Memory Deficit In Moderately Depressed University Students

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Doctor of Philosophy


The factual status of a hypothesized memory deficit in mildly to moderately depressed undergraduates is unresolved by a literature review. Three studies of 20 depressed and 20 nondepressed undergraduate volunteers who met Beck Depression Inventory and other screening criteria were thus conducted to examine sensory memory (SS), short term memory (STS), and long term memory (LTS).;A modified Sperling task was used to study SS, where subjects viewed 3 by 4 letter-digit arrays, and then reported items in the cued row or whole display. Aside from a few minor qualifications, no group differences were observed in the partial or whole report conditions suggesting unimpaired SS.;STS was studied in a digit span task where strings of 6 to 12 digits were recalled after a variable unfilled delay. For strings of moderate size a deficit was observed at 20 and 30 seconds delay but not at 1 second, suggesting impaired retention, possibly due to rehearsal.;In the final study a delayed recall task was used to examine LTS. Subjects free recalled a 30 item list 2.5 hrs after learning items to a 70% criterion. The group difference in the number of items forgotten approached significance suggesting the possibility of impaired retrieval. No other group differences were found in the study's other sub-tasks (incidental recall, immediate recall, number of trials to criterion).;The above results suggest that in mildly to moderately depressed undergraduates, SS and its readout are intact, STS retention is impaired, and LTS retrieval may be impaired. Studies of similar subjects performing other tasks containing a large memory component are consistent with the above conclusions. One possible explanation of the findings assumes that depression-induced rumination interferes with rehearsal. Another possibility is that motivation selectively affects memory by reducing available processing resources. A more explicitly formulated notion, developed by Hasher and Zacks which appeals to effortfulness and automaticity, is described.;Implications of the findings for Beck's and Seligman's theories were discussed. Practical implications for psychotherapy, education, and research methodology were also considered.

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