Raymond E. Sanders

Age differences in overlapping-task performance: Evidence for efficient parallel processing in older adults.

Two psychological refractory period (PRP) experiments were conducted to examine overlapping processing in younger and older adults. A shape discrimination task (triangle or rectangle) for Task 1 (T1) and a lexical-decision task (word or nonword) for Task 2 (T2) were used. PRP effects, response time for T2 increasing as stimulus onset synchrony (SOA) decreased, were obtained for both age groups. The effect of word frequency on T2 was smaller at the short SOA than at the long SOA, reflecting slack effects, which were larger for older than younger adults in both experiments. These results suggest that older adults can perform lexical access of T2 in parallel with the processing of T1 at least as efficiently as younger adults.

Metamemory in older adults: the role of monitoring in serial recall.

Older and younger adults were asked to think aloud while studying sets of pictures matched in difficulty for immediate serial recall. When instructed only to remember, young adults tended to study longer, rehearse more, and recall better than did older adults on the most difficult lists. Young adults were also much more likely to spontaneously test themselves during study in the most difficult condition. Older adult groups instructed either to study longer or to self-test, both showed improved recall. Only the older adults who had been instructed to self-monitor, however, recalled better on tests of short-term maintenance and generalization; overt rehearsal data showed that these older adults continued to test themselves. Metamemory deficits may be present with older adults when a strategy, like self-testing, is needed to generate metamemorial knowledge. Strategies such as self-testing can be easily taught, however, and they hold promise of being useful across situations.

How Shared Are Age-Related Influences on Cognitive and Noncognitive Variables?

Several theories have suggested that age-related declines in cognitive processing are due to a pervasive unitary mechanism, such as a decline in processing speed. Structural equation model tests have shown some support for such common factor explanations. These results, however, may not be as conclusive as previously claimed. A further analysis of 4 cross-sectional data sets described in Salthouse, Hambrick, and McGuthry (1998) and Salthouse and Czaja (2000) found that although the best fitting model included a common factor in 3 of the data sets, additional direct age paths were significant, indicating the presence of specific age effects. For the remaining data set, a factor-specific model fit at least as well as the best fitting common factor model. Three simulated data sets with known structure were then tested with a sequence of structural equation models. Common factor models could not always be falsified--even when they were false. In contrast, factor-specific models were more easily falsified when the true model included a unitary common factor. These results suggest that it is premature to conclude that all age-related cognitive declines are due to a single mechanism. Common factor models may be particularly difficult to falsify with current analytic procedures.

Modification of Concept Identification Performance in Older Adults

A sequential training procedure combining operant and cumulative learning hierarchy principles was found effective in reducing the decrement in concept identification performance typically observed in older adults. Subjects aged 63 to 83 years were given a pretest and posttest, each involving a three-category unidimensional concept identification problem. The training and reinforced training subjects were given three training sessions between pretest and posttest. Training involved a programmed learning sequence designed to facilitate the development of an effective solution strategy. Control subjects were given only the pretest and posttest, while practice subjects were given three additional practice sessions. Substantial improvement was found in both the training and reinforced training groups, but only slight improvement obtained in the practice and control groups. These results were considered consistent with recent conceptions of cognitive and intellectual development in the older adult in which performance deficits are largely attributed to experiential factors.

Influence of Probable Alzheimer's Disease on Multiplication Verification and Production Abstract

Abstract We compared the multiplication verification and production performances of healthy younger (n = 20) and older (n = 20) adults to that of mildly demented (Mini Mental Status Exam range: 19–27) individuals diagnosed with probable Alzheimers disease (n = 18). While healthy older adults and Alzheimers patients were slower than younger adults, the older adults actually showed significantly smaller problem-size effects for verification and production reaction time (RT) tasks. These results suggest that retrieval of multiplication fact knowledge from long-term memory for multiplicands greater than zero remains largely intact in mildly demented individuals diagnosed with probable Alzheimers discase, although these individuals may have more difficulty with volitional retrieval because group differences were larger for some production analyses (require volitional retrieval) than for verification analyses (simply requires familiarity). However, for problems involving zero multiplicands (but not 1’s), healthy older adults and especially Alzheimers patients showed significantly higher error rates than younger adults, suggesting that rule retrieval of correct solutions in memory was impaired in both of these older groups for problems involving zero operands. Also, when RT was regressed on problem size across groups, there was no effect for problem size for the production task for Alzheimers patients—but there was for healthy younger and older adults. Finally, when verifying problems, there was a significant problem size effect of comparable magnitude for all three groups.

Adult age comparisons in the processing of event frequency information.

The usual superiority in frequency-of-occurrence judgments of younger vs. older subjects was hypothesized to result from greater strategic encoding of the materials conveying frequency information. A subject-paced, visual search task was designed to control nontarget word encoding. Relative frequency judgments for the nontarget word pairs were equally accurate for younger and older subjects, and performance of both groups was above chance. Results suggest that strategic cover-task encoding can induce age differences in incidental frequency processing. Consistent with a nonoptimal as opposed to an optimal view, automatic processes require only minimal capacity for above-chance performance, but additional strategic resources can increase performance. When such additional resources are used more by younger than by older subjects, the former are better in frequency performance.

Sensitivity to sucrose in smokers and nonsmokers: A comparison of TSD and percent correct measures

Ten smokers and 10 nonsmokers were compared for taste sensitivity to sucrose on two discrimination tasks, one at near-threshold (NT) concentration level and one at suprathreshold (ST) concentration level. The data were analyzed using the ds and area under ROC curve measures based on the theory of signal detection (TSD). and by using the percentage correct responses. Analysis of both TSD measures showed smokers to be significantly more sensitive than nonsmokers on the NT .task and more sensitive on the ST task, but not significantly so. Comparison of mean percent correct responses showed no significant differences. A reflexive enhancement phenomenon was suggested as a possible interpretation. A decreased sensitivity to the bitter taste in smokers apparently results in an increased sensitivity to the sweet taste.

Misguided multiplication: Creating false memories with numbers rather than words

We built Deese (1959)/Roediger and McDermott (1995) (DRM) false memory lists composed of multiplication problems rather than words. Half these lists contained table-related, near neighbors (e.g., 3 × 7 = ??, 3 × 9 = ??) of a missing multiplication answer lure (e.g., 24). The other half contained problems unrelated to the lure (e.g., 5 × 5 = ??, 11 × 3 = ??). Participants solved each problem in a single list and then took immediate recognition (Experiment 1) or recall and then recognition tests (Experiment 2) for the answers. Many people misremembered that the lure was an answer to a study-phase problem, but only when solving the study list that contained the lure’s neighbors. False memory was also greater for some list-lure combinations than others, as seen previously with words. We have thus demonstrated that numbers can also produce false memory, and we use the mental math and DRM task literatures to explain these results.

Aging and negative priming: is ignored information inhibited or remembered?

We had younger and older adults complete two tasks that tested the attentional- and memory-based inhibition models of negative priming. One task violated May, Kane, & Hasher (1995, Psychological Bulletin, 118, 35-54) criteria for measuring just attentional inhibition, by including a repeated-target condition. The other task complied with these criteria and included a depth of processing manipulation, where participants selected prime targets based either on their letter-length (nonsemantic processing) or weight (semantic processing). On balance, results supported the memory model, because depth of processing clearly moderated younger adult negative priming, and older adults displayed negative priming only in the task satisfying the attentional-inhibition criteria (i.e., the depth of processing task). We conclude that memory factors moderate negative priming, and that May et al.s criteria fail to predict when older adults will show the effect.We had younger and older adults complete two tasks that tested the attentional- and memory-based inhibition models of negative priming. One task violated May, Kane, & Hasher (1995, Psychological Bulletin, 118, 35-54) criteria for measuring just attentional inhibition, by including a repeated-target condition. The other task complied with these criteria and included a depth of processing manipulation, where participants selected prime targets based either on their letter-length (nonsemantic processing) or weight (semantic processing). On balance, results supported the memory model, because depth of processing clearly moderated younger adult negative priming, and older adults displayed negative priming only in the task satisfying the attentional-inhibition criteria (i.e., the depth of processing task). We conclude that memory factors moderate negative priming, and that May et al.s criteria fail to predict when older adults will show the effect.

A beautiful day in the neighborhood: What factors determine the generation effect for simple multiplication problems?

In four experiments, we examined the generation effect for the free recall of simple multiplication answers. Large-product-size problems showed a consistent generation-effect advantage over smallproduct-size problems, except when each answer was generated twice, via two different sets of operands (Experiment 2). Also, measures of problem-solution time and strategy use accounted for the largeproduct-size advantage. Across experiments, however, small-product-size problems (but not largeproduct-size problems) showed considerable variation in the size of their generation effect. We discovered that solving small-product-size problems via direct memory retrieval increased the episodic recall probability of other problems that were near neighbors to the generated answer, and we attribute this result to a spreading activation mechanism in semantic memory. A measure of neighbor activations, combined with RT to solve each problem, accounted for 51% of the observed generation-effect variance.