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Biomedical subjects

T A Salthouse

Publications and source records attributed to T A Salthouse.

At least 19 recordsLinked to original sources
PubMed1992

Influence of processing speed on adult age differences in working memory.

Two studies are reported in which adults ranging from 18 to 80 years of age performed tasks designed to measure working memory functioning and perceptual comparison speed. The results from both studies indicated that statistical control of the measures of perceptual comparison speed greatly attenuated the age-related variance in measures of working memory even when working memory was assessed under self-paced conditions. Additional results in the second study supported the hypothesis that the speed influence was manifested in the rate of activating information rather than in the rate at which it was lost as a function of time or other processing.

Adolescent↗
PubMed1992

Within-context assessment of age differences in working memory.

Five experiments were conducted to investigate the mechanisms by which age-related reductions in working memory capacity might mediate age-related declines in cognitive functioning. A prototypical cognitive task, cube comparison, was implemented on a computer to allow measures of the availability of different types of information while subjects were attempting to solve the task. Young and old adults were equivalent in a measure postulated to reflect the temporary preservation of untransformed stimulus information. However, older adults, relative to young adults, exhibited greater reductions in accuracy as the processing requirements increased, and they made significantly more redundant or repetitive requests for information. These results are consistent with the view that increased age may be associated with a decreased ability to transform or abstract information while also preserving the products of earlier processing.

Adult↗
PubMed1992

What do adult age differences in the Digit Symbol Substitution Test reflect?

Results from three studies are reported in which adults between 18 and 84 years of age performed various versions of the Digit Symbol Substitution Test. The first study revealed that the age-related declines in digit-symbol performance were largely independent of both the amount of education the participants had received and their self-reported health status, and were characterized by a gradual shift in the entire distribution of scores with little age-related increase in variance. The age relations were greatly attenuated after statistical control of a composite measure of perceptual comparison speed, however, implying considerable commonalities between perceptual comparison speed and what the Digit Symbol Substitution Test measures. Two further studies indicated that young and old adults appeared to use similar strategies to perform the task, and were nearly equivalent in the proportions of time devoted to writing the responses and searching the code table.

Adult↗
PubMed1992

Working-memory mediation of adult age differences in integrative reasoning.

Three research methods were used to investigate the hypothesized mediational influence of working memory on age-related differences in integrative reasoning. Results from all three procedures were consistent with the hypothesis because (1) statistical control of an index of working memory attenuated the age differences in reasoning accuracy, (2) young adults were more accurate than older adults in a measure reflecting the preservation of information during processing, and (3) young adults performing the task with a concurrent memory load exhibited a qualitative pattern of performance similar to that of older adults performing the task without a concurrent memory load.

Adult↗
PubMed1991

Effects of adult age on structural and operational capacities in working memory.

Eight experiments were conducted in which young adults and older adults were asked to report the latest value of 1 of several continuously changing numeric or spatial variables. Accuracy of reporting the current value of the target variable was lower with increases in the number of potentially relevant variables and with increases in the number of required processing operations. Young and older adults exhibited similar effects of the number of potentially relevant variables (hypothesized to be sensitive to the structural capacity of working memory) and of the number of required processing operations (hypothesized to be sensitive to the operational capacity of working memory), but older adults were generally less accurate than young adults.

Adult↗
PubMed1991

Age and experience effects on the interpretation of orthographic drawings of three-dimensional objects.

Adults of different ages and experience levels attempted to recognize wire-frame drawings of 3-dimensional objects originally displayed in orthographic views. Although only slight age relations were evident on a measure of decision accuracy in the criterion task, increased age was associated with poorer performance on several tasks hypothesized to assess component processes. Furthermore, there was no significant alteration in any of the performance measures by statistically controlling for amount of relevant experience, and there was no evidence that people of different ages, or different levels of experience, relied on different abilities to perform the criterion task. These results seem to imply that experience neither mediates nor moderates age-related influences on certain measures of relatively basic cognitive processes.

