越努力去忘就越能忘记吗？——情绪材料定向遗忘的“剂量效应”

The Harder You Forget, the More You Forget?——The “Dose Effect” of Directed Forgetting for Emotional Materials

采用项目法定向遗忘研究范式,在两个实验中分别使用情绪性语词和图片材料,考察主观努力程度影响情绪材料定向遗忘的心理机制。研究采用2(语词或图片情绪效价:正效价/负效价)×2(指示符:记住/忘记)×3(主观努力程度:高/中/低)的被试内设计。结果表明,正效价词在三种努力程度忘记条件的再认率无差别,越努力去忘记负效价词,反而越能记住;正负效价的图片材料都呈现出越努力去忘记反而越能记住的特点。以上结果表明,语词与图片分别适合有意识加工和无意识加工,记住指令导致对情绪性语词和图片的选择性复述,部分符合选择性复述/被动衰退理论;不同努力程度的忘记指令引发了对情绪性语词和图片的主动抑制,符合注意抑制/执行控制理论。

Directed forgetting refers to retrieval impairment caused by "forget" command during the study phase. Many factors affecting directed forgetting have been studied in order to understand the processing mechanism involved. However, no research has yet examined the influence of subjective effort intensity on directed forgetting. This study used an item-method directed forgetting paradigm, using emotional words and pictures in two experiments, to investigate the psychological mechanism by which subjective effort intensity affected the directed forgetting for emotional materials.In Experiment 1, emotional words were used as stimuli in a 2 × 2 × 3 within-subjects design, with emotional valence(positive, negative), instruction(remember, forget), and effort intensity(20%, 60%, and 100%;corresponding low, medium, and high respectively) as the independent variables, and recognition rate and directed forgetting effect for emotional words as the dependent variables. In the study phase, emotional words were followed by the instructions to "remember" or "forget" with different effort intensities. The participants were instructed to process the emotional words according to the instructions and effort intensities. In the test phase, the participants were asked to recognize the old and new words. The results of the experiment showed that, regardless of positive or negative words, the harder it was to remember, the better the recognition rate was. However, there was no difference in the recognition rate of positive words in the three effort intensities for forgetting, and the harder it was to forget the negative words, the more one could remember. In Experiment 2, emotional pictures were used as stimuli, and the experimental design and experimental procedure were the same as Experiment 1. The results suggested that the directed forgetting effect for emotional pictures was generally not significant. Further analysis found that this was because subjects could not effectively forget the TBF pictures(especially positive TBF pictures) under the conditions of high and medium effort. By contrast, under the condition of low effort, it was most beneficial to the intentional forgetting of negative picture. Therefore, for the picture stimuli, regardless of positive or negative pictures, the higher the effort, the worse was the directed forgetting effect, that is, the harder it was to forget, the more one could remember.The results of the above two experiments indicated that subjective effort intensity affected the intentional forgetting for emotional materials. Specifically, for positive words the more efforts were tried to forget, the more one could forget;whereas for negative words and pictures, the harder one tried to forget, the more difficult it was to forget. This was related to the different processing methods for words and pictures, as well as the respective suitability for conscious processing and unconscious processing. In this study, the instruction to "remember" led to the selective repetition of emotional words and pictures, which accorded with the theory of selective repetition/passive decline;However, the instruction to "forget" with different effort intensities caused the active inhibition of emotional words and pictures, and this was in line with the theory of attentional inhibition/executive control.