Geraerts, E., McNally, R., Jelicic, M., Merckelbach, H., & Raymaekers, L. (2008). Linking thought suppression and recovered memories of childhood sexual abuse. Memory, 16, 22-28.

Background

            This study looks at how people remember and forget extremely distressing events. It focuses on the authenticity of repressed and recovered memories of childhood sexual abuse (CSA), which the authors define as “physical sexual contact ranging from fondling to penetrative acts until the age of 12.”  Past research has assumed that CSA is in fact a traumatic event and would therefore be encoded very well and hard to forget.  However, some researchers have found that some CSA that a person believes they have repressed is actually a false memory, a memory for and event that one truly believes they have experienced, but in actuality they have not.  Other researches suggest that some recovered memories are not truly recovered because they were never actually repressed.  This can be seen in victim that did not realize the impact of their abuse at the time so they do not view it as a traumatic experience.  If they do not think about it for a long time and then something reminds them of it they view it as a recovered memory.  However, the authors point out that not thinking about something is not the same thing as not being able to remember it.

            There are two types of recovered memories, those that gradually come to a person in a therapy session, and those that spontaneously occur outside of therapy after something reminds them of it.  The idea behind recovered memories is that those that have them experience lack of conscious recall.  Therapists suggest that this is due to a special mechanism the person develops, such as dissociation or repression, preventing the memory from entering into their conscious awareness.  In contrast, a survey of non-clinical participants showed that the individuals attributed their recovered memory to intentional attempts to forget a memory in order to avoid thinking about the traumatic experience. 

            In order to understand how people suppress their thoughts and who is more likely to do so, the authors adapted Wegner’s (1994) thought suppression paradigm, using autobiographical thoughts of a positive event and an anxious event as the target thoughts.  This study wanted to know whether people that spontaneously recovered memories of CSA were better able to suppress positive and anxious autobiographical thoughts compared to people that recovered their memory in a therapy session, people that had continuous memories (they had never forgotten their abuse), and to a control group that had no history of sexual abuse.  The authors predicted that the people with spontaneously recovered memories would be better at suppressing the target thoughts than those in all the other groups.  If this is correct it may help to understand why the people with spontaneously recovered memories tend to think they have repressed the memory, when in fact they have just not thought about it in a long time.

Method

         The authors recruited participants through advertisements in the paper, telling them the research was related to CSA and memory.  There were four groups in the study, the first was the spontaneously recovered memory group which had 30 (21 women) participants who said that they had previously forgotten and then spontaneously recalled memories of CSA outside of a therapy session.   The second group was the recovered in therapy group that had 30 (24 women) participants who said that they had recovered their memories of CSA during a therapy session.  The third group was the continuous memory group that had 30 (22 women) participants who said that they had never forgotten their abuse. The last group was the control group that had 30 (20 women) participants that had no history of sexual abuse as a child or an adult.

Materials

            In the thought monitoring task participants used a joystick to indicate when a target thought came to mind.  The authors defined and intrusive thought as a “spontaneously occurring” thought about either of the target thoughts, positive or anxious autobiographical event.  Then, in order to understand the long-term effects of thought suppression, participants recorded each time they experienced a target thought in a diary for 7 days. 

Procedure

         This study had two stages that corresponded to the two target autobiographical events, and each stage then had three periods.  The first stage was for either the positive or anxious target event.  The first period was the imagining period in which the participants at 2 minutes to select and imagine the most positive and most anxious event they had experience in the last two years.  During this period participants were to rate the valence (0􏰁very negative, 10􏰁very positive) and the clarity/vividness (0􏰁not at all clear/vivid, 10 very clear/vivid) of their memory for each target thought, as well as the distress (0􏰁not at all distressing, 10􏰁extremely distressing) and anxiety (0􏰁not at all anxious, 10􏰁extremely anxious) in relation to the thought.  The next period was the suppression period where participants were told to suppress the target event, and to monitor their thoughts using a joystick for 2 minutes. The third period was the expression period where for 2 minutes the participants were allowed to think about anything, including the target thought, but were told to monitor those thoughts with the joystick.  After the expression period, the next 5 minutes consisted of a mathematical filler task that was completed by all the participants.  The second stage the exact same as the first stage, but the other target thought was used.  After both stages the participants were instructed on how to do the 7-day diary.

Results

            When selecting the autobiographical thoughts the four groups did not differ in terms of their valance ratings of the target events.  Not surprisingly, the participants reported more distress when recalling the anxiety target than with the positive target.  The study also found that the groups did not differ in their reports of clarity/vividness ratings of both the targets. 

            With regards to the suppression period, the post-suppression rebound effect, and the intrusions during the 7-day period, the frequency of occurrence of the anxious target thought differed across groups, but the frequency of the positive target thought did not.  A post hoc Least-significance-Difference (LSD) test was run, finding that participants with spontaneously recovered memories had significantly fewer occurrences of the anxious target thought than all three other groups supporting the author’s theory. 

            The authors define a rebound effect as an increase in frequency of target thoughts from the suppression period to the expression period. A LSD test showed that those with spontaneously recovered memories showed a smaller post-suppression rebound effect than the other groups.

Discussion

Unlike past research, this study showed a better ability to suppress negative memories in the short term and did not lead to a higher frequency of intrusions in the long term.  In other words, people that had spontaneously recovered memories showed no rebound effect for the anxious target event after 7-days.  This supports the idea that that people reporting recovering a repressed memory have not always actually repressed that memory.

The finding of this study that those with better ability to suppress a memory are those that have spontaneously recovered the memory, fit with the non-clinical survey where 23% of the people attributed their lack of continuous memory of a traumatic event to intentional strategies to forget that memory.  Likewise this study and research previously done by the authors show that people who recover memories are more prone to source-monitoring. The authors found that those that gradually recovered a memory in therapy could not be corroborated as often as those spontaneously recovered memories or had never forgotten the memory.  They suggest this may be due to a combination or the therapist’s suggestions and the individuals intrinsic source monitoring.  Lab studies support this evidence for source monitoring by showing that adults with recovered memories had higher rates of false recognition for neutral and trauma related words than those with continuous memories. 

One possible limitation the authors noted was that they did not include a non-suppression control group, meaning that those that spontaneously recovered memories may be more likely to be compliant in following instructions.  However, according to the Marlowe-Crowne Social Desirability Scale, there was no significant difference in the other three groups anyway.  Previous research suggests that forgotten CSA memories can be upsetting without actually being terrifying to the victim, but thought suppression is most likely used as a way to avoid thinking about the memory any way.  However, not having anything to remind a victim of what happened to them is not the same think as intentionally forgetting the CSA.  If an individual forgets a prior memory, it may lead to the illusion that they have repressed that memory.  This suggests that the recovered memory may never have been lost at all, and the authors suggest further research needs do be done on this idea.