Adult↗
PubMed1990

Memory factors in age-related differences in simple reasoning.

Adults in their 50s were compared with adults in their late teens or 20s in the accuracy of relatively simple reasoning decisions involving varying amounts of information. Because the magnitude of the age differences in decision accuracy was independent of the amount of information relevant to the decision, it was suggested that adults in their 20s and 50s do not differ in the effectiveness of integrating information across multiple premises. However, the 2 groups differed in the accuracy of trials involving only a single relevant premise, and thus it was inferred that 1 factor contributing to reasoning differences within the age range from 20 to 60 may be a failure to encode, or retain, relevant information.

Adult↗
PubMed1990

Effects of increased processing demands on age differences in working memory.

Three studies investigated (a) the plausibility of the claim that increasing the processing demands in a memory task contributes to greater involvement of a central processor and (b) the effects of altering reliance on the central processor on the magnitude of age-related differences in working-memory tasks. In the first study, young adults performed versions of 2 tasks presumed to vary in the degree of reliance on the central processor. In the second and third studies, young and older adults performed versions of a computation-span task that were assumed to vary along a rough continuum of the amount of required processing. The results indicated that although a central processor appears to be involved when working-memory tasks require simultaneous storage and processing of information, age-related differences in working memory seem to be determined at least as much by differences in the capacity of storage as by differences in the efficiency of processing.

Adult↗
PubMed1990

Age, self-assessed health status, and cognition.

Data from a recent project involving 362 adults ranging from 20 to 79 years of age were reanalyzed to examine the effects of statistical control of self-assessed health status on the age trends in several measures of cognitive functioning. The major result was that the age trends were virtually identical with, and without, control of the health-status variable. Implications of the views that the lack of health influences was due to a narrow range of health status or to insensitive assessment of health status were discussed.

Adult↗
PubMed1990

Influence of experience on age differences in cognitive functioning.

To the extent that adult age differences in measures of cognitive performance have implications for functioning outside the psychological laboratory, the question of the role of experience as a potential moderator of these differences becomes extremely important. Three categories of research relevant to this issue are reviewed, and methodological limitations of each type of research are discussed. Although it is frequently asserted that experience minimizes cognitive differences associated with aging, the evidence currently available does not appear consistent with a strong experiential moderation of age-related effects in cognitive performance. However, the paucity of relevant studies and the methodological weaknesses of those that do exist preclude a definitive conclusion at the present time. Additional research with improved methodology is necessary before strong conclusions can be reached concerning effects of experience on age differences in cognition.

Activities of Daily Living↗
PubMed1989

Effects of adult age and working memory on reasoning and spatial abilities.

Three predictions were derived from the hypothesis that adult age differences in certain measures of cognitive functioning are attributable to age-related reductions in a processing resource such as working-memory capacity. Each prediction received at least some degree of empirical support in a study involving 120 males ranging between 20 and 79 years of age. First, older adults exhibited greater impairments of performance than did young adults when task complexity increased and more demands were placed on the limited processing resources; second, the magnitudes of these complexity effects were highly correlated across verbal (reasoning) and spatial (paper folding) tasks. Finally, statistical control of an index of a working-memory processing resource attenuated the effects of age on the measures of cognitive performance. It was concluded that further progress in understanding the mechanisms of the relation between age and cognitive functioning will require improved conceptualizations of the nature of working memory or other hypothesized mediating constructs.

Adult↗
PubMed1989

Structural and operational capacities in integrative spatial ability.

Four experiments were conducted to explore a distinction between structural capacity, the maximum number of informational units that can be temporarily stored, and operational capacity, the number of processing operations that can be executed while simultaneously preserving the products of earlier processing. The results, from a synthesis task requiring the integration of successively presented line segments into a composite stimulus, revealed that there were little or no age differences in structural capacity but large age differences favoring young adults in operational capacity. An attempt was also made to determine how much earlier information was available after each additional processing operation, but equivocal results precluded a definitive conclusion about the exact nature of the age differences in operational capacity.

