In my previous post, I looked at the first three sins of memory using Harvard University psychology professor Daniel Schacter’s book The Seven Sins of Memory as a guide. In this post I’ll look at the remaining four sins.
Misattribution: attributing a memory to an incorrect source
“Most people, probably, are in doubt about certain matters ascribed to their past. They may have seen them, may have said them, done them, or they may only have dreamed or imagined they did so.” –William James, The Principles of Psychology, Volume 1 (1890). Chapter X. The Consciousness of Self
In 1975 Australian psychologist Donald M. Thomson went on television to discuss the psychology of eyewitness testimony. The day after the broadcast, Thomson was picked up by local police, who told him that the previous evening a woman who was raped and left unconscious in her apartment had named Thomson as her attacker. Fortunately, Thomson had a watertight alibi, having been on television at the time of the attack and in the presence of the assistant commissioner of police. It turned out the victim had been watching Thomson on television just prior to being attacked, and had confused his face with that of her attacker.
Misattribution is attributing an event to something with which it really has no connection or association. Information is retained in memory, but the source of the memory is forgotten. This is also what happens when you mix up details from two separate events and combine them into one cohesive memory. According to some theories of memory, misattribution errors are a result of failed memory binding – the binding together of individual parts of a memory into one cohesive unit. Your recollection of an event wasn’t appropriately tied to your recollection of the source of the event.
While most misattributions are not so dramatic as that of Donald Thomson, In 1998 Gary Wells at Iowa State University and his colleagues identified 40 different US miscarriages of justice that relied on eye-witness testimony. Many of these falsely convicted people served many years in prison, some even facing death sentences. Some examples of misattribution that have been studied in the lab include:
Misattributing the source of memories. People regularly say they read something in the newspaper or online, when actually a friend told them about it or they read it someplace other than where they claim they did. In one study, participants with “normal” memories regularly made the mistake of thinking they had acquired a trivial fact from a newspaper, when actually the experimenters had supplied it. In another experiment, published in Psychological Science in 2010, researchers found that people who had watched a video of someone else doing a simple action – shaking a bottle or shuffling a deck of cards, for example – often remembered doing the action themselves two weeks later. Sometimes an idea or memory is attributed to ourselves that actually belongs to someone else. This is a common source of unintentional plagiarism. In one early study, people were asked to generate examples of particular categories of items, like species of birds. It was found that people, without realizing, plagiarized each other about 4% of the time. Later studies found rates as high as 27% using different types of tasks.
Misattributing a face in the wrong context. This is what happened to Donald Thomson. Studies have shown that memories can become blended together, so that faces and circumstances are merged.
Misattributing an imagined event. In one experiment, participants were asked either to imagine performing an action or actually asked to perform it, such as breaking a toothpick. Sometime later they went through the same process again. Later still, they were asked whether they had performed that action or just imagined it. Those who imagined the actions more frequently the second time were more likely to think they’d actually performed the actions the first time. The experiment demonstrated how easily our memory can transform fantasy into reality. Even something as simple as imagining a childhood event can convince a person that it really occurred
Suggestibility: implanted memory from others
Suggestibility results from outside information being absorbed and incorporated into the memory of an event. These false memories can be implanted as a result of leading questions, comments, or suggestions when a person is trying to recall a past experience. For example, you may remember wearing a black skirt to a party a month ago, but if someone insists that you were wearing a red skirt, it may alter your memory. According to Daniel Schacter, the following are six different types of questions that can illicit a false answer or inaccurate memory:
1. Assumptive Question. This bases the question on an assumption. “How much will the price of gas go down next month?” assumes that the price will go down.
2. Linked Statement. This links two different items together and does not provide the same information for both items. Asking “Would you prefer to live in Clinton or Terre Haute where the crime rate is high?” doesn’t mention anything about the crime rate in Clinton. You can also put something else of significance within the question (note the social coercion in this statement): “What do you think about Larry Jackson? Many people are opposed to him.”
3. Implication Question. Asking questions that gets the other person to think of consequences or implications of current or past events links the past with the future in an inescapable chain of cause-and-effect. “If you stay out late tonight, how will you remain awake at work tomorrow morning?”
4. Asking for Agreement. This is typically the closed question that requires either a “yes” or “no” answer, making it easier for the person being asked to say “yes” than “no”. “Do you agree that we need to save the whales?”
5. Tag Question. These usually involve short phrases that end in a short question that is often negative. Because the questions are tagged onto the end of statements, they effectively make a command look like a question. “You are coming to the very important LSS meeting, aren’t you?” “That’s a good thing to do, isn’t it?”
6. Coercive Question. The context or tone of the question results in either an implicit or explicit coercion. In the question “How can you say that you will not be there?” the questioner implies negative consequences for not attending. In the question “How can you say you won’t come?” the questioner implies that there is no good reason for you not coming.
