Why do some experiences become memories, to be savored again and again, while others slip unnoticed into the dark recesses of our minds? It’s a question we don’t often consider as we go about our lives, and it isn’t until later, when we try to recall something, that we realize it might be completely gone.
We had this discussion last week, when my adult children came to Thanksgiving dinner, and the subject of childhood memories came up. As we compared notes, it was clear that each of us had a different ‘take’ on some events we all experienced.
In discussing my own childhood, I revealed that I remembered very little of my early years, and said how I regretted that. Sometimes, I told them, I would evoke a mere glimpse of a memory, of my siblings and my parents, and then try to remember some of the conversation, or something that might have happened. But I was never successful, I said, in getting any further.
When my siblings and I discuss past events, I told them, I’m always amazed at how our recollections differ, and how each person’s version emphasizes some things, and underplays others. I marvel at how selective those memories are, with different emotional overtones and interpretations layering what we recall.
This demonstrates to me, that memory is not a ‘thing’. Rather, it’s a term covering many types of recollections that are distinct, and unique to each person. The brain is complex, and no one really knows absolutely how memories are made. There are as many theories about this as there are scientists, but here is a short explanation:
Where do memories begin?
Experiences, like those discussed in our conversation last week, begin in our sensory system, the moment by moment events that happen. During this stage, information coming through our senses is stored for a very brief period of time, generally for no longer than a half-second for visual information and 3 or 4 seconds for auditory information. We grasp only parts of this sensory memory, allowing some of it to transfer to the next stage, short-term memory.
Sometimes called active memory, short-term memory refers to our recall of things that happened recently, the information we are currently aware of—what we are currently thinking about. It’s fleeting, lasting between 15 and 30 seconds. It holds the information we are currently working with and using for cognitive tasks. This memory, according to Freudian psychology, is the conscious mind.
Paying attention to it, anchoring it in some way, (even thinking, “I will remember this”) allows it to continue to the next stage, long-term memory.
This stage (the unconscious in Freudian psychology), refers to the continuing storage of information. This information is largely outside of our awareness but can be called into working memory to be used when needed, according to each person’s retrieval ability.
Researchers don’t all agree on the likelihood that the brain stores ALL of life’s experiences. Some scientists speculate that memories which are stored are in some way edited and sorted, and that some of the more peripheral details are never stored.
Here’s what I really want to know
But here is the real nub of my question:
Can the mind select the information, dig it out of the long-term memory bank, and refresh it anew, so that it can come forward as a memory? And is some of that old information completely gone?
It turns out that not all long-term memories are created equal. Neuroscientists claim that information that is of greater importance leads to a stronger recall. How the memory was encoded, the patterns of neuron activity in various parts of your brain at the time of the experience, can have a bearing on whether or not it will be easily remembered.
If you were very aware and alert, when you had the experience, for example, it will be more vivid, and more likely to be remembered. That is why important events such as your graduation ceremony or the birth of your children are more clearly remembered than other less significant experiences. So it makes sense that some memories will spring to mind quickly, while others are weaker and might require prompts or reminders to help you recall them.
There’s so much new research addressing serious issues such as helping Alzheimer’s patients, healing people with PTSD, and increasing student effectiveness. My question on lost memories seems frivolous by comparison.
What do researchers say?
But before I abandon it, here are some interesting studies.
Researchers in the lab of Susumu Tonegawa at the Picower Institute for Learning and Memory at MIT conducted a series of studies, concluding that those memories are still there, it’s a just a matter of finding the best way to retrieve them, which hasn’t been worked out yet.
Neuroscientist Dean Burnett says that recall of a memory is a mysterious process, in which “signals from our frontal cortex link to that memory via uncertain means, and the memory is reconstructed from the information available.” The memory hasn’t disappeared, she says, it’s just that you can’t find a way to retrieve it.
“It’s a bit like losing a glove – you still own a glove, it’s in your home somewhere, but you can’t use it.”
When writer Joe Fingas, discusses scientists using small jolts of electricity to revive recent memories (in a 2016 article in Engadget), he brings some humor to the issue.
“You can’t apply this method to long-term memories (you likely need different techniques for that), so don’t expect to revisit your childhood with a zap to your head. However, the findings should improve our understanding of how the brain works — it’s already clear that memory is more complex than we thought.”
And just like that, he (almost) answered my question.