Memory is in the center of attention these days. Especially since the number of people with dementia which causes memory to fail, is growing. Everybody would be afraid of losing one’s memory. But what about the hell people go through who can remember literally everything that went on in their lives. It turns out forgetting isn’t such a bad thing after all.
Forgetting is inextricably bound with remembering. We are supposed to forget the largest part of what enters our brains to keep them from overloading. It would be disastrous if everything we experience and learn ends up in our long-term memory. Total recall would paralyse us mentally.
Some examples are known of people who are able to remember everything they did in their lives since they were young, a disorder called hyperthymesia. This is a life-disrupting disorder since sufferers cannot control the constant stream of memories.
Forgetting is a perfectly normal, everyday experience and a positive one. Efficient memory means we forget much of what we experience, far more than we remember. Memory tends to be best for meaningful and important matters. For example, you normally don’t remember what you have eaten three days ago. These facts are so irrelevant they are not preserved. In fact, we quickly forget anything that is not supported by a motivation and does not lead to an action. Evolution shaped memory to mainly store information we might need.
Forgetting is the normal loss of or diminished access to information. It is an inability to retrieve memory from long-term storage. It can have three possible causes: storage loss, retrieval failure or encoding deficiency, which means insufficient information has been put into storage.
Within the study of psychology, four main theories of forgetting have taken root. The decay theory states that memory deteriorates and becomes more fragmented over time. In the end, a memory simple fades away if we don’t recall it anymore.
The defective recall theory presents forgetting as a disturbance in the retrieval of information not in its storage. Stimuli or cues that were present at the time the memory was formed, have not been stored, which makes it impossible to correctly recall the memory.
Another theory is called motivated forgetting. This concerns unconscious mechanisms that are at work to make us forget unpleasant or painful facts. Repression – unconsciously pushing unwanted memories out of awareness – is such a type of forgetting. The related suppression is a conscious effort to put something out of one’s mind.
The interference theory supposes that a piece of information is forgotten because some other piece of information prevents it from being retrieved. In proactive interference, prior information inhibits the ability to remember new information. In retroactive interference, new information inhibits the ability to remember old information.
Neurones and proteins
When memories are stored, physical changes take place in and among neurons. The same is the case for losing memories. Close-knit networks of neurones that frequently communicate with each other are being established to form a memory. The contacts one neurone makes with other neurones are not fixed. Forgetting has to do with contacts being broken. This may be caused by decay when stored information isn’t recalled anymore and the contacts between neurones become loose or disrupted.
Certain chemical substances within the brain may also be involved in the process of forgetting. Various proteins have been discovered so far that play a role in memory and in forgetting. Some are involved in memory formation. A lack of these proteins may result in memory deficits. An excess of other proteins may result in erasing memories. One protein has been found that is involved in actively removing memories to make room for new information.
Unfortunately, we are not able to consciously influence the process of forgetting. We would prefer to forget some annoying or painful memories that have been stored efficiently. But the more you are trying to forget them, the better they become engraved in long-term memory since you are activating the networks involved in the memory over and over again.
Often, time lends a helping hand because a network becomes less firm over time. Forming new memories is also very useful because then other, older memories will disappear into the background.
A specific case of not being able to forget is a post-traumatic stress disorder. This is a severe anxiety disorder that can develop after exposure to a very traumatic event. A person that has been in a life threatening situation can still suffer nightmares, increased arousal, and other mental problems many years later. The neuronal network that was created during the traumatic event is so stable that it is almost impossible to dissolve it. Many therapy sessions at a psychologist are necessary to make the fear and distress manageable.
What the psychologist is trying to do together with the patient is close off the extremely well-established contacts between neurones that automatically bring up the fearful images. Instead, the neurones involved have to make contact with other neighbours so that together they will conjure a more objective picture of the traumatic event.
This may be brought about by recounting the story over and over again and realising the experience admittedly was awful, but not the end of the world. During this learning process neurones involved establish new connections and bit by bit the old, undesired network becomes obsolete.
“We are people, not brains. We are that abstraction that occurs when a mind, which emerges from a brain, interacts with the brain.”
Michael Gazzanigga, neuroscientist
Of course it would be fantastic if you could erase just one, nasty memory by taking a pill. We still have some time to go before such a remedy will exist, but scientists have made good progress in understanding what happens in and between brain cells during the process of forgetting.
They have discovered a protein that is in particular involved in fearful memories. An overdose of this protein can erase these scary memories. In their laboratory, the researchers have succeeded in deleting just one specific scary memory in mice. People will have to wait a little longer before they can make use of this technique since it involves manipulation of genes and it is still unclear what would be the consequences of that.
Forget-me-not flowers © whiteaster – Fotolia.com
Cartoon © cartoonresource – Fotolia.com