Biomedical subjects

A A Hartley

Publications and source records attributed to A A Hartley.

At least 19 recordsLinked to original sources

PubMed2001

Is the dissociability of working memory systems for name identity, visual-object identity, and spatial location maintained in old age?

The dissociability of working memory for name identity (verbal information), visual objects, and spatial location was explored in 3 experiments. Consistent with previous results, the 3 working memory systems were dissociable in younger adults. Both younger and older adults showed involvement of name identity in an object identity task, and older adults showed this involvement in a spatial memory task. Results were interpreted as showing that the systems are generally separable but that involvement of 1 with another is possible and more likely in older adults. A 4th, correlational study showed that there is generalized decline in working memory systems in old age, with the age differences in memory mediated to a moderate extent by age-related differences in speed of processing. It was speculated that the specific, possibly strategic changes are independent of and take place against a backdrop of generalized loss of nervous system integrity.

Acoustic Stimulation↗

PubMed2001

Age differences in dual-task interference are localized to response-generation processes.

Dual-task differences in younger and older adults were explored by presenting 2 simple tasks, with the onset of the 2nd task relative to the 1st task carefully controlled. The possibility of an age-related reduction in the ability to generate and execute 2 similar motor programs was explored by requiring either a manual response to both tasks or a manual response to the 1st and an oral response to the 2nd and was confirmed by the evidence. The age-related interference was greater than would be expected from a general slowing of processing in older adults. The possibility of an age-related reduction in the capacity to process 2 tasks in the same perceptual input modality was explored by presenting both tasks in the visual modality or the 1st task in the auditory modality and the 2nd task in the visual modality and was not supported by the evidence. There was greater interference when both tasks were in the same modality, but it was equivalent for older and younger adults. Age differences in dual-task interference appear quite localized to response-generation processes.

Adolescent↗

PubMed2000

Locating and fractionating working memory using functional neuroimaging: storage, maintenance, and executive functions.

Working memory encompasses the short-term store of information and operations on that information. We review functional neuroimaging studies that have attempted to determine cortical areas involved in working memory functions. Current research suggests distinct systems for verbal information, visual objects, and spatial locations. Passive storage buffers appear to be located in posterior brain areas, whereas active maintenance of the information involves ventrolateral prefrontal areas. More complex, executive operations appear to recruit dorsolateral prefrontal cortex and anterior cingulate cortex. The possible involvement of reciprocal circuits including frontal cortex, basal ganglia, and thalamus is also discussed.

Brain↗

PubMed2000

Further evidence that negative priming in the Stroop color-word task is equivalent in older and younger adults.

In 2 experiments, possible adult age differences in negative priming were explored using several variants of the Stroop color-word task. Negative priming was at least as high in the older adults as in the younger adults in every variant. Negative priming varied as a function of condition, but the age equivalence was unaffected. This result was true even when the possibility of general slowing was taken into account. Across conditions, interference and negative priming were positively correlated. The results do not permit a clear choice between the 2 major theoretical explanations of negative priming, inhibition and memory retrieval; they do show that negative priming can be systematically manipulated within an experimental paradigm.

Adolescent↗

PubMed1999

Age-related differences and similarities in dual-task interference.

Differences between younger adults (mean age, 20.7 years) and older adults (mean age, 72.7 years) in dual-task performance were examined in 7 experiments in which the overlap between 2 simple tasks was systematically varied. The results were better fit by a task-switching model in which age was assumed to produce generalized slowing than by a shared-capacity model in which age was assumed to reduce processing resources. The functional architecture of task processing appears the same in younger and older adults. There was no evidence for a specific impairment in the ability of older adults to manage simultaneous tasks. There was evidence for both input and output interference, which may be greater in older adults.

Adult↗

PubMed1997

Age-related equivalence of identity suppression in the Stroop color-word task.

Previous failures to find reliable identity suppression (identity negative priming) in older adults have led to conclusions that older adults suffer from an impairment in the inhibitory component of selective attention. Here, 2 experiments using the Stroop procedure found identity suppression in older adults that was both reliable and equivalent to that in younger adults. Experiment 1 with repeated target colors produced correlations consistent with an episodic retrieval explanation of identity suppression, Experiment 2 without repeated targets produced correlations inconsistent with the episodic retrieval interpretation. These patterns were found for both younger and older adults. No evidence was found for reduced identity suppression that would be consistent with a general inhibitory impairment in older adults.

