Date of Award

1997

Document Type

Thesis

Publisher

Edith Cowan University

Degree Name

Bachelor of Arts Honours

Faculty

Faculty of Health and Human Sciences

First Supervisor

Don Thomson

Abstract

Although stress at the encoding stage of eyewitness memory has been studied in depth in the literature, little is known about the recall stage. Stress effects on retrieval were investigated in two experiments to examine its impact on recall, repeated testing, and accuracy. Stress was manipulated by evaluative threat and time pressure at either immediate and/or delayed recall (20 minutes) in four experimental conditions in Experiment I. Participants were 62 undergraduate students from Edith Cowan University. A series of 40 pictures, five to a slide, were shown by overhead projector at the rate of 20 seconds per slide. There were no differences between groups for reminiscence, i.e. all groups recalled new items at delay. At immediate recall groups did not differ for the number of items recalled, however at delay the immediate stress delayed no stress group showed moderate hypermnesia and differed significantly from the other groups, who showed a decrease in recall. All groups made significantly more errors at delay, and there were no differences between groups for the number of errors made. In Experiment 2, participants were 65 metropolitan bank staff members assigned to the same experimental conditions as in Experiment 1, who were shown a series of 12 slides depicting a handbag snatch, at the rate of 5 seconds per slide. Stress was manipulated by time pressure and by emphasising the importance of accuracy. All groups showed reminiscence, but the stress at immediate recall groups showed significantly higher reminiscence than the no stress at immediate recall groups. There were no differences between groups for immediate recall, but the immediate stress groups remembered significantly more at delay (hypermnesia). The no immediate stress participants did not differ from immediate to delayed recall No differences between groups were found for overall errors. Separate chi-square analyses of errors for offender, victim and scenario at immediate and delayed recall showed that the stress at both recall group made significantly less errors about the offender at delay. The major finding in both studies was that stress does not appear to have an adverse effect on recall, and in some cases may have a facilitatory effect if manipulated at immediate recall.

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