Adult↗
PubMed1989

Memory and age differences in spatial manipulation ability.

Young and old adults were asked, in 3 experiments, to make decisions about the identity of line segment patterns after either adding or subtracting line segments from the original pattern. On some of the trials, the line segments from the initial display were presented again in the second display to minimize the necessity of remembering early information during the processing of later information. Although this manipulation presumably reduced the importance of memory in the tasks, it had little effect on the magnitude of the age differences in any of the experiments. Because the 2 groups were equivalent in accuracy of simple recognition judgments, but older adults were less accurate when the same types of decisions were required in the context of an ongoing task, the results suggested that older adults may be impaired in the ability to retain information while simultaneously processing the same or other information.

Adolescent↗
PubMed1988

Investigation of student status, background variables, and feasibility of standard tasks in cognitive aging research.

Data are reported on a variety of cognitive tasks from 62 college students and 362 nonstudent adults between 20 and 79 years of age. The goals of the project were as follows: (a) to investigate the validity of the practices of using college students and adults over age 65 in studies of cognitive aging, (b) to examine the influence of a variety of background variables on age trends in cognitive performance, and (c) to initiate the development of standard tasks to assist in the description of subject samples in cognitive aging research. The age trends in cognitive performance were relatively independent of an assortment of background variables, but because college students were atypical of their age group in several performance measures they may be suspect as the young-adult control subjects in investigations involving these types of measures. Adults over the age of about 65 appear to exhibit accelerated slowing of speeded performance, but in other respects perform about as one would expect on the basis of the age trends observed between the ages of 20 and 65.

Adult↗
PubMed1988

Initiating the formalization of theories of cognitive aging.

Although the relevant knowledge base is still impoverished, the time may be appropriate to attempt to develop and investigate formal models of cognitive aging that incorporate explicit mechanisms to account for age differences frequently observed in measures of cognitive functioning. An initial model based on an associative network metaphor is described, in which age declines in fluid or process aspects of cognition are attributed to a reduction in either the number of simultaneously active nodes, the maximum allowable activation, or the rate of propagating activation between nodes. Results from a computer simulation are consistent at a first level of approximation with many cognitive aging phenomena, and the model is shown to provide a plausible account of age differences in an area that has previously resisted explanation. Although this particular model is only one of many that could be formulated at the present time, it is argued that more rapid progress in theoretical understanding of cognitive aging phenomena will be achieved by attempting to specify one's assumptions and hypotheses in a formal and explicit manner.

Aged↗
PubMed1988

Utilization of path-analytic procedures to investigate the role of processing resources in cognitive aging.

Data from two batteries of tests administered to 129 and 233 adults, ranging from 20 to 79 years of age, were analyzed to explore the viability of models postulating that age differences in the quantity or efficiency of processing resources are responsible for many of the age differences observed in cognitive functioning. Path-analysis procedures were used to estimate the direct and indirect, or resource-mediated, effects of age on cognitive performance. Results, with simple speed and memory measures serving as the indexes of processing resources, indicated that there was little support for a strong resource model, and evidence derived from a weak resource model suggested that resource-mediated contributions to age differences are small, relative to those not mediated by processing resources.

Adult↗
PubMed1988

Temporal memory over the adult lifespan.

Performances of noncollege student young adults, middle-aged adults, and elderly adults were contrasted on word temporal memory and paired-associate learning tasks. A comparison group of college-student subjects was also evaluated on each task. Significant effects for age variation were found for each task. The age sensitivity for temporal memory conflicts with one of the criteria commonly established for determining the automaticity of a memory task. In addition, moderately high positive correlations were found for each age group between word temporal memory scores and paired-associate learning scores, implying the involvement of effortful processes over the adult lifespan in word temporal memory.

Adult↗