Adult↗

PubMed1995

Adult age differences in the inhibition of return of visual attention.

Responses to targets are slower when they appear at a location to which attention has previously been directed than when they appear at other locations. This inhibition of return (IOR) effect is subserved by posterior brain attentional systems. In 4 experiments the IOR effect in elderly adults was found to be at least as large as in young adults for both discrimination tasks and for detection tasks. The time course and the spread of inhibition within the visual field were also equivalent in the 2 age groups. Additive factors logic was then used to test the hypothesis that the Stroop and IOR effects are due to a common mechanism, a failure to suppress attention. This hypothesis was not confirmed. The results of the 6 experiments are consistent with the hypothesis that there are changes in posterior brain systems responsible for selective attention to a location, contrary to prior claims. They cannot be explained by a general slowing of processing in old age.

Adult↗

PubMed1993

Evidence for the selective preservation of spatial selective attention in old age.

Younger and older adults were tested in 2 versions of the Stroop color-word task: a color-block version in which the color word was adjacent to a color block and a color-word version in which the word was printed in color. An advance cue preceded the stimulus by 100 to 300 ms, indicating where it would appear. Age differences were small on the color-block version and large on the color-word version. These results are consistent with the speculation that posterior brain attention systems responsible for selecting a spatial location are relatively well preserved with advancing age but that anterior brain attention systems responsible for selecting a line of processing are compromised.

Adolescent↗

PubMed1992

Allocation of visual attention in younger and older adults.

Younger and older adults were compared in three experiments, using procedures that had been shown to affect the spread of visual attention. The attentional effects found in previous experiments were replicated. A broader focus of attention speeded responses to peripheral targets. In addition, two established findings concerning aging were replicated: Responses were slower in older than in younger adults, and, in certain conditions, they slowed more rapidly as target eccentricity increased. No interactions of age effects with attentional manipulations were found. The results of all three experiments were consistent with the interpretation that younger and older adults do not differ in the allocation of attention.

Adult↗

PubMed1991

Attentional and perceptual contributions to the identification of extrafoveal stimuli: adult age comparisons.

Gerontological researchers have been cautioned that conclusions about age differences in attention may have been inferred from data that, in fact, reflected age differences in perceptual processing of stimuli falling outside the fovea (Cerella, 1985). Presumably, the experimental manipulations on which Cerella based his caution induced a broad focus of attention so that changes in perceptual processing would not be confounded with changes in attention. Experiment 1 tested this by comparing a condition similar to Cerella's with another in which attention was narrowly focused at fixation. The results replicated Cerella's findings. In addition, there were greater age differences when attention had been narrowly focused, showing that attentional effects can be separated from the effects reported by Cerella. Experiment 2 showed that age differences in extrafoveal perception could be removed by increasing the duration of the target from 200 to 2000 ms, suggesting that the perceptual deficits in older adults are due to differentially lengthened processing of stimuli outside the fovea.

Adolescent↗

PubMed1990

Age differences and similarities in the effects of cues and prompts.

A series of 6 experiments investigated the use of cues and prompts by younger and older adults. Cues provide useful information about an impending target, even though the information is not always valid. Prompts provide an instruction about what aspect of the target is to be responded to. The costs and benefits of cues were most consistent with models in which the attentional resources that are shifted in response to the cue were as large or larger in older adults as they were in younger adults. The results with both cues and prompts converged on the conclusion that the time course of processing and using a cue or prompt is the same in younger and older adults. The attentional resources tapped by these procedures cannot be the diminished processing resource to which many age differences in cognitive performance are attributed.

Adolescent↗

PubMed1990

Structural equation models of relationships between exercise and cognitive abilities.

Data were obtained from 300 men and women aged 55 to 91. Separate structural equation models of relationships between physical exercise and 3 cognitive performance variables--reaction time, working memory, and reasoning--fit the data well. Other variables in the models were age, health, education, and morale. Age and exercise affected each performance variable directly; education had a direct effect on reasoning only. There were also indirect effects of age and health on performance variables, mediated through exercise. The main hypothesis of the study, that exercise contributes to performance, was supported. A large decrease in model fit resulted when the path from exercise to each performance variable was deleted. Hypotheses that age-related deficits are primarily accounted for by lack of exercise or by poor health were not supported.

