TYPES OF MEMORY FAILURE

From the book «The Seven Sins of Memory: How the Mind Forgets and Remembers» written by Daniel Schacter, former chair of Harvard University‘s Psychology Department and a leading memory researcher.

Transience

Transience refers to the general deterioration of a specific memory over time. Much more can be remembered of recent events than those further in one’s past. This is especially true with episodic memory, because every time an episodic memory is recalled, it is re-encoded within the hippocampus, altering the memory each time you recall it. Transience is caused because of interference. There are two types of interference: proactive interference (old information inhibits the ability to remember new information), and retroactive interference (new information inhibits the ability to remember old information).

Absent-mindedness

This form of memory breakdown involves problems at the point where attention and memory interface. Common errors of this type include misplacing keys, eyeglasses, or forgetting appointments because at the time of encoding sufficient attention was not paid on what would later need to be recalled.

Blocking

Blocking is when the brain tries to retrieve or encode information, but another memory interferes with it. Blocking is a primary cause of Tip of the tongue phenomenon (a temporary inaccessibility of stored information).

Misattribution

Misattribution is the first of the sins of commission which are discussed in the book. It entails correct recollection of information with incorrect recollection of the source of that information. For example, a person who witnesses a murder after watching a television program may incorrectly blame the murder on someone she saw on the television program. This error has profound consequences in legal systems because of its unacknowledged prevalence and the confidence which is often placed in the person’s ability to know the source of information important to suspect identification.

Suggestibility

Suggestibility is somewhat similar to misattribution, but with overt suggestion. It is accepting false suggestion made by others. Memories of the past are often influenced by the manner in which they are recalled, and when subtle emphasis is placed on certain aspects which might seem likely to a specific type of memory those emphasized aspects are sometimes incorporated into the recollection, whether or not they actually occurred. For example, a person sees a crime being committed by a redheaded man. After reading in the newspaper that the crime was committed by a brown-haired man, the witness «remembers» a brown-haired man instead of a redheaded man.

Loftus and Palmer’s work into leading questions is an example of such suggestibility.

Bias

The sin of bias is similar to the sin of suggestibility in that one’s current feelings and worldview distort remembrance of past events. This can pertain to specific incidences and the general conception one has of a certain period in one’s life. This occurs partly because memories encoded while a person was feeling a certain level of arousal and a certain type of emotion come to mind more quickly when a person is in a similar mood. Thus, a contented adult might look back with fondness on their childhood, induced to do so by positive memories from that time which might not actually be representative of their average mood during their childhood.

Persistence

This failure of the memory system involves the unwanted recall of information that is disturbing. The remembrance can range from a blunder on the job to a truly traumatic experience, and the persistent recall can lead to formation of phobias, post-traumatic stress disorder, and even suicide in especially disturbing and intrusive instances.