Let’s try something.

Take a moment and imagine yourself in old age. Not just a more wrinkled version of your face or more gray in your hair, but the bigger stuff, too: What do you do? How do you feel?

There’s no shortage of stereotypes to choose from: Are you in the prime of your life, the golden years, dispensing an endless stream of wisdom? Or are you cantankerous, forgetful, fearful of your own decline? In this imaginary scenario, are you spry or wizened? Are you beloved by your family, or are you their burden?

The answers to these hypothetical questions matter in very real ways.

Becca Levy, the director of social and behavioral sciences at the Yale School of Public Health, has spent much of her career examining how cultural perceptions of aging affect the health of the elderly. In one 2002 study, she and her colleagues analyzed data collected from 660 seniors over a quarter-century; those with an optimistic view of old age lived an average of 7.5 years longer than those with a pessimistic view, even after controlling for factors like overall health, socioeconomic status, and loneliness. In another study, this one from 2012, a team of researchers followed 598 people over the age of 70 as they recovered from disabling injuries or illnesses. Sure enough, those with more positive ideas of aging were more likely to make a full recovery.

Across the board, the studies pointed to the same conclusion: A person’s attitude towards old age affects how they fare once they reach it. Or, as The New York Times summed it up in a 2012 article on Levy’s work, “Old people become what they think.”

Which raises another question: Can what they think be changed?

In a study recently published in the journal Psychological Science, Levy and researchers from Yale and the University of California Berkeley set out to learn the answer by studying 100 volunteers between the ages of 61 and 99 (the average age was 81). One group of participants was asked to write a story about “a senior citizen who is mentally and physically healthy,” while another group completed a subliminal-messaging computer task where positive aging-related words—“spry” or “wise,” for example—flashed across the screen too quickly for them to detect on a conscious level. As a control, others were asked to complete neutral versions of the same activities, either writing a story on a topic unrelated to aging or watching a screen with flashes of nonsense strings of letters.

The volunteers completed their respective tasks once a week for five weeks. At the beginning of the experiment and once weekly for three weeks after it ended, they also took three different tests: one that measured their attitudes towards old age in general; one that measured their perceptions of themselves as people of advanced age; and one that tested their gait, strength, and balance, or what the researchers called “physical functioning.”

The positive aging stories, the researchers noted, improved the participants' view of aging overall, but “yielded no significant effects” on either of the other measures—for the most part, those volunteers were no better off after writing the stories than they were before, either physically or in terms of their own self-image. In fact, the only participants who saw notable differences across all categories between the beginning and end of the experiment were the ones who had been exposed to the subliminal messages. (“Implicit messages,” as the researchers phrased it, certainly seems like a friendlier term than “subliminal messages,” which typically conjures up ideas of more sinister intentions. See: George W. Bush’s “RATS” election ad from 2000, or that Simpsons episode about the Navy recruitment spot disguised as a music video.)

One reason for the difference between the so-called “implicit” and “explicit” (story-writing) groups, Levy said, may be that asking the participants to actively consider the positive aspects of aging by writing about it also caused them to call to mind the more negative stereotypes. The participants who subconsciously processed the positive words, by contrast, did so with blank slates—because they weren’t specifically thinking about aging at the time, they didn’t have anything to act as a buffer or a counterbalance, allowing them to more readily absorb the sunnier portrayal.

“When people are given messages in a very explicit way, sometimes it’s easy to resist them or just discard them as not being valid or relevant,” Levy explained. “One of the thoughts behind why these implicit messages might work is that they might be able to bypass some of the negatives, the ageism that people have taken in over time.”

But how does that unmitigated positive thinking translate to better physical health?

Often, Levy says, it has to do with health behavior. People who feel better about themselves are more likely to care of themselves; someone who feels great about aging, it’s fair to assume, would be more likely to invest time in their own well-being than someone who sees their future as a slow descent into irrelevance.

In this study, which didn’t assess health behavior, the researchers believe that the subliminal messages, as they cut through previously-held negative stereotypes, may have caused a sort of chain-reaction placebo effect. “It may be that the intervention promoted positive age views, which then might have promoted positive views of their own aging, which might then have led to physical-function improvements,” Levy explained.

“What’s interesting is that sometimes people hold stereotypes that are kind of the opposite at the same time—so for instance, old people are wise and old people are senile,” she added. “[The idea that] old people are fit and spry, and then that old people show physical decline, is certainly a strong stereotype that people have expressed in a number of studies.” But previous research has shown that subliminal messages may actually be a force for positive thinking—a 2009 study from a team of Dutch scientists concluded that the messages are effective only in motivating people to do things that they wanted to do anyway, or that seem like they would have beneficial outcomes.

So, a qualification for the Times’ proclamation that “old people become what they think”: They—like all of us—think a lot of things about aging, not all of them congruent with one another. And the terms flashing across the screen, the affirmation that they are spry and wise, may not have been actively changing minds so much as nudging them in a direction they already wanted to go.