Scientists have proposed a new theory that ‘forgetting’ may be a vital part of learning and acquiring new knowledge.
Dr Tomás Ryan and Dr Paul Frankland, leading professors at Trinity College Dublin and the University of Toronto respectively, proposed the new theory in the international journal Nature Reviews Neuroscience.
The theory suggests forgetting may be a functional feature of the brain and that it could be a beneficial process which fosters more flexible behaviour and better decision-making.
Memories are stored in groups of neurons (nerve cells) called engram cells. To successfully recall these memories, the theory proposes that these cells need to be reactivated.
Forgetting subsequently takes place when engram cells cannot be reactivated. The memories are still there but they will not be recalled unless the engram cells are reactivated.
The theory proposes that memories gained in situations which are not entirely relevant to a person’s current environment may be forgotten.
Therefore, we may learn to forget certain memories over time and yet retain the memories that are important to us.
Dr Ryan said: “Our new theory proposes that forgetting is due to circuit remodelling that switches engram cells from an accessible to 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.”
The theory suggests that this process of forgetting certain memories could be a positive change that ultimately enhances our well-being as we learn to forget memories that become less relevant to us in our current environment.
For Dr Ryan and Dr Frankland, this new theory may also have implications with regards to forgetting in disease.
They noted: “Importantly, we believe that this ‘natural forgetting’ is reversible in certain circumstances, and that in disease states – such as people living with Alzheimer’s disease for example – these natural forgetting mechanisms are hijacked which results in greatly reduced engram cell accessibility and pathological memory loss.”
