We all would like to improve our memories. Although some high-profile cases of faulty memory (like that of Brian Williams) have recently made the news, everyone suffers from memory lapses. For some, those memory lapses can be annoying and upsetting. Forgetting to take something with you when you leave home means that you can arrive at work without your keys, a friend’s house without your phone, or the store without your wallet. Accidentally misplacing those keys, phone, or wallet can cost you not only lost time, but emotional agony until the lost item is found.
Psychology tells us that the best way to keep memories alive is to rehearse them over and over again. Running through a shopping list several times will allow you, so the thinking goes, to engrave it in your brain so that—should you leave the list at home—you’ll still arrive home with all the eggs, flour, and veggies you intended to buy.
Getting cute with your memory is another suggested trick. Want to remember the name of someone you meet for the first time? Improving your social memory may just be a matter of finding weird associations between the name (“Frank”) and something about the person’s face (“freckled”).
Many of these tried-and-true memory tricks can prove helpful. However, new research shows that the more effort you put into remembering some things, the more likely it is that you’ll forget others. University Hospital of Magdeburg, Germany’s Maria Wimber (2015) and co-authors were interested in discovering the brain’s activity a specific type of memory task involving two competing memories. As they point out, “Remembering …is a double-edged sword….The remembering process…induces forgetting of other memories that hinder the retrieval of the memory that we seek.”
The “dark side” of remembering might occur when you try to recall one of two competing facts in memory. Bringing to mind one, according to Wimber’s response competition theory, leads the other one to fade away. For example, you may meet two men at a party, both of whom have freckles (let’s say one of them is the aforementioned Frank). Now let’s say you see freckled guy “A” (Frank) in the elevator. You stop for a second, think “OK, it’s a freckled guy—is it Frank or Fred?” Once you realize it’s Frank, according to response competition theory, you’re now going to be less able to remember the name of freckled guy “B” (Fred).
The very act of remembering that it’s Frank and not Fred, according to Wimber and her team, will cause the memory trace for Fred eventually to go underground and become unretrievable. As their experiments found, the neural basis for that “Fred” memory will actually become inhibited, or suppressed.
In the experiments Wimber and her team conducted, participants completed a two-phase experiment: In the first phase, participants were trained to remember one set of word—image pairs (such as Marilyn Monroe’s face, paired with the word “sand”). In the second phase, they were given a new set of images to associate with the same words. In the test phase, participants were instructed to indicate which category of image was associated with the word (in this case, face or object). Prior to this, the Wimber team identified the brain activation associated with both the target (Marilyn Monroe) and the competitor (hat). Over repeated trials, not only did brain activation for Marilyn’s face increase when they saw the word “sand,” but that associated with the hat decreased below the simple non-response baseline.
Our brains, then, seem to banish the information we no longer need in memory—not just forget it, but inhibit it altogether. Returning to our freckled friend experiment, it’s not just that your ability to call Frank by name increases, but your brain must put in the effort to tamp down your tendency to call him Fred. If not, you’ll continue to get them confused.
If in fact our brains help us shape our memory to be able to conjure up the information we need, rather than the information we don’t need, this can be highly adaptive. Useless knowledge needs to be driven out of our minds or it will keep interfering with what we need to know. Although this has been known for some time in interference theories of memory, the Wimber et al. experiment shows how the process seems to operate at the neural level.
Now you know how your brain tries to help you become more efficient at remembering what you need when one set of information can interfere with another. How can you turn this around to help you remember what you might, but don’t necessarily, need to remember? With the Frank/Fred example, if you think you might need to greet Fred on a future occasion, even though you don’t see him that often, you’ll need actively to pull that memory up once in a while. Consider another similar situation: You have two passwords for two different online accounts. One is for an account you hardly ever use, and one is for one you use every day. Your brain will expunge, and actively suppress, the competing password information. To counteract this, you’ll need to force yourself to remember the less-frequently-used one, even if you don’t think you’ll need it.
To keep knowledge alive, then, it’s not enough to tuck it away and hope for the best. You’ve got to revive it every so often or it will disappear forever. It’s because our memories are adaptive that they’re so fallible.
Instead of blaming poor memory each time you forget, this research shows that you can congratulate it for being so good.