Biomedical subjects

A D Fisk

Publications and source records attributed to A D Fisk.

At least 37 records · Page 2Linked to original sources

PubMed1994

Brinley plots and theories of aging: the explicit, muddled, and implicit debates.

We evaluated the debates concerning Brinley plots and the associated theories of age-related slowing. We concluded that an explicit debate regarding a single-factor, general slowing model was no longer a debate as most, if not all, agree to the disconfirmation of that model. We address sources of confusion in the debates that have muddled the areas of genuine disagreement. When the confusion is lifted, the remaining debate centers, rightly, on evaluation of theories of aging. We show that Brinley plot analyses can lead to both falsely accepting and falsely rejecting theories of age-related slowing. Although plotting data most certainly can assist with the evaluation of cognitive theory, we argue that models of performance and learning must play a more central role in advancing theories of cognitive aging.

Adolescent↗

PubMed1993

Disruption and maintenance of skilled visual search as a function of degree of consistency.

The present experiment was conducted to investigate the effects of varying degrees of task consistency on the performance and maintenance of skill in a semantic-category visual search task. Four groups of participants first received 6000 trials of consistent mapping (CM) training on two different categories. The participants then performed 4000 trials in which one of the previously trained categories remained 100% consistent, whereas the other previously trained category became either 100%, 67%, 50%, or 33% consistent. This second phase of the experiment allowed for the examination of disruption of the search skill as a function of degree of consistency. Subsequent to the degree of consistency manipulation, 100% consistency was restored and participants performed another 4200 CM trials. Results indicate that performance was disrupted by inconsistency and that disruption increased as consistency decreased. On the return of task consistency, performance improved rapidly to predisruption levels, though some performance disruption was evident. Theoretical and practical implications are discussed.

Adolescent↗

PubMed1992

General slowing alone cannot explain age-related search effects: reply to Cerella (1991)

Cerella (1991) has argued that the performance of older adults in the Fisk and Rogers (1991) study is a linear function of the performance of younger adults that is independent of task-specific cognitive requirements. We demonstrate that this is not the case. First, we show that the scatter plot analyses used by Cerella can hide the very task-specific age-related slowing they were designed to reveal. Second, we demonstrate that the percentage of variance explained by such analyses can be misleading. Third, we show that there are reliable differences across tasks in the parameters relating younger and older adults' performance. Finally, we argue that the general, task-independent proportionate slowing that Cerella suggested explains so much of the variance in age-related performance is actually an average slowing that is a function of a relatively small task-independent and a relatively large task-dependent factor.

Adult↗

PubMed1992

Retention of trained performance in consistent mapping search after extended delay.

We examined the retention of performance in memory, visual, and hybrid memory/visual search after subjects received extensive consistent mapping (CM) practice. In the first two experiments we examined retention of detection performance in memory scanning (Experiment 1) and in visual search (Experiment 2) approximately one month after training. In the third experiment we examined performance 1, 30, 90, 180, and 365 days following training on pure visual and hybrid memory/visual semantic-category search tasks. We examined retention at intervals up to one year after practice as a function of amount of CM practice. In addition, we assessed the degree of category activation (performance on untrained words from the trained categories) at each retention interval. Across experiments, we found no decay in CM trained memory search and minimal decay in pure visual search. Significant decline in CM performance was largely attributable to performance in the hybrid memory/visual search conditions. These data reconcile previously equivocal retention results for CM trained search performance.

Adult↗

PubMed1991

Are age differences in consistent-mapping visual search due to feature learning or attention training?

In this experiment, the ability of young and old adults to differentially modify the attention-attraction strength of targets and distractors relative to feature differentiation was examined. Eight young and 8 old subjects were trained for 8,000 trials in conditions that allowed maximal target-distractor strength differentiation, inhibited target-distractor strength differentiation but facilitated feature differentiation, or inhibited both target-distractor strength differentiation and feature differentiation. Age-related performance was assessed between and within conditions during training and with reversal conditions where the roles of targets and distractors were switched. The pattern of data during training and at reversal supports the proposal that age differences in extended-practice visual search are due to differences in the ability to differentially strengthen targets and distractors.

Adult↗

PubMed1991

Toward an understanding of age-related memory and visual search effects.

Young and old Ss were tested in 3 experiments conducted to explore factors leading to age-related performance differences in consistent mapping (CM) and varied mapping (VM) search tasks. The separate and combined influences of memory scanning and visual search on age-related search effects were examined. In both CM letter and CM semantic category search, age interacted with comparison load in visual and hybrid memory-visual search conditions, whereas differential age effects were not present in pure memory search. For VM search, age effects were present only in pure memory search. These data support the view that the separation of type of search training (CM and VM) as well as memory and visual search components is critical for predicting age-related performance differences. The dissociation of the pattern of age effects in memory and visual search suggests that memory and visual search involve different processing mechanisms.

Adult↗

PubMed1991

Age-related differences in the maintenance and modification of automatic processes: arithmetic Stroop interference.

