Tip of the Tongue

by Dr. Bill Thomas

People of all ages are familiar with the experience of knowing a name, having that name right on the tip of the tongue, and— not being able to produce the name. The man who created the first English dictionary, Samuel Johnson was familiar with this circumstance and the meaning that society attached to it. In 1783 he wrote: ” There is a wicked inclination in most people to suppose an old man decayed in his intellects. If a young or middle-aged man, when leaving a company, does not remember where he laid his hat, it is nothing; but if the same inattention is discovered in an old man, people will shrug up their shoulders, and say, “His memory is going.”

As is so often the case with elderhood, the problem here lies mainly in the culture of ageism.  What Dr. Johnson didn’t know is that, someday, neuroscientists would provide a surprisingly common sense explanation for this common experience.  It turns out that younger brains are good at quickly recalling bits of information (like a name or where you put your car keys) because they have a relatively straightforward filing system. Older people, by dint of long experience, “store” memories within a more diffuse network of brain systems. The author of a 2011 study published in the journal “Brain Research” described the effect this way: “We’re all accessing the same brain networks to remember things, but we have to call in the troops to do the work when we get older, while we only have to call in a few soldiers when you’re younger.” This simple insight actually helps explain a few of the normal but puzzling mental phenomena associated with aging.

First, there is abundant evidence that mental agility declines with age. If that sentence makes you feel uneasy, recall that maximum sprinting speed also declines with time. Both of these things are true but there is no stigma attached to not being able to run the 100 meter dash in under 13 seconds. Almost twenty years ago, Betty Friedan, in her book “The Fountain of Age” did us all a favor when she drew attention to research that asked “Is there something more valuable than mere agility?”  Ohio State psychologist Roger Ratcliff and his colleagues have been conducting detailed studies of mental agility for more than a decade. Where most research of this kind focusses exclusively on mental speed, Ratcliff’s team looked at the relationship between speed and accuracy.

One of their studies looked at more than 300 subjects as they watched as a group of asterisks flash on a computer screen. The number of on-screen asterisks was either “small” ( between 31 to 50) or “large” (between 51 to 70). After seeing the image participants were asked to classify into one these two groups.  While increasing age was clearly associated with decreased speed, the accuracy of the older subjects matched that of younger people. When Ratcliff’s team actively encouraged the older participants to focus more on speed and not worry about accuracy, their reaction time matched that of the college students in the study.

Elders understand that defects in accuracy are more stigmatizing than slower reaction times. Accordingly, a rational older man has every reason to avoid having people say of him, as they did of the man who forgot his hat, “His memory is going.”  Ratcliffe explains, “Older people don’t want to make errors, so what they do is adopt a more conservative decision criteria and that slows them down.” Other studies have shown that, while younger people are better at finding patterns in strings of numbers, older people are better at identifying strings that have no pattern. This ability to not be drawn into finding patterns that don’t exist, the ability to reserve judgement, is the basis for some impressive new skills.

Age has been shown to increase our ability to extract the essential meaning of a story or event. Older people are better than young people when it comes to capturing the gist of things. How do they do this?  Experience helps. Having been in similar situations before is valuable but that is not all.  Because elder’s brains distribute memories more widely within the brain than they did in earlier decades, activating these memories draws on a wide array of brain system.  This more global activation assists them in “seeing the big picture” that younger people can so easily miss.

But that’s not all.

The changing distribution of memory, which helps elders get the gist of things can also make swiftly recalling a single word or idea more difficult. Hence, the “senior moment.” Neuroscientists  have done considerable work on this “tip-of-the-tongue” phenomenon.  Stated in objective terms, it is the failed attempt to retrieve a word, number or name from memory (partial recall sometimes produces a letter or syllable) combined with the feeling that recall is immanent. The resulting unpleasant sensation is thought to be due in part to the elder’s wider distribution of memory. Plucking a specific name out of a life time of memories really is more challenging for older people than younger people.  The elder’s attempt to do so requires them to activate a wide array of brain structures and this assists with inference. Sorting through clues found in different parts of the brain is effective, but it takes time.

This is where our ageist culture re-enters the picture. The emphasis on speed over accuracy leads many people people to hit the panic button and declare a “senior moment” when in fact they are experiencing a minor drawback from what is actually a major mental accomplishment.