"It's on the tip of my tongue." We all say it when that word or a name doesn't immediately come to mind.
The tip-of-the-tongue phenomenon is a common example of "blocking," which is the temporary inability to retrieve a memory. In many cases, the barrier is another memory similar to the one you want, and oftentimes you retrieve the wrong one. This competing memory is so intrusive that it prevents you from thinking of the right memory.
Scientists believe that memory blocks become more common and more frequent as we age, and that they account for older adults having difficulty remembering other people’s names. Research has shown that people are able to retrieve about half of the blocked memories within a minute.
Blocking doesn’t occur because of lack of attention or because the memory has faded; it happens because something is keeping you from retrieving it.
Elizabeth Loftus, a contemporary psychologist and acclaimed researcher in memory, suggests that there are four explanations for forgetting: retrieval failure, interference, failure to store and motivated forgetting.
A possible reason for retrieval failure, as in trying to remember a person’s name, is known as decay theory. Loftus explains that, according to this theory, a memory trace is created every time new information is taken in. Over time, these memory traces begin to fade and disappear or decay. So, if the information is not retrieved and rehearsed, it will eventually be dropped from the person’s memory. One flaw in this theory that Loftus notes is that research has demonstrated that even memories which have not been rehearsed or remembered are remarkably stable in long-term memory.
Proactive and retroactive interferences are barriers in our memories. They create the competing intrusive memories. A proactive interference is when an old memory makes it more difficult or impossible to remember a new one. A retroactive interference occurs when new information hinders your ability to remember previously learned information. Loftus suggests that rehearsing new information is the most effective approach as it is less likely that old information will compete with the new.
Sometimes blocking memory is just a failure of the brain to store the information. That has less to do with forgetting and more to do with the fact that the memory never made in into our long-term memory base in the first place. The encoding simply failed and prevented the information from being stored.
Motivated forgetting is when we actively try to forget, especially memories of traumatic or disturbing events or experiences. This type of forgetting is also described as persistent memory and is the seventh and last of the normal age-related memory problems illustrated by Harvard Health Publishing and based on "The Seven Sins of Memory: How the Mind Forgets and Remembers," by Daniel Schacter.