The tendency of elderly adults to rely on general familiarity in storing memories leaves them particularly vulnerable to false memories. This makes them fertile ground for scammers and other con artists. For example, scammers often call elderly individuals, saying things like “The check you sent us doesn’t quite cover your balance, and we’ll need you to send in another.” Doubting their memories, elderly victims often comply.
As noted in my previous post, critics of repressed memory therapy maintain that many therapists are not helping patients recover repressed memories, but are suggesting and planting false memories of alien abduction, sexual abuse, and satanic rituals. Studies in the suggestibility of children indicated that there were pronounced age-related differences in suggestibility, with preschool children being particularly susceptible to misleading suggestions. Early studies on which this conclusion was based were criticized on several grounds (e.g. unrealistic scenarios, truncated age range). While these studies on which this conclusion was based were criticized on several grounds (including unrealistic scenarios and truncated age range), newer studies that have addressed these criticisms, however, have largely confirmed the earlier conclusions. These studies indicate that preschool children are disproportionately vulnerable to a variety of suggestive influences. The studies also appear to show that while young children are often accurate reporters, suggestive questioning not only distorts children’s factual recall, but has a strong influence on their interpretation of events.
The day may come when it’s possible to physically implant memories in the human brain. Using a technique called optogenetics, Nobel laureate and neuroscientist Susumu Tonegawa and a team of MIT researchers earlier this year implanted a false memory into a mouse’s brain. To do that, they manipulated individual cells in the mouse hippocampus, the part of the brain responsible for memory formation, to make them responsive to light.
Several mice were placed in a chamber glowing with reddish light and allowed to explore. The next day, they were placed in a second chamber and given electric shocks on their feet to encode a fear response. Scientists also shone light into their brains, activating memories of the first chamber. When the mice were placed back in the first chamber, they froze, expecting shocks that never came.
Bias: distortion based upon knowledge, beliefs, and perspective
Memory bias is a cognitive bias that either enhances or impairs the recall of a memory (either the chances that the memory will be recalled at all, or the amount of time it takes for it to be recalled, or both), or that alters the content of a reported memory. If different people observe the same object or event, they will describe it from different different perspectives. In and example used by Schacter. he notes that four people might describe the movie The Wizard of Oz in different ways based on their interests:
1. The young child will tell the story, listing the sequence of events (not necessarily in the right order).
2. The emotional child will explain that the movie was very scary with witches and wizards and flying monkeys.
3. The adolescent will explain the special effects in the movie.
4. The intellectual will identify the themes of the movie.
A study by Dr. Carey Morewedge from Harvard University and colleagues does an excellent job of demonstrating how memory bias works. In the study, 62 subway passengers were randomly allocated to one of three groups. Each was asked to describe a time in the past when they had missed the train, but in subtly different ways:
- Free recallers were asked to describe any instance.
- Biased recallers were asked to describe the worst instance.
- Varied recallers were asked to describe any three instances.
Participants then indicated how happy or unhappy they were on those occasion(s). The results showed that people in both the “free recall” and “biased recall” groups remembered equally depressing times when they had last missed the train. This suggests that when trying to recall a past incidence of a single event, people will naturally recall the worst instance, whether they’re trying to or not. But participants in the “varied recall” group were more positive, suggesting that out of the three events they had recalled, at least one of them was positive. Recalling more than one event, then, makes it more likely that at least one of them is more positive.
After being primed with memories of past experiences of missing the train, participants were then asked to rate how unhappy they would be if they were to miss the train today, testing how memory bias affected their prediction of their feelings in the future. The free recallers made the worst prediction about how they would feel in the future, significantly worse than the varied recallers and the biased recallers. The free recallers and biased recallers were both remembering past experiences that were equally bad, but the biased recallers made the lowest prediction. The researchers concluded that when people are explicitly asked to recall the worst event, they’re aware that it’s the worst event. When people are allowed to recall any event they like, they still recall the worst event, but don’t realize they’ve done so. Because of this, those in free recall make much worse predictions about how they will experience the same event in the future.
Two subsequent studies by the same authors replicated these findings. In the first study, people demonstrated the memory bias when trying to predict positive events in the future, demonstrating that free reign people naturally recall an especially positive example of a particular event. then go on to make much more positive predictions about the emotional effect on them of the same event in the future. The second study extended the same findings to a more natural situation where one group wasn’t asked to recall anything when making a prediction about how they would experience an event in the future. People still demonstrated the same memory bias for predicting future events. Even when not specifically prompted to access past events, people still display the same bias.
