Why do we forget? It could be that the memory has disappeared and is no longer available or perhaps it is still there but cannot be retrieved. There are a number of psychological theories relating to memory and why we forget. Here, we consider some of these theories and also some non-psychological thoughts on why we forget.
Sigmund Freud is known for his repression theory. He believed that repression occurs when a thought, memory, or feeling is too painful for an individual, so the person blocks this memory out of consciousness and is not aware of the existence. Mike Eysenck discusses this theory in his article “Why do we forget?” when he looks at how psychodynamic therapists might sometimes put pressure on people to “retrieve non existent memories.” He did conclude that repression “almost certainly exists” but that forgetting is not just due to repression and there are other reasons why we forget.
Interference theory was a dominant approach to forgetting throughout most of the twentieth century.
“Interference is an explanation for forgetting in long term memory, which states that forgetting occurs because memories interfere with and disrupt one another, in other words forgetting occurs because of interference from other memories” (Baddeley, 1999).
There are two ways in which interference can cause forgetting:
- Proactive interference occurs when you cannot learn a new task because of an old task that had been learnt. When what we already know interferes with what we are currently learning – where old memories disrupt new memories.
- Retroactive interference occurs when you forget a previously learnt task due to the learning of a new task. In other words, later learning interferes with earlier learning – where new memories disrupt old memories.
In 1960 Postman and Underwood conducted a research study to investigate if new learning interferes with previous learning. Participants were divided into two groups. Group A had to learn a list of word pairs i.e. dog-field, they were then asked to learn a second list of word pairs where the second paired word was different i.e. dog-cup. Group B were asked to learn the first list of word pairs only. Both groups were asked to remember the first list of word pairs. The results showed that Group B’s recall of the first list was more accurate than the recall of group A. This suggests that learning items in the second list interfered with participants’ ability to remember the list. This is an example of retroactive interference.
However, Eysenck states that “interference has been mainly demonstrated under artificial laboratory conditions and we do not have clear evidence concerning how much forgetting in everyday life depends on interference.”
Another approach is the encoding specificity principle. Endel Tulving believed that remembering is linked to similar information stored in the memory trace. He argued that our emotional state is important when thinking about memory. Eysenck references research conducted by Kenealy (1997) where people recalled more information when they were sad at both learning or retrieval than when their mood state switched between learning and retrieval.
However, Eysenck found gaps in this theory and states that it is “oversimplified” and proposes that we use more of a problem-solving approach by more of a process of elimination when remembering what we did on a certain day for example. What do I usually do? What else was I doing around that particular day? Etc.
From a scientific perspective there is recent research that suggests that forgetting is actually a form of learning. Neuroscience professor, Dr Tomás Ryan, states that:
“Forgetting is due to circuit remodelling that switches engram cells from an accessible to an inaccessible state. Because the rate of forgetting is impacted by environmental conditions, we propose that forgetting is actually a form of learning that alters memory accessibility in line with the environment and how predictable it is.” This idea contrasts to the psychological theories that have been put forward.
Another non-theory aspect of forgetting is impaired memory due to Alzheimer’s disease which “is a brain disorder that slowly destroys memory and thinking skills, and, eventually, the ability to carry out the simplest tasks.” Alzheimer’s disease is named after Dr. Alois Alzheimer. In 1906, Dr. Alzheimer noticed changes in the brain tissue of a woman who had died of an unusual mental illness and her symptoms included those typical of the disease nowadays.
