After driving into the parking lot of my fitness center the other morning, I paused before getting out of the car to listen to a song on KABF. The lyrics, accompanied by an intriguing guitar riff, concerned quitting a job in Birmingham, Ala., loading up some stuff and a dog in a pickup, and going on an endless vacation. It echoed in my head while I changed into a swimsuit and dunked myself in a lap pool for an hour's swim.
I fully intended to ask my husband, who has an impressive ability to recall music and musicians, if he'd ever heard it when I got home. No need, though. By that time, the song had completely exited my memory--except for Birmingham and the dog. No melody, no chorus, no instrumentation remained.
Where did the song go? Why couldn't I remember it after a mere couple of hours?
It's understandable why people afflicted with dementia, Alzheimer's, cognitive impairment, concussion, multiple sclerosis, and brain injuries might have memory difficulties. But why do so many of us--regardless of age--have trouble recalling a neighbor's name, a previously familiar address, directions to a restaurant, and other information that should be readily accessible?
Even more exasperating are mind pops, those unexpected moments when a word or name or song or performer or whatever that you've been searching for in your brain suddenly shows up (journalists are well known for recalling dates, times, names, etc., about 20 minutes after an initial attempt to remember them).
And we're not even talking about when you leave the dustpan in the bathroom (where it doesn't belong) when sweeping the floors in your house, or the location of your fuzzy gloves that you had in hand a few minutes earlier, or picking up your credit card after using it at the grocery store's self-checkout, or which obscure furniture surface might contain your car keys left there when you entered the house 10 minutes ago.
Go ahead and despair, but don't obsess about it. People forget surprisingly fast, according to Verywell Mind (verywellmind.com), a resource for information on mental health topics. Approximately 56 percent of information is forgotten within an hour, 66 percent after a day, and 75 percent after six days.
That sounds about right, doesn't it?
Forgetting, the website explains, is the loss or change in information that was previously stored in short-term or long-term memory. It can occur suddenly or gradually.
In addressing my concern, the site asks, "Have you ever felt like a piece of information has just vanished from your memory? Or maybe you know that it's there, but you just can't seem to find it. The inability to retrieve a memory is one of the most common causes of forgetting."
Why are we often unable to retrieve information from memory? One possible explanation is decay theory: A memory trace is created every time a new memory is formed. Decay theory suggests that over time, these memory traces begin to fade. If the information is not retrieved and rehearsed, it will eventually be lost.
"One problem with this theory, however, is that research has demonstrated that even memories which have not been rehearsed or remembered are remarkably stable in long-term memory." That explains knowing all those song lyrics from the 1970s.
Research also suggests the brain actively prunes unused memories, a process known as "active forgetting." As memories accumulate, those that are not retrieved eventually become lost.
Really? Within a couple of hours? Maybe it's just me, but those memories are still there, somewhere. I just can't find them, until I experience a mind pop, and there they are.
I have a theory (based on zero scientific evidence) that the older we get, the more memories we accumulate, which eventually crowd out those that don't have much relevance. Despite my lack of empirical evidence, it turns out that there's a phenomenon known as interference: Some memories compete and interfere with other memories.
• Proactive interference is when an old memory makes it more difficult or impossible to remember a new memory.
• Retroactive interference occurs when new information interferes with your ability to remember previously learned information.
Other theories offer that retrieving some information from memory can lead to retrieval-induced forgetting, losing information has less to do with forgetting and more to do with the fact that it never made it into long-term memory in the first place, and that while you might remember the overall gist of something, you are likely to forget many of the details.
Thankfully, outside of finding them irritating, there's no need to worry about these lapses; they're normal.
What's not normal: Frequently pausing to retrieve words or memories. Forgetting recent events. Friends and family noticing memory loss before you do. Difficulty performing routine tasks, like paying bills and dressing. Getting lost in familiar places. Repeating the same conversation, over and over.
As an authorative talker (I can't remember who) said recently on NPR: Don't worry if you can't remember where you parked your car at Walmart. That's normal. Worry if you're standing in front of your car but don't recognize it as being yours.
Using that metric, so far, so good.
Karen Martin is senior editor of Perspective.