False memories due to bias usually result from a desire to reduce psychological discomfort by having one’s thoughts and memories remain consistent. People tend to rely on inference in a wide variety of situations. Studies show that people also infer they’ve seen an event’s cause when they’ve really only seen its effect. People will also remember that they felt a particular way in the past that coincides with how they feel in the present, or even that they were worse off many years ago to make themselves feel better about where they are now. Other things that can bias memories include:
- Beneffectance: the tendency to believe the past glories were the result of our actions, while past disgraces were someone else’s fault.
- Conservatism or Regressive Bias: the tendency to remember high values and high likelihoods lower than they actually were and low ones higher than they actually were.
- Consistency bias: the tendency to remember past attitudes and behavior as resembling your current attitudes and behavior.
- Egocentric bias: the tendency to recall the past in a self-serving manner, like the fish you caught as bigger than it was or the grades you received were higher than they were.
- Hindsight bias: the tendency to think that we could easily have predicted past events when in fact we can’t.
- Illusion-of-truth effect: the tendency to identify as true statements those previously heard (even if they cannot consciously remember having heard them), regardless of the actual validity of the statement.
- inference-based bias: remember all the cheerleaders from high school as having blonde hair and the football players as being dumb jocks
- Reminiscence bump: the tendency to remember more events from adolescence and early adulthood than from other periods of our lives.
- Rose-tinted specs: the tendency to remember how wonderful things were in the past when it wasn’t.
- Stereotypical bias: memory distorted towards stereotypes, such as “black-sounding” names being misremembered as names of criminals.
- Telescoping effect: the tendency to displace recent events backward in time and remote events forward in time, so that recent events appear more remote, and remote events, more recent.
- Zeigarnik effect: the tendency to remember uncompleted or interrupted tasks better than completed ones.
Persistence: unwanted memory
While the persistence of memory can be vital to our survival, at the same time it can leave us haunted by past events we might rather forget. Living in a comfortable modern society may mean a person has relatively few real life-threatening dangers to face on a regular basis. But when people are exposed to more precarious environments, making the same mistake twice can be disastrous. But images and recollections of a traumatic event can become an intrusive and sometimes unbearable part of everyday experience. The most common example of this is Post-traumatic Stress Disorder (PTSD). Audie Murphy, the most decorated American soldier in history at the time of World War II, suffered from PTSD as a result of his experiences. According to his first wife, he suffered terrible nightmares and always slept with a gun under his pillow. Another example is the case of Donnie Moore of the California Angels, who threw the pitch that lost his team the 1986 American League Championship against the Boston Red Sox. Moore fixated on the bad play and eventually committed suicide.
The persistence of disturbing past episodes may also be important in depression, producing a dangerous cycle which may be key to the maintenance of depressive disorders. Ruminating over past events can lead to depression, while depression leading back in to rumination.
The most common form of treatment for negative persistence is called called critical incident stress debriefing, or CISD. Critical incident stress debriefing (CISD) has been used since 1983 as a component of Critical Incident Stress Management. The processes are intended to help individuals manage their normal stress reactions to abnormal events. The idea is that people who survive a painful event should express their feelings soon after so the memory isn’t “sealed over” and repressed, which could lead to post-traumatic stress disorder. Although used extensively, research findings to date yield mixed results. In a study in 2008, a group randomized trial of critical incident stress debriefing (CISD) with platoons of 952 peacekeepers, CISD was compared with a stress management class (SMC) and survey-only (SO) condition. The study found that CISD did not differentially hasten recovery compared to the other two conditions. For soldiers reporting the highest degree of exposure to mission stressors, CISD was minimally associated with lower reports of posttraumatic stress and aggression (vs. SMC), higher perceived organizational support (vs. SO), and more alcohol problems than SMC and SO.
An alternative to therapy is the use of drugs to help remove persistent memories. In 2008, Alain Brunet, a clinical psychologist at McGill University, identified 19 patients who had been suffering for several years from serious stress and anxiety disorders such as PTSD due to traumas including sexual assaults, car crashes, and violent muggings. People in the treatment group were given the drug propranolol, a beta-blocker used for conditions like high blood pressure and performance anxiety that inhibits norepinephrine, a neurotransmitter involved in the production of strong emotions. Brunet asked subjects to write a detailed description of their traumatic experiences and then gave them a dose of propranolol. While the subjects were remembering the event, the drug suppressed the visceral aspects of their fear response, ensuring that the negative feeling was somewhat contained. One week later, the patients returned to the lab and were exposed once again to a description of the traumatic event. Subjects who got the placebo demonstrated levels of arousal consistent with PTSD (for example, their heart rate spiked suddenly), but those given propranolol showed significantly lower stress responses.
As I noted, human memory has served as plot fodder for science fiction for years, but there’s room for many more stories to come. Maybe one will be yours.
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