Aged↗

PubMed1990

The game of bridge as an exercise in working memory and reasoning.

Fifty bridge players and 50 nonplayers, between the ages of 55 and 91, were given tests of working memory, reasoning, reaction time, and vocabulary. Data were analyzed using multivariate and univariate analyses of variance with age as a covariate. Results indicated that the players outperformed nonplayers in measures of working memory and reasoning, but not vocabulary and reaction time. Results were consistent with the hypothesis that bridge, which provides specific experience in working memory and reasoning, should enhance performance in tasks tapping these abilities and not enhance performance in unrelated abilities. Because the data were correlational, the rival hypothesis that bridge playing selects for individuals who perform better at working memory and reasoning tasks could not be rejected.

Aged↗

PubMed1989

Relationships between physical exercise and cognitive abilities in older adults.

We investigated relationships between physical exercise and the cognitive abilities of older adults. We hypothesized that the performance of vigorous exercisers would be superior to that of sedentary individuals on measures of reasoning, working memory, and reaction time. We gave a series of cognitive tasks to 62 older men and women who exercised vigorously and 62 sedentary men and women. Multivariate and univariate analyses of variance, with age and education as covariates, indicated that the performance of the exercisers was significantly better on measures of reasoning, working memory, and reaction time. Between-group differences persisted when vocabulary, on which the performance of exercisers was superior, was used as a third covariate. Subsequent analyses showed that neither self-rated health, medical conditions, nor medications contributed to the differences between exercise groups. Results suggest that the possible contribution of physical exercise to individual differences in cognition among older adults should be further investigated.

Adult↗

PubMed1987

Age differences in the speed of cognitive operations: resolution of inconsistent findings.

Gaylord and Marsh (1975) and Cerella et al. (1981) found that the speed of cognitive operations in the mental rotation paradigm was significantly slower for groups of older adults with mean ages of 68 and 73 years than for groups of younger adults. Jacewicz and Hartley (1979) found no difference between a group of adults with a mean age of 56 and a group of younger adults. The present study included a group of younger adults, a late-middle age group with a mean age of 56, as well as an older group with a mean age of 74. The results replicated both those reported by Jacewicz and Hartley (1979) and those reported by Gaylord and Marsh (1975) and Cerella et al. (1981). They are consistent with a hypothesis of generalized central nervous system slowing, but they show that the slowing does not begin to affect performance until the sixth decade of life.

Adult↗

PubMed1986

Age differences and changes in sprint swimming performances of masters athletes.

Sprint swimming speeds were compared in cohorts of masters swimmers ranging from 25-29 to 65-69 years of age in 1976. The cross-sectional comparisons were repeated for the same cohorts in 1981. The ten fastest performers in the United States in each cohort were obtained for women (n = 1407) and men (n = 1437) in 50-yd and 100-yd races for each of the four competitive strokes. Results showed the greatest decrement in performance with increasing age for the butterfly stroke. The slowing with age was unaffected by the length of the race. The results supported the hypothesis that age differences in performance are due primarily to differences in muscle strength. As in previous studies, changes in performance with age in the same cohort were substantially smaller than differences between cohorts.

Adult↗

PubMed1986

Instruction, induction, generation, and evaluation of strategies for solving search problems.

Two experiments found that older adults can execute efficient strategies for search problems when instructed in their use. They continue to use these strategies after instruction and transfer their use to similar problems. The results did not support the contention that older adults can be led to discover efficient strategies by manipulation of salient stimulus features such as color. It seemed likely that age differences in search performance were due to deficiencies in strategy production. A third experiment directly examined the generation and evaluation of strategies by younger and older adults. Age differences were localized in optimal strategies; older adults were less likely to generate or use optimal strategies and rated them as less informative than did younger adults.

Adult↗

PubMed1984

Performance changes in champion swimmers aged 30 to 84 years.

Performance changes in champion swimmers aged 30 to 84 years were examined using both longitudinal and repeated cross sectional designs. When single cross sectional slices of the data were analyzed, decrements in performance with advancing age were found, similar to those reported in older track athletes. When the same individuals or cohorts were followed over time, the changes were found to be substantially smaller. The results also showed greater age changes in short, anaerobically-swum races than in longer, aerobically-swum races.

Adult↗