults on perceptual-motor tasks involving division of attention. Previous studies have shown older people to be especially penalized by divided attention situations, but the generality of this finding was recently challenged by Somberg and Salthouse (1982). The present study was conducted to investigate the possibility that age differences in dual-task performance are amplified by an increase in the difficulty of the constituent tasks, where difficulty was manipulated by varying the central, cognitive nature of the tasks (Experiment 1) or the degree of choice involved (Experiment 2). With the present tasks, strong evidence was found for an age-related decrement in divided attention performance. Contrary to our original expectations, however, it does not seem that division of attention presents some especial difficulty to older people. Rather, division of attention is one of several equivalent ways to increase overall task complexity. In turn, age differences are exaggerated as tasks are made more complex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Understanding verbal fluency in healthy aging, Alzheimer's disease, and Parkinson's disease.

Objective: Verbal fluency measures are frequently part of batteries designed to assess executive function (EF), but are also used to assess semantic processing ability or word knowledge. The goal of the present study was to identify the cognitive components underlying fluency performance. Method: Healthy young and older adults, adults with Parkinson's disease, and adults with Alzheimer's disease performed letter, category, and action fluency tests. Performance was assessed in terms of number of items generated, clustering, and the time course of output. A series of neuropsychological assessments were also administered to index verbal ability, working memory, EF, and processing speed as correlates of fluency performance. Results: Findings indicated that regardless of the particular performance measure, young adults performed the best and adults with Alzheimer's disease performed most poorly, with healthy older adults and adults with Parkinson's disease performing at intermediate levels. The exception was the action fluency task, where adults with Parkinson's disease performed most poorly. The time course of fluency performance was characterized in terms of slope and intercept parameters and related to neuropsychological constructs. Speed of processing was found to be the best predictor of performance, rather than the efficiency of EF or semantic knowledge. Conclusions: Together, these findings demonstrate that the pattern of fluency performance looks generally the same regardless of how performance is measured. In addition, the primary role of processing speed in performance suggests that the use of fluency tasks as measures of EF or verbal ability warrants reexamination. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Aging and negative priming in a location suppression task: The long and the short of it.

The role of temporal parameters in aging and inhibitory function was examined using negative priming (NP) and repetition priming (RP) in a task involving a series of visually presented prime-probe sets; responses were made on the basis of the location of a target stimulus. Preparatory intervals (PI) preceding prime-probe sets were 3,000 ms or 1,500 ms. The longer PI resulted in less NP in older adults than did the shorter PI. Further analyses suggest that older adults may be less prepared to inhibit the distractor following the longer PI. The longer PI also produced more RP than did the shorter PI for both age groups, indicating a greater emphasis on facilitatory processes in this condition. In addition, evidence was obtained to suggest that an inverse relationship between NP and RP exists for both young and old adults. These data suggest that individuals or task conditions may emphasize either facilitation or inhibition in selection. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The role of visual attention in predicting driving impairment in older adults.

This study evaluated the role of visual attention (as measured by the DriverScan change detection task and the Useful Field of View Test [UFOV]) in the prediction of driving impairment in 155 adults between the ages of 63 and 87. In contrast to previous research, participants were not oversampled for visual impairment or history of automobile accidents. Although a history of automobile accidents within the past 3 years could not be predicted using any variable, driving performance in a low-fidelity simulator could be significantly predicted by performance in the change detection task and by the divided and selection attention subtests of the UFOV in structural equation models. The sensitivity and specificity of each measure in identifying at-risk drivers were also evaluated with receiver operating characteristic curves. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eye movements of young and older adults while reading with distraction.

The authors used eye-tracking technology to examine young and older adults' online performance in the reading in distraction paradigm. Participants read target sentences and answered comprehension questions following each sentence. In some sentences, single-word distracters were presented in either italic or red font. Distracters could be related or unrelated to the target text. Online measures, including probability of fixation, fixation duration, and number of fixations to distracting text, revealed no age differences in text processing. However, young adults did have an advantage over older adults in overall reading time and text comprehension. These results provide no support for an inhibition deficit account of age differences in the reading in distraction paradigm, but are consistent with J. Dywan and W. E. Murphy's (1996) suggestion that older adults are less able than the young to distinguish target and distracter information held in working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibition and aging: Similarities between younger and older adults as revealed by the processing of unattended auditory information.

The ability to selectively attend to an auditory stimulus appears to decline with age and may result from losses in the ability to inhibit the processing of irrelevant stimuli (i.e., the inhibitory deficit hypothesis; L. Hasher & R. T. Zacks, 1988). It is also possible that declines in the ability to selectively attend are a result of age-related hearing losses. Three experiments examined whether older and younger adults differed in their ability to inhibit the processing of distracting stimuli when the listening situation was adjusted to correct for individual differences in hearing. In all 3 experiments, younger and older adults were equally affected by irrelevant stimuli, unattended stimuli, or both. The implications for auditory attention research and for possible differences between auditory and visual processing are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contributions of surface and conceptual information to performance on implicit and explicit memory tasks.

Four experiments examined the effects of perceptual and conceptual processing operations on 2 implicit and 2 explicit memory tasks. Results show an advantage of visual over auditory presentation for word-fragment completion, word-stem completion, and word-stem cued recall; there was no such advantage in recognition memory. Conceptual processing had no effect on the implicit tasks, a small effect on word-stem cued recall, and a large effect on recognition. It is concluded that there is no necessary trade-off between the 2 types of information. Speculatively, the use of perceptual information may be all or none and relatively automatic, whereas the use of conceptual information appears to be graded and more under conscious control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging, selective attention, and inhibitory processes: A psychophysiological approach.

Investigated the efficiency with which younger and older adults allocate attention to relevant and irrelevant stimuli. The model of attention guiding this research links the orienting response with the allocation of attention and habituation with the inhibition of the allocation of attention. The authors adapted a paradigm developed by W. G. Iacono and D. T. Lykken (1983) in which Ss are instructed unambiguously either to attend or to ignore a series of innocuous tones, and the skin conductance orienting response elicited by each tone is measured. Results revealed that young Ss instructed to ignore the tones habituated more quickly than did those instructed to attend to the tones. However, older adults exhibited nondifferential orienting across the 2 instruction conditions. These results suggest an age-related deficit in the ability to inhibit attention to irrelevant stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in recall and recognition.

An experiment is reported in which young and elderly adults performed cued-recall and recognition tests while carrying out a choice reaction-time task. An analysis of covariance, with recognition performance as the covariate, showed a reliable age decrement in recall. It was therefore concluded that older people perform more poorly on recall tasks than they do on recognition tasks. Performance on the secondary (reaction time) task showed that recall was associated with greater resource "costs" than was recognition and that this effect was amplified by increasing age. The results are in line with the suggestion that recall requires more processing resources than does recognition and that such resources are depleted as people grow older. (PsycINFO Database Record (c) 2010 APA, all rights reserved)