Of all the common afflictions from which humankind suffers, forgetting is probably the most common.
— and co-authors, Forgetting
To learn effectively, we must find a way to retain new information in memory. For the vast majority of people, forgetting is a frequent experience despite our determination to learn.
It can come as a surprise that some people question whether forgetting exists at all:
It has not yet been proved that there is any such thing as forgetting; all we know is that the act of recollection does not lie within our power.
— , Morgenröte (The Dawn of the Day)
With that in mind, it becomes necessary to define what is meant by forgetting:
- Strong forgetting: Total erasure of the original memory and a complete inability to recall
- Weak forgetting: Forgetting due to a failure to retrieve or inability to access a memory.
Although it is possible that strong forgetting exists, there is no available evidence to prove it. Forming a memory leads to molecular changes in the brain, so strong forgetting would involve completely reversing those changes. The brain works differently than electronic memory. It does not save exact copies of experiences. Instead, the brain integrates information into a network of existing knowledge and continues to modify memories well after the experience took place. Different theories exist for how forgetting occurs. The simplest, but least useful, is that memory decays over time, like a muscle that atrophies if not used. Another theory is that forgetting occurs due to interference either from prior knowledge or new information.
A well-supported theory of forgetting differentiates between storage and retrieval of memories. Unlike the storage in electronic devices, human memory appears to have virtually unlimited capacity. But our ability to recall information is often unreliable, as anyone who has suddenly found themselves unable to remember a password or security code can attest.
Retrieval strength is the bottleneck, and it declines with disuse. Memories that are not frequently accessed become less accessible. The act of retrieving a memory makes it easier to recall later.
Forgetting plays a vital role in human cognition. People are exposed to an abundance of information and stimuli. The ability to filter out what is important from the noise is essential. People with rare conditions that interfere with forgetting — like synesthesia or hyperthymestic syndrome — can become distracted and overwhelmed by their vivid memories.
In the practical use of our intellect, forgetting is as important a function as recollecting.
— , The Principles of Psychology
Despite its beneficial functions, in the context of learning, individuals must interrupt the process of forgetting. To learn effectively, we need to understand the factors that influence retrieval.