項目指示遺忘效果的行為與事件相關電位研究

Behavioral and Event-Related Potential Studies of Item-Method Directed Forgetting Effect

謝良典(Liang-Tien Hsieh)

指導教授 ： 鄭仕坤

國立中央大學/理學院/認知與神經科學研究所/碩士(2006年)

摘要

摘要

這篇論文主要的研究目的在於利用電生理以及行為指標來探討項目指示遺忘效果(Directed Forgetting Effect)的認知歷程及其神經機制。在項目指示遺忘作業(Item-Method Directed Forgetting Task)之中,學習階段每一個出現在螢幕上面的學習刺激後面可能會跟隨著『記住(R-cue)』或者是『忘記(F-cue)』的指示，其目的在要求受試者分別去記住或者是去忘記某一個學習刺激。在之後的測試階段中，所有在學習階段出現過刺激以及在整個實驗過程中沒有出現過的刺激會隨機的出現在電腦螢幕上，而受試者被要求去再認出在學習階段中出現過的所有學習刺激；不論此刺激在學習階段是要求受試者去記住或者是去忘記。實驗二藉由記錄受試者在執行項目指示遺忘作業的學習以及測試階段的腦波訊號，進一步的去探討項目指示遺忘效果的認知及神經機制。此外，為了對實驗二所得到的電生理結果提供一個『基準比較(Baseline Comparison)』，實驗一要求受試者執行『簡單再認作業(Simple Old/New Recognition Task)』，並且紀錄受試者在簡單再認作業之中學習以及測試階段的腦波，而其電生理資料也與實驗二的電生理資料做比較；進一步的去探討項目指示遺忘效果的認知及神經機制。

除了實驗一以及實驗二的電生理實驗，此篇論文也執行了一系列的行為實驗去進一步的探討在實驗二裡面所觀察到的電生理結果。在實驗三裡面，學習階段的『記住』以及『忘記』的指示出現在學習刺激之前，其目的在探討在項目指示遺忘作業中受試者對於學習刺激的登錄歷程。在實驗四中，除了在學習階段的項目指示遺忘操弄，測試階段時受試者被要求去執行『來源記憶作業(Source Memory Task)』;也就是說受試者除了再認出在學習階段出現過的學習刺激以外，他們還必須要去判斷此刺激在學習階段時是被要求去記住或者是去忘記，其目的在進一步的探討受試者在項目指示遺忘作業中的記憶提取歷程。最後，在實驗五當中，受試者在測試階段時被要求去執行兩種不同的『記憶排除作業(Memory Exclusion Task)』，其目的也是進一步的去探討受試者對於『去記住的刺激』以及對『去忘記的刺激』的記憶提取歷程。藉由這一系列的電生理以及行為實驗，期望能夠對於項目指示遺忘效果的認知及神經機制有更清楚的了解。

關鍵字

項目指示遺忘效果 ； 事件相關電位

並列摘要

Abstract

Two electrophysiological studies and a series of behavioral experiments were conducted to investigate the cognitive/neural mechanisms underlying the item-method directed forgetting effect. For the two electrophysiological studies, brain waves were recorded when subjects engaged in the simple old/new recognition task and the directed-forgetting recognition task respectively. In the study phase of the item-method directed forgetting task, each study item was followed by either a “R” or a “F” cue, which instructed the subject to remember or to forget the preceding item respectively. In the following test phase, subjects were presented with all the study items intermixed with unstudied new items. Subjects were instructed to identify all study items, regardless of whether these items had been instructed to be remembered or to be forgotten in the earlier study phase.

For both the simple recognition task and the directed forgetting task, ERPs were recorded in the study and test phases. The ERPs recorded during the test phase were sorted and compared according to the response categories the eliciting stimuli belong to (i.e., hit, miss, false alarms, and correct rejections in the simple recognition task; hit and miss to to-be-remembered and to-be-forgotten items, false alarm, and correct rejections in the directed forgetting task). For the ERPs recorded at study, these waveforms were also categorized according to the subsequent response the study items elicited in the subsequent test phase (i.e., subsequently remembered and forgotten items).

Following these two electrophysiological studies, a series of behavioral studies were conducted to clarify the properties of the cognitive processes involved in the item-method directed forgetting effect. These behavioral studies were (a) pre-cued item-method directed forgetting task, in which the remember and forget cues were presented before, rather than after, the presentation of the study items, (b) item-method directed forgetting task with source judgments, in which subjects were required to identify whether a recognized item had been followed by a R or F cue in the earlier study phase; (c) item-method directed forgetting with exclusion tasks, in which the target items could be to-be-remembered or to-be-forgotten items. It is expected that these ERP and behavioral results would advance our understanding of how people remember and forget the episodes they have experienced.

並列關鍵字

Item-Method Directed Forgetting Effect ； Event-Related Potential

參考文獻

Reference List

Allan, K. & Rugg, M. D. (1997). An event-related potential study of explicit memory on tests of cued recall and recognition. Neuropsychologia, 35, 387-397.

Basden, B. H., Basden, D. R., & Gargano, G. J. (1993). Directed forgetting in implicit and explicit memory tests: A comparison of methods. Journal of Experimental Psychology: Human Learning and Memory, 19, 603-616.

Bjork, E. L., & Bjork, R. A. (1996). Continuing influences of to-be-forgotten information. Consciousness and Cognition, 5, 176-196.

Cohen, J.D., Servan-Schreiber, D. (1992). Context, cortex, and dopamine: a connectionist approach to behavior and biology in schizophrenia. Psychol. Rev., 99, 45-77.