Older adults tend to score lower on tests of mental function, a phenomenon that was long-attributed to be a symptom of age-related cognitive decline—a serious but common problem. However, recent research proposes a new theory to explain why older adults score lower on cognitive tests: Like a computer jam-packed with photos, videos and text files, the longer we live, the more our minds fill up with information.

As we age, we have more of these mental "files" to sort through: We've been exposed to—and hopefully retained—more facts, experiences, and wisdom. And since quickness is a metric in many widely-used cognitive exams, is it possible that older adults' performances indicate something other than a troubling mental decline?

According to the authors of a paper published in Topics in Cognitive Science, the answer is yes.

"Older adults' changing performance reflect memory search demands, which escalate as experience grows. Our results indicate that older adults' performance on cognitive tests reflects the predictable consequences of learning on information-processing, and not cognitive decline."

The Experts Weigh In

Richard Isaacson, MD, director of the Alzheimer's Prevention Clinic at NewYork-Presbyterian Hospital/Weill-Cornell Medical Center in New York City, called the paper "an interesting and moderately compelling theory for cognitive decline that is not due to a disease like Alzheimer's."

"Typically, people experience a cognitive slowdown as they age," says Alan Manevitz, MD, clinical psychiatrist at Lenox Hill Hospital in New York City. He likens this deceleration to the physical changes older people also commonly encounter: "If you fall when you're 80, you are more likely to break a hip than if you take a fall when you are younger," he explains. "People slow down physically and mentally, and all aging humans will develop some degree of cognitive decline."

While the theory outlined in the Topics in Cognitive Science paper is interesting, Isaacson says it does not account for all cases of cognitive decline: "Alzheimer's is a leading cause of cognitive decline, and so are other disorders such as vascular disease," he says. So if an individual has noticeable changes with memory or thinking skills, an evaluation by a primary care doctor or a specialist is recommended. "This isn't something to be scared of," Isaacson adds. "There's a lot that can be done to treat memory loss and to slow it down. And certain things are reversible when it comes to memory function."

What You Can Do

These steps may reduce your risk of cognitive decline. To stay sharp and focused:

  • Eat less in general.
  • Eat fewer refined carbohydrates such as white bread, white rice, and white pasta.
  • Eat more leafy greens, and eat berries on a regular basis.
  • Enjoy caffeinated coffee with dark cocoa powder stirred into it. "Dark cocoa powder by itself not only improves memory, but blood pressure and insulin resistance, too," Isaacson says. "And coffee is known to help with memory, which is why I tell my patients, 'Mocha in the morning for memory.'" When you make your mocha coffee at home, stir in a little milk, but avoid using cream and sugar.
  • If you smoke, quit. Smoking leads to problems with your arteries, and this can lead to blood vessel disease, which can progress to vascular dementia.
  • If you have high blood pressure, take steps to bring it back into the normal range, and if you are overweight or obese, lose those extra pounds. Both obesity and high blood pressure have been linked to mild cognitive decline.

Richard Isaacson, MD, reviewed this article.