The human mind is more resistant to the march of time than conventional wisdom suggests. Like a fine wine, some parts even get better with age.
As our brains inevitably grow older, some of our mental power is destined to fade, like spatial visualization or our mind's processing speed. Yet research has found there are other mental abilities that can improve with time, such as vocabulary and verbal comprehension.
New research among 702 participants aged 58 to 98 has now identified two fundamental brain functions that seem to get stronger as we get older.
The study had participants complete an Attention Network Test (ANT), whereby volunteers are shown a central arrow and two flanking arrows on a computer screen and asked to press a button corresponding to the central arrow's orientation as fast as they can.
A variety of cues were flashed on the screen before each arrow was shown. These included either no cue, a cue for an oncoming arrow, and a cue that hints as to where an oncoming arrow should be.
Comparing the response times of all their participants and controlling for a variety of confounding factors, researchers found older volunteers were not as good at staying vigilant in the task. They didn't respond as well to the time cue, which meant they were less prepared for the next arrow.
That said, when it came to cues that shifted the brain's attention to look at a particular point on the screen, older people seemed to be better at orienting their attention as they aged, and this was true right up until quite old age.
The older the individual, the better they also tended to be at canceling out distracting or conflicting cues that appeared on screen – a skill that improved at least until a person's mid-to-late 70s.
The researchers were testing participants' brain processes associated with alerting (being prepared to adapt to new information), orienting (shifting the brain's resources to specific locations in space), and executive inhibition (blocking out distractions to focus on something).
"We use all three processes constantly," explains psycholinguist João Veríssimo from the University of Lisbon, Portugal.
"For example, when you are driving a car, alerting is your increased preparedness when you approach an intersection. Orienting occurs when you shift your attention to an unexpected movement, such as a pedestrian. And executive function allows you to inhibit distractions such as birds or billboards so you can stay focused on driving."
The current research suggests older individuals might be slower to respond to novel situations while driving a vehicle, but they are better at staying focused and orienting their attention where needed on the road.
This ability to control one's attention is considered a higher-order brain function, and while the authors are not suggesting all executive functions remain intact or even improve in a person's 70s, it seems at least some do.
Nor is it just in the car where these forms of attention are useful. Researchers say orienting and executive control of attention are also critical aspects of memory, decision making, self-control, navigation, math, language, and reading.
"These results are amazing, and have important consequences for how we should view aging," says neuroscientist Michael Ullman from Georgetown University.
"People have widely assumed that attention and executive functions decline with age, despite intriguing hints from some smaller-scale studies that raised questions about these assumptions. But the results from our large study indicate that critical elements of these abilities actually improve during aging, likely because we simply practice these skills throughout our life."
The findings run contrary to a dozen or so other tests that have found aging impacts all three aspects of attention.
But as the authors of the current study point out, these previous trials had relatively small sample sizes and often failed to control for other factors, like sex and education.
What's more, almost all of them compared younger and older adults to each other, as opposed to focusing on the age range of interest.
Some researchers argue this is a mistake, as it means we could be overlooking variability within the age group of interest, especially since most cognitive changes don't come about until middle age rolls around.
The new research seeks to make up for these limitations. Its findings will need to be further explored, but it suggests not all forms of attention fade with age.
Because orienting attention and inhibiting attention are skills that can improve with lifelong practice, it makes sense that they would get stronger as we age.
Meanwhile, staying vigilant is a state that can't exactly be improved with practice, meaning it is more likely to decline over time.
The way that our minds change with age is clearly not as simple as we once assumed. The very same sample of participants in this study was also found to show strong declines in working memory in another study, which the authors say underscores the clear complexity of the aging brain.
"The findings not only change our view of how aging affects the mind, but may also lead to clinical improvements, including for patients with aging disorders such as Alzheimer's disease," says Ullman.
The study was published in Nature Human Behavior.