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Biomedical subjects

P H Marshall

Publications and source records attributed to P H Marshall.

12 recordsLinked to original sources
PubMed1998

List length and the bizarreness effect: support for a hybrid explanation.

The dual-component distinctiveness and expectation-violation explanations of bizarreness effects were compared to a newly proposed hybrid model in a single experiment investigating the influence of list length and list composition on recall for common and unusual verbal information. Although list composition was determined to be an essential variable, the results suggest that list composition does not influence memory directly as a retroactive organizational or retrieval cue. The results do, however, support the notion that list composition influences memory indirectly by altering intralist expectations. Although the results support neither the dual-component nor the expectation-violation explanation as originally formulated, the results are in keeping with the hybrid model which incorporates both intralist and extralist sources of distinctiveness and an expectation-violating mechanism.

Adult↗
PubMed1998

Knee position error detection in closed and open kinetic chain tasks during concurrent cognitive distraction.

It is important to establish whether presumed differences among varieties of motor responses are manifested in related differences in performance. In order to determine possible functional distinctions between closed and open kinetic chain tasks, participants' performance in the presence or absence of cognitive distraction on an error-detection task was assessed. Individual testing of participants consisted of knee extension and flexion movements to experimenter-defined positions, approximating the 25th, 50th, and 75th percentile of the participants' range of motion on the apparatus. Performance under conditions of distraction was significantly worse than in the absence of distraction. Performance using longer movements was significantly more accurate. No substantial differences were found between closed and open kinetic chain movements. Limitations of this research for the distinction between open and closed chain tasks are addressed, and clinical implications of the effects of distraction are presented.

Adult↗
PubMed1996

Reality monitoring in recovering alcoholics.

OBJECTIVE: The major aim of this study was to provide confirmation of the lack of metamemory deficits found in previous research, and we chose reality monitoring as our empirical arena. Reality monitoring is defined as the ability to distinguish between memories for events that have actually occurred and memories for imagined events, with actual events characterized by higher levels of sensory-perceptual information. Further, since detoxified alcoholics have demonstrated perceptual, especially visual, deficits, this study examined whether that would have an adverse effect on reality-monitoring performance. METHOD: Young adult, male, detoxified alcoholics (n = 60) and appropriate controls (n = 29) participated in reality-monitoring tasks using, primarily, either visual or verbal information. RESULTS: There were no significant differences between the two subject groups on either of the reality-monitoring tasks, and no significant contributions from descriptive, background or educational variables on these tasks. CONCLUSIONS: Convergent validation of the previous finding of no metamemory deficits with young, male, recovering alcoholics was obtained. The results also were discussed briefly in the context of alcoholics' quality of memory in therapeutic situations.

Adolescent↗
PubMed1985

Spatial location judgments as a function of intention to learn, and mood state: an evaluation of an alleged automatic encoding operation.

An assessment of the Hasher and Zacks (1979) conceptualization of the automatic nature of the acquisition of spatial location information was made in the context of manipulations of subjects' intention to learn and mood state. The Velten (1968) mood induction procedure was used to establish depressed and nondepressed subjects. Half of each group was then presented with a matrix of geometric forms under instructions to learn the location of the forms (intentional) or to evaluate the pleasantness of the array (incidental). Subsequent tests of spatial location performance found no differences as a function of subjects' mood state, but did find a strong effect for instructional condition. The superior performance of the intentional subjects raises questions about the automatic nature of the encoding of spatial location.

Adult↗
PubMed1978

Age differences in verbal mediation: a structural and functional analysis.

Five experiments were conducted to investigate potential structural and functional differences in verbal mediators given by young and elderly adults to CVC material. Experiment 1 found no significant differences in the complexity and flexibility of mediator formation by the two age groups. Experiment 2 replicated these findings using a different sample and task, and different materials. Additionally, this study also indicated a significant rank order correlation for the particular types of mediators used. Experiment 3 indicated that under some situations young subjects may be able to discriminate young from old mediators while Experiment 4 showed that younger subjects had no preference for which mediator would be most helpful to them in a learning task. Experiment 5 found that, in a paired associate learning task, young subjects learned faster the mediators given by other young subjects. The data were discussed in terms of current methodolical practices and in terms of localizing age-related memory deficits in structure or process variables.

Adult↗
PubMed1977

Short-term memory factors in oral retention.

Study or exploration time and retention interval duration between orignal-form exploration and test-form exploration were varied to assess the effect of these two variables on performance accuracy on an oral stereognostic memory task. Irregularly shaped, four-sided plastic forms were used as stimuli. Retention performance improved significantly with an increase in exploration time of up to 15 seconds, but was not effected by delays in testing of up to 60 seconds. Clinical and theoretical implication for oral stereognosis are discussed.

Adolescent↗
PubMedDate not supplied

Age related factors in motor error detection and correction.

Two preliminary investigations were conducted on the error detection and error correction capabilities on a simple motor task of young, middle-aged and elderly adults. The error detection task assessed the subjects' ability to discriminate which of two test movements was the same as a previously presented criterion movement. The error correction task required subjects to correct an erroneous movement so that it was the same as a previously experienced criterion movement. Error detection performance increased for all age groups as the discriminability of the incorrect alternative on the test trial increased, but the middle-aged and elderly subjects demonstrated inferior overall performance relative to the younger subjects. Older subjects gave higher absolute error correction scores especially at the low error discriminability level, and the younger subjects did not show the negative correction bias (algebraic error) as suggested by the performance of the two older groups. The data were discussed in terms of Adams' closed-loop theory of motor memory.

Adolescent↗