Everyone knows that as we get older our memories start to fail. That’s why those little slips of forgetfulness—What was that neighbor’s name? Where did I leave my cell phone?—are often called “senior moments.” Yet the stereotype of the faulty aging brain may turn out to be partly a self-fulfilling prophecy.
In a new study by Ayanna Thomas, an assistant professor of psychology in the School of Arts and Sciences, older adults who were told that memory tends to decline with age did worse on a word-recognition test than older adults who didn’t get the dispiriting prompt.
For the experiment, which Thomas conducted with former doctoral student Stacey J. Dubois, G11, both older adults (ages 60 to 74) and younger adults (ages 18 to 22) were given lists of words to study. After a brief delay, they were given a recognition test, where they were presented with words and asked whether each word had appeared before.
On the test, the researchers intentionally put in several words that were semantically related to the studied words, but never presented. For example, participants may have seen words associated with “window,” such as “sill,” “sash” and “glass,” but not the word “window” itself. As expected, the older adults did worse on the recognition test than the younger adults, and both groups fell for some of the lures—recognizing “windows” that weren’t there.
The researchers found, however, that they could influence how often the older adults were taken in by the lures. After all the participants studied their lists, half of them were read a paragraph about age-related declines in memory and were specifically told they would be taking a memory test. The others were told that they would be given an assessment that examined verbal ability, and that older adults often do better on these assessments because they have more experience with vocabulary.
Listening to the statements seemed to have no effect on recognition performance in the younger adults. But the older adults who were reminded that memory declines with age were much more likely—20 percent more—to fall for the lures than those who heard the verbal ability statement. That group—the ones who thought it was their language acumen on trial—actually did just as well as the younger participants in avoiding the lures.
Experiments like these examine what is known as “stereotype threat.” Researchers have found similar results with African-Americans taking intelligence tests and women taking math tests. For example, when women are told before an exam that men are better at math, or if they are simply read something that reminds them of their gender, they get lower scores than women who don’t hear those statements.
Thomas hypothesizes that when people think they are in a situation that could reinforce a stereotype, it is a drain on their brain power. “They are anxious, and they are spending cognitive resources thinking about their anxiety, trying to mediate their anxiety and not spending enough of those resources on the task at hand,” says Thomas, director of Tufts’ Cognitive Aging and Memory Lab. “If you can’t devote your full attention to the test, you are not going to perform as well.”
Planting the semantically related “lures” in this experiment was not just the researchers being tricky: It helped them pay particular attention to false memories, which previous experiments have shown seniors are more susceptible to than younger people. One theory is that in forming memories, older people rely more on the relationship that things (in this case, words) have to one another than on what differentiates them (the order they appear in, for example, or what each word brings to mind when it is read).
Experiments such as this one, Thomas says, are asking, “How can we get people to be as accurate as they possibly can? How can we get people to avoid being susceptible to distorting or misleading information?”
Preventing false memories can have important practical applications, Thomas says. While forgetting what sweater you wore yesterday may have few consequences, misremembering information on the witness stand in a court of law can have dire consequences.
“Memory accuracy is particularly important when there is a high cost associated with memory errors,” she says.
Julie Flaherty can be reached at email@example.com.