Forgetting occurs when people are unable to recall or access information that is stored in their long-term memories. Several different types of memory problems or lapses can happen to everyone, regardless of age, and can impact the way memories are retrieved, said Daniel L. Schacter, Ph.D., a professor of psychology at Harvard University.
The “seven sins of memory” were discussed by Dr. Schacter in a 1999 article published in the American Psychologist:
Transience: forgetting information or facts because they gradually fade or become less accessible over time.
Absentmindedness: forgetting certain details (e.g., to take medication or where one put one’s pen) when the person is not paying close enough attention.
Blocking: temporary inability to recall a piece of information at will.
Misattribution: partially remembering something accurately, but some details (e.g., time, place or person) are remembered inaccurately (e.g., eyewitness believes he or she saw someone rob the bank, when he or she actually saw the person somewhere else, but this can lead to the arrest and conviction even if the person didn’t commit the crime).
Suggestibility: false memories triggered by someone or something suggesting key information at the same time a person is retrieving a memory, which tricks the brain into thinking it’s a real memory (e.g., when children are questioned by police during cases of sexual abuse, they end up remembering they were sexually assaulted even when they weren’t).
Bias: the way that memories are organized and retrieved, as well as a person’s recollection of experiences influenced by personal biases (e.g., prior knowledge, experiences, beliefs, current mood).
Persistence: unwanted memories or recollections that the person is unable to forget.
Transience can actually be helpful for clearing out old memories or irrelevant information, facts, events and details that have occurred throughout one’s life, similar to cleaning out the temporary files in the hard drive of a computer, which can make it easier for people to recall and learn new information, said Dr. Schacter. In fact, forgetting old or unnecessary information is considered to be beneficial for optimal memory function, as well as for the ability to learn new things and remember new details about people, events and facts that have significance throughout life.
While forgetting a computer password or losing the car keys can be frustrating, sometimes forgetting isn’t always a bad thing — persistence, or the inability to forget unwanted, intrusive memories, is one such case. Rumination over past events in people with depressive disorders and the night terrors and flashbacks in individuals with post-traumatic stress disorder (PTSD) after they experience or witness a traumatic or disturbing event, can be extremely distressing. The difficulty these individuals have forgetting these traumatic memories can sometimes be more disabling than forgetting itself, said Dr. Schacter.
During memory experiments, researchers often ask people to remember a list of items under certain conditions to see how well they are able to retrieve the information. Directed forgetting experiments involve telling individuals to remember or forget some type of information that is presented to them during an experimental procedure. Aside from the items to be remembered during these experiments, the context (e.g., sights, sounds, smells) of an experimental procedure can change the way that a person’s memories are stored, organized and retrieved from his or her memory.
How to intentionally forget
A new study conducted by Jeremy R. Manning, Ph.D., an assistant professor at Dartmouth College, and his colleagues, suggested that people can intentionally forget by changing the context of their memories. Ten males and 15 females between the ages of 19 and 34 participated in eight study-test blocks, during which they were asked to study a 16-word list (list A). They passively viewed images of outdoor scenes in between each of the words and then were presented with an instruction to either “forget” or “remember” the list of items.
The participants then studied a second 16-word list (list B) without the scene images between the presented words, followed by an on-screen cue instructing them to verbally recall either the words from list A or B, and were given one minute to recall as many words as they could remember from the correct list. During the experiment, functional magnetic resonance imaging (fMRI) was used to track how long the participants were thinking about the scene or context representations that were presented to them.
The fMRI showed a substantial decrease in scene-related activity that occurred right after the participants were told to “forget,” which did not occur when the participants were told to “remember.” In addition, the amount of decrease in scene-related activity predicted how many of the words they could later remember.
These findings suggested that participants could directly suppress their thoughts by trying to think about new, unrelated thoughts to push out old contextual information. Intentionally thinking about irrelevant information to flush out the scene-related activity from their brains could be useful for helping them forget. This study has important implications for helping such people as those with PTSD, who have witnessed or experienced a traumatic event, overcome unwanted and intrusive memories.
Amanda Habermann is a writer for the Sovereign Health Group. A graduate of California Lutheran University, she received her M.S. in clinical psychology with an emphasis in psychiatric rehabilitation. She brings to the team her background in research, testing and assessment, diagnosis and recovery techniques. For more information and other inquiries about this article, contact the author at firstname.lastname@example.org.