In the mood to forget : paradigmatic and individual differences in remembering and forgetting negative self-relevant memeories

Although forgetfulness is a common and naturally occurring phenomenon, research suggests that it can be intentionally induced using several experimental paradigms. For some individuals, the ability to forget negative thoughts, images, or memories is problematic. That is, the inability to forget may be a source of significant psychological distress (e.g., post-traumatic stress, obsessive-compulsiveness, and depressed mood) that contributes to the maintenance of symptoms of various mental health disorders. The schema-activation hypothesis from Beck’s (1987) Cognitive Theory of Depression suggest that memories should be more readily brought to mind because they are more readily available through associated activation. Thus, negative memories may be difficult to inhibit (forget), for individuals who are depressed compared to non-depressed counterparts. Indeed, suppression effort (the intentional mental effort to not think about something) often leads to an increase in the very cognitive content targeted for forgetting. For individuals who experience depression or dysphoria, suppression is not effective because the negative cognitive content, which is the hallmark the depressed mood state only serves to maintain or exacerbate the mood state. This raises the question of whether there are alternatives to suppression-like paradigms that may be more efficacious for those who are dysphoric or depressed. Investigating the efficacy of induced-forgetting of negative memories may provide researchers and clinicians with additional avenues to explore the therapeutic potential of induced forgetting as an intervention or preventive strategy in combating depressed mood states. The purpose of the present study was threefold: first, this study examined whether individual differences (e.g., mood state) in a person’s ability to call to mind (remember) negative self-relevant memories would affect memory generation time. Second, the implications of differences in mood for the efficacy of two experimental forgetting paradigms – Directed Forgetting (DF) and Retrieval Induced Forgetting (RIF) were explored. Finally, individual differences in mental control (i.e., perceived mental controllability, mental control strategies, and rumination as a coping response) were examined in terms of their ability to predict who would be better at remembering and forgetting. University students (N = 103) with high and low levels of symptoms of dysphoria were asked to generate a set of 32 negative memories using cue words. After rating their memories for clarity and negative valance, each set of memories was subject to either a Directed Forgetting or Retrieval-Induced Forgetting procedure. Participants also completed self-report measures of mental control and rumination. Individuals who were dysphoric were similar to those who were non-dysphoric in the amount of time it took to generate a set of 32 negative memories. These results failed to support the tenets of the Schema Activation Hypothesis of Beck’s (1967) Cognitive Theory of Depression. Subsequent analysis revealed that the act of generating negative memories was mood-inducing, which may have negated the effect of mood on generation time. In terms of the effect of mood on induced-forgetting paradigm efficacy, the analysis yielded several null findings. The insufficient power prohibited the ability to detect small effects. Dysphoric individuals evidenced deficits in forgetting for the directed-forgetting but not the retrieval-induced forgetting paradigm, but only when separate analysis of individual paradigms was undertaken. In this case, the effect of mood on forgetting approached significance for the directed-forgetting paradigm but not the retrieval-induced forgetting paradigm. This suggests that inducing forgetting for those who are dysphoric is more likely to be successful if there is no instruction to “forget.” Finally, it was predicted that poor perceived mental control, a tendency to ruminate, and the use of mental control strategies would correlate with induced-forgetting. Results suggest that individuals who perceive themselves as poor at controlling mental content, and ruminate about their internal experience of sadness are impaired on recall of negative autobiographic memories when asked to forget them. In contrast, mental control variables were not related to the degree of forgetting using retrieval-practice methodology. The results of this study have implications for future research designed to further explore the therapeutic value of induced-forgetting, particularly for the RIF paradigm. That is, the presence of a retrieval-induced forgetting effect for those who are dysphoric could prove to be a beneficial coping strategy to combat unwanted negative memories. It may be important to study the longitudinal value, as well as explore the potential benefits for other psychologically distressing phenomena in which negative memories are a part (e.g., post-traumatic stress). That cognitive factors, such as mental control and ruminative coping, do not share a relationship with degree of forgetting in the RIF paradigm also bodes well in demonstrating a possible therapeutic advantage for RIF compared to DF. Researchers are advised to consider mood and mental control variables in terms of their potential effects on forgetting paradigm efficacy when selecting their methodology in studies of intentional forgetting. This is particularly important when using a university sample of participants. It is often the case with experimental research, that a university sample is used. Given the higher rates of dysphoria and self-reported depressive symptoms that tend to typify university students and therefore, may be higher than in community-based samples, researchers are cautioned to consider the implications of dysphoria on research outcomes when testing induced-forgetting paradigms