In a past feature we looked at an article by Elizabeth Bowman, M.D. which reviewed the research on corroboration of recovered memories. In this feature we examine a second article by Dr. Bowman which reviewed the literature on suggestibility and delayed memory.
Dr. Bowman begins this article by reviewing the literature on hypnosis and memory. She notes that patients with dissociative disorders are highly hypnotizable. Much research has demonstrated that highly hypnotizable subjects sometimes create "pseudomemories" when such memories are explicitly suggested to them.
She continues to summarize the following points from research on hypnosis and memory:
- Hypnotic subjects report more accurate and inaccurate information than awake subjects do. Hypnosis enhances the confidence subjects have in their memories, regardless of their accuracy. Subjects cannot always distinguish between memories which they have always had and new memories recently recovered under hypnosis.
- Fabricated memories can be created when directly suggested by the hypnotist during age regression.
- Hypnotic age regression does not appear to increase the accuracy of childhood recall. The impact of hypnosis on the reliability of later memory depends on the type of question asked. Open-ended questions cause less memory contamination than closed-ended, leading questions. Some pseudomemories suggested by hypnosis do not persist after the hypnosis. Pseudomemories reported during hypnosis do not replace real memories; and they are frequently not believed by the subject.
- There are differences between lab studies and studies with abuse survivors. Memories recovered in hypnosis have been corroborated in the majority of cases in some studies. In addition to the above points from research on hypnosis and memory, she summarizes the following points from research on hypnotizability and memory:
- High hypnotizabiliy is a more important factor in the production or pseudomemories than whether there was a hypnotic induction.
- High hypnotizablity and hypnosis together produce the highest rates of pseudomemories. Bowman then explores issues surrounding the accuracy of very early memories. Studies have found that most people recall events dating back to age 3 1/2, but some people recall events - such as the birth of a sibling - dating back to age 2. Studies have found that full verbal recall of abuse is rare before 3 years of age. Accurate behavioral memories, however, are sometimes available for events as early as one year of age. There appears to be a dual memory system in early childhood. Behavioral and affective memories exist from birth onward. These are poorly organized and tend to be evoked by situations and emotions. Some studies have found that preverbal abuse memories can survive the transformation to verbal memory and be reported later.
- Fictitious early memories can be created by hearing family stories or by the direct suggestions of adults. Fictitious memories of a mildly unpleasant event (such as being lost in a mall) can be created in children and adolescents. This process cannot induce similar memories of more unpleasant events (such as receiving an enema).
Therapists are urged to be cautious concerning the accuracy of early childhood memories, especially memories from before age three. While "body memories" may represent true non-verbal memory, they may also be "a part of the fantasies of highly hypnotizable persons." (Bowman, 1996 p.237)
- Source monitoring and reality monitoring Numerous studies on eyewitness testimony have shown that some subjects incorporate information learned after the event into their memory of the event. Other studies show that subjects often mix-up memories of things they are told about with pictures they have been shown. These types of errors are termed "source misattribution."Other studies have shown that as many as 39% of adults "confuse memories of simple acts that they imagined with things they actually did." (Bowman, 1966, p. 237) This is "reality misattribution." Children are even more prone to this type of error. Neither adults nor children confuse things they imagined doing with things actually done by other people. Some people are able to review their memories and accurately determine their source, sometimes based on the quality of details in the memory. Memories tend to be rich in sensory material; while imagined events include more thinking and reflecting; and dreams lack those cognitive aspects. Bowman warns therapists to avoid asking clients to guess about what might have happened to them. She also warns against using "imaginative visualization" techniques to help clients fill-in memory gaps.
