Forgetting

Memory storage allows us to hold onto information for a very long duration of time—even a lifetime; however, there are many ways in which memory might fail to be retrieved, or be forgotten.

It is easier to remember recent events than those further in the past, and the more we repeat or use information, the more likely it is to enter into long-term memory. However, without use, or with the addition of new memories, old memories can decay. Transience refers to the general deterioration of a specific memory over time. This is particularly evident in short-term memory as short term memory begins to decline in old age leading to difficulties in free recall and also recognition. This is the opposite to mechanical memories such as a skill which is less likely to be forgotten, unlike information.

Memory can also be lost due to physiological diseases that interfere with the memory storage system in the body. Dementia is a disorder which causes injury to the brain and can lead to a decrease in mental processes. Alzheimer’s disease is commonly associated with those over the age of 65 and is a deterioration in the memory capacity of an individual in forgetting recent events. Korsakoff’s syndrome is a chronic memory disorder that is caused by alcohol abuse and causes memory loss due to a lack of vitamin B1.

Aside from biological ageing and disease, several theories address why we forget memories and information over time, including trace decay theory and interference theory.

The trace decay theory of forgetting states that all memories fade automatically as a function of time. Under this theory, you need to follow a certain pathway, or trace, to recall a memory. If this pathway goes unused for some amount of time, the memory decays, which leads to difficulty recalling, or the inability to recall, the memory. Rehearsal, or mentally going over a memory, can slow this process. But disuse of a trace will lead to memory decay, which will ultimately cause retrieval failure. This process begins almost immediately if the information is not used: for example, sometimes we forget a person’s name even though we have just met them.

MCAT Forgetting

Memory interference: Both old and new memories can impact how well we can recall a memory. This is known as proactive and retroactive interference.Proactive interference occurs when old memories hinder the ability to make new memories. In this type of interference, old information inhibits the ability to remember new information, such as when outdated scientific facts interfere with the ability to remember updated facts.

Retroactive interference occurs when old memories are changed by new ones, sometimes so much that the original memory is forgotten. This is when newly learned information interferes with and impedes the recall of previously learned information.

MCAT Forgetting

Trace decay, interference, and lack of cues are not the only ways that memories can fail to be retrieved. Memory’s complex interactions with sensation, perception, and attention sometimes render certain memories irretrievable.

If you’ve ever put down your keys when you entered your house and then couldn’t find them later, you have experienced absentmindedness. Attention and memory are closely related, and absentmindedness involves problems at the point where attention and memory interface. Common errors of this type include misplacing objects or forgetting appointments. Absentmindedness occurs because, at the time of encoding, sufficient attention was not paid to what would later need to be recalled.

Occasionally, a person will experience a specific type of retrieval failure called blocking. Blocking is when the brain tries to retrieve or encode information, but another memory interferes with it. Blocking is a primary cause of the tip-of-the-tongue phenomenon. This is the failure to retrieve a word from memory, combined with partial recall and the feeling that retrieval is imminent. People who experience this can often recall one or more features of the target word, such as the first letter, words that sound similar, or words that have a similar meaning. Sometimes a hint can help them remember: another example of cued memory.

Memory retrieval can also be inaccurate and often leads to false memory. This occurs when people remember events differently from the way they happened or, in the most dramatic case, remember events that never happened at all. False memories can be very vivid and held with high confidence, and it can be difficult to convince someone that the memory in question is wrong. They have not forgotten the event but have constructed events that either never happened or happened in a different order.

Practice Questions

Khan Academy

MCAT Official Prep (AAMC)

Section Bank P/S Section Question 17

Section Bank P/S Section Question 32

Section Bank P/S Section Passage 5 Question 36

Sample Test P/S Section Passage 1 Question 5

Practice Exam 2 P/S Section Question 44

Practice Exam 3 P/S Section Passage 2 Question 7

Practice Exam 4 P/S Section Passage 9 Question 48

Key Points

• Memories are affected by how a person internalizes events through perceptions, interpretations, and emotions.

• Transience refers to the general deterioration of a specific memory over time.

• Ageing and disease can lead to the loss of memories and difficulties of retrieval.

• The trace decay theory of forgetting states that all memories fade automatically as a function of time; under this theory, you need to follow a certain path, or trace, to recall a memory.

• Under interference theory, all memories interfere with the ability to recall other memories.

• Proactive interference occurs when memories from someone’s past influence new memories; retroactive interference occurs when new ones change old memories, sometimes so much that the original memory is forgotten.

• False memory is a phenomenon where a person recalls something that did not happen or recalls it differently from the way it actually happened

Key Terms

Transience: the deterioration of a specific memory over time

Trace decay theory: the theory that if memories are not reviewed or recalled consistently, they will begin to decay and will ultimately be forgotten

Retroactive interference: when newly learned information interferes with and impedes the recall of previously learned information

Proactive interference: when past memories inhibit an individual’s full potential to retain new memories.

Trace: a pathway to recall a memory

Absentmindedness: a state of forgetfulness of simple memories and retrieval

Blocking: when the brain tries to retrieve or encode information, but another memory interferes with it

Interference theory: other memories interfere with the ability to recall memories

False memory: a phenomenon where a person recalls something that did not happen or recalls it differently from the way it actually happened

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