负性情绪材料的定向遗忘及心理机制

采用项目法定向遗忘的研究范式，在两个实验中分别采用文字和图片材料考察了情绪性记忆定向遗忘的效果及其心理机制。实验中采用了中性和负性两种实验材料，设置了两种记忆指令出现时间（2秒后提示和5秒后提示），相对于中性材料，被试更不容易忘记负性材料。记忆指令出现的时间只影响图片材料的定向遗忘。研究表明负性情绪会干扰定向遗忘，选择性编码理论可以解释情绪性文字材料的定向遗忘，而抑制理论更能解释情绪性图片材料的定向遗忘效应。

Directed Forgetting of Negative Memories and Its Mechanisms

There are two distinct methods of directed forgetting: the item-method and the list-method. In the list-method researches, directed forgetting effects have unanimously been attributed to the inhibition at retrieval. In contrast, in the item-method studies, two controversial accounts, the selective encoding and the inhibitory control, have been used to explain the directed forgetting effects. In the recent years, there is a growing interest in the directed forgetting of emotional memories. Although a bunch of researches have been done on this project, no consistent findings have been obtained concerning whether the participants show any directed forgetting effect for emotional memories. Forty-four undergraduates and graduate students participated in Experiment 1. Twenty-four neutral double-character words and twenty negative ones were included in the materials which were randomly distributed to two experimental conditions, two-second interval and five-second interval. The experiment was divided into three separate parts. The subjects were first asked to learn forty-four words, and then they were instructed to carry out a distraction task followed by a recall task in which the participants were required to recall as many as they could from the items learned. The same procedure was applied to Experiment 2, in which neutral and negative pictures were used as materials instead to explore the directed forgetting of pictures. A three-factor analysis of variance (ANONA) was performed after the experiment with the material type, the length of the interval and the type of the instruction as within-subject variables.The results of Experiment 1 showed that negative words could be forgotten in directed-forgetting just like neutral ones; at the same time, it was found that the interval between the items and the cue did not influence directed forgetting. Likewise, in Experiment 2 negative pictures could also be forgotten. Interestingly, it was found that the different intervals between the picture and the cue did influence the effect of directed forgetting. These results confirm that negative memories can be forgotten in directed-forgetting. In addition, the results indicat that the mechanism of directed forgetting in words can be better explained by selective encoding, while the mechanism of directed forgetting in pictures is more likely to be accounted for by the inhibitory control theory.