It's on the Tip of Your Tongue
Tuesday, March 11, 2008
If only there were simple means to solve every tip of the tongue experience. You know the kind. Like the one I had a couple of months ago when I could visualize the Vermont clothing store where my friend Dan and I regularly stock up on white wool socks, but I just could not recall its name. Not until several weeks later, when I retrieved the plastic bag containing my last two pairs of slightly imperfect Wigwams, did I find the answer staring me in the face: Sam's.
Two questions flow from this experience: What made such a simple memory task so out of reach? Is this a bad sign?
We'll start with the less encouraging news.
First off, my brain is shrinking. (In case you are starting to feel smug, don't. Yours is, too.) Second, my subjective sense that it is not as easy as it once was to recall words is no illusion. Tip of the tongue experiences (TOTs) increase as we get older, and this is true in spades for the recall of proper names.
Here's some good news. While TOTs are a sign of aging (and have been shown to correlate with specific brain changes), they are not a sign of impending dementia.
Meredith Shafto, a research associate at Britain's University of Cambridge, has been studying normal cognitive aging for five years. TOTs, she says, are "part of what we call normal or healthy aging. . . . With normal aging there are changes that are noticeable and distressing and irritating, but they are not pathological."
What makes TOTs interesting is not that they are that dreaded knock on the door, but that they tell us something about how our brain functions normally to produce the vocabulary we use on a daily basis.
Deborah Burke, a psychology professor at Pomona College in Claremont, Calif., who has written widely about language, aging and TOTs, explains the current thinking:
"We like to think of words as being stored in a unit in our head, and that we have a little place in our minds where we have [for example] Brad Pitt, and we know what he looks like and what movies he's been in and his name and all that."
Instead of storing information that way, she explains, there is "a network of information across different parts of the brain, and you can lose access to one part and not the other. So you can see Brad Pitt's face and say, 'Yes, that's his face,' but you're not able to recall his name because it's not stored as a unit with his face or with [other] information about him."
As we age, the connections in our information network deteriorate, causing so-called transmission deficits. This is especially true when we haven't activated a particular connection for some time. What used to be a two-way street between Brad Pitt's face and his name is now, say, a bike path that has some overgrowth. The connection is still there, but it is weak and needs attention.
A recent study in the Journal of Cognitive Neuroscience reports a correlation between face-naming difficulties and shrinkage of a particular area of the brain. Shafto and colleagues showed a series of famous faces to adults between ages 19 and 88. Using MRI imaging, they found that increased TOTs were strongly associated with age-related atrophy in the left insular cortex, a cortical structure deep on the brain's left side.
This finding helps explain why we have more TOTs as we get older, but not why forgetting proper names is the most common problem. To understand this, we have to turn to transmission deficit theory, which provides a straightforward rationale.
Unlike most other words, proper names are arbitrary and usually tell us nothing about the person named. Larry King the name tells us nothing about Larry King the face or Larry King the man. If we lose the connection between the face and the name, we have no alternative route to get there. We may remember that his name starts with an L or has three syllables, but we still cannot quite make it all the way down the overgrown bike path to retrieve all the key word sounds (or phonology), which is what makes TOTs so frustrating. On the other hand, if we recall King's face and want to connect it to what he does (rather than what he calls himself), we have a lot of connections to choose from: talk show host, interviewer, emcee and so on.
One instructive exception to the proper name rule provides additional support for transmission deficit theory. Some cartoon characters have names that do in fact carry meaning (Spider-Man, Goofy), while some don't (Homer Simpson, Garfield).
In a recent article, "Charlie Brown Versus Snow White," in the Journal of Gerontology: Psychological Sciences, University of Colorado researchers tested young and old adults on how well they could name both kinds of characters. Young adults outperformed older adults on the naming test even though, as is routinely found in almost all studies on aging, the older adults did better on a standard vocabulary test. They just had trouble naming faces.
More pointedly, young adults differed little in their ability to name the two kinds of characters. Older adults, by contrast, had much more difficulty naming characters such as Charlie Brown and Garfield than they did Snow White and the Pink Panther -- names with an added semantic boost.
When I asked Burke what we can do to limit our TOTs, she enthusiastically endorsed the idea of using our language skills as much as possible in lively conversations where we are fully engaged and firing on all eight cylinders. Beyond that, she said, there are no all-purpose exercises to ramp up our ability to recall names from the past. Tried-and-true techniques do exist, however, to learn specific names at a specific time and place. We just have to apply these techniques every time we want to learn new names.
Still, I could not resist asking Burke if she thought doing crossword puzzles might have TOT-reducing benefits. She demurred, thinking I meant those rarefied crosswords with esoteric clues and solutions. I did not. I was referring to my mother-in-law.
Antoinette Berardi owned a truckload of moderately challenging crossword magazines with clues such as: Moby Dick author; Mo of Arizona; Mikhail's wife. I have clear recollections of her hunkering down at her kitchen table, turning to a fresh puzzle and blasting through that baby with the intensity of a NASA engineer working to rescue a crew from space. My wife claims that her mother did this to relax. I don't know about that, but I do know this: I have never met anyone with a more impressive memory. And, unlike her son-in-law, she never had to rehearse the name of the place she bought her socks.
Charles Zanor is a practicing psychologist in Massachusetts. Comments:firstname.lastname@example.org.