This experiment was designed to investigate whether well-learned "automatic" processes remain stable as a function of age, as well as to determine whether the ability to modify these automatic processes is disrupted for older adults. We used an arithmetic Stroop task to measure the stability of an automatic process. Nineteen young (mean age 22) and 19 old (mean age 75) adults participated in three experimental sessions, each of which consisted of 15 blocks of 30 trials. Although the young subjects had faster verification times overall than did the old adults, both young and old subjects showed significant interference effects. For the young adults, there was a decrease in the interference effect with practice, which suggested that they were learning to inhibit the automatic process of performing the arithmetical operation. However, the old adults showed no significant decrease in the associative interference effects. This implies that the older adults were impaired in their ability to inhibit automatic processes, even when those processes interfered with performance. Theoretical and practical training implications are discussed.

Adult↗

PubMed1991

Recombination of automatic processing components: the effects of transfer, reversal, and conflict situations.

This research was conducted to evaluate the effects of compatible and incompatible automatic processes on performance. Subjects were trained for 8400 trials of consistent mapping practice in a semantic category visual search task and then transferred for 2352 trials to conditions that utilized the trained component processes in various ways. Results indicate that if the components were reused in a compatible fashion (target and distractor transfer), there was positive transfer. Target and distractor reversal resulted in equivalent and severe performance disruption that persisted for the entire retraining period. Target conflict produced disruption equivalent to the reversal conditions. Distractor conflict resulted in less initial disruption, which dissipated before the end of the retraining period. The results are discussed in terms of agreement with strength-theoretic views of visual search and in terms of practical training and retraining issues.

Adult↗

PubMed1991

A cognitive engineering approach to improving signalized left turn intersections.

This research evaluated the effect of providing advanced left turn information to individuals faced with deciding whether or not it is safe to turn at a signalized intersection. Younger (mean age 37 years) and older (mean age 71 years) drivers were tested in simulations of approaching an intersection with and without advanced cueing. Experiment 1 used a featureless background; Experiment 2 used an animated presentation of traffic control displays. In both experiments the subjects had to determine whether or not they had right-of-way to make a left turn. Exaggerated error rates and increased decision latencies for displays conveying unprotected turn status occurred in both studies. Cueing drivers with advanced notice of the decision rule through a redundant upstream posting of sign elements improved both accuracy and latency of younger and older drivers' decisions.

Adult↗

PubMed1990

Understanding strategic usage of 'on-the-job' reference aids.

The present set of studies examined how reference aids are collectively used to resolve problems. In addition, the present research investigated the strategies employed by documentation users as they resolved work-related questions. Subjects were given a series of questions and asked to locate the answers in a number of different types of documentation. Results of the first experiment indicated that the users' success was largely determined by their adopting an appropriate search heuristic. In the second study, the users were provided with a heuristic during training and their performance was compared with that of an expert user of the documentation. Findings from the second study revealed no difference in accuracy between the subjects and the expert; however, important qualitative strategy differences did exist between the subjects and the expert. The implications of the present results to the design of on-line computerised documentation are discussed.

Journal Article↗

PubMed1990

Consistent and varied memory/visual search: is there an interaction between age and response-set effects?

Interactions of stimulus consistency and response-set were examined after extensive consistent (CM) and varied mapping (VM) practice for young (mean age 20) and old (mean age 74) adults. The experiment examined whether reduced response complexity would lead to equivalent consistent mapping search performance across age groups. Subjects received 2,240 training trials each for CM and VM versions of a hybrid memory/visual search task. During training two response conditions were used: (1) respond only when a target was present (Yes-only responding) and (2) respond only when a target was absent (No-only responding). Following initial training, subjects were transferred to the opposite response condition. During training the function relating reaction time to memory-set size differed between age groups only with CM practice, replicating age-related effects previously found for extensive CM practice. Response reversal (e.g., Yes-only to No-only) after training led to age-related transfer effects for both CM and VM search. Importantly, the transfer data suggest age-dependent controlled processing effects.

Adolescent↗

PubMed1989

An automatic/controlled processing theory application to training component map reading skills.

An experiment was conducted which explored the applicability of automatic/controlled processing theory to a complex map reading/identification task. Subjects were trained on one component of a map reading task (magnitude estimation based on map-legend colour codes) and then transferred to a full map reading mask. Consistent and inconsistent colour codes were trained. Training with consistent map-legend colour codes resulted in automatic processing of those codes and led to performance that was faster, less variable and less sensitive to memory factors when compared with performance associated with variably mapped colour codes. These data support the view that consistent hierarchical relationships can be utilised to supersede inconsistencies at the individual stimulus level. The results also place constraints on how displays should be built in order to capitalise on hierarchical consistencies held in memory.

Journal Article↗

PubMed1988

The influence of age on consistent and varied semantic-category search performance.

Three experiments examined age-related consistent mapping (CM) and varied mapping (VM) practice effects. In separate experiments, young (age, 19-22), middle-aged (37-50), and older (64-88) adults' performance was examined using semantic-category and letter-based search paradigms. After extensive practice, major age differences occurred in CM search. Young and middle-aged subjects showed near-zero comparison slopes, large reductions in mean reaction times, and substantial reductions in response variability. Although older adults' reaction time decreased with CM practice, the reduction in reaction time, comparison slope, and response variability was small compared with the other groups. In VM search, older subjects were slower than the other age groups, but all groups exhibited similar linear set-size functions, search termination, and comparison-load effects. We concluded that age-associated declines in cognitive performance may be due in large part to the degree with which older adults can acquire or use automatic processes to perform tasks.

Adult↗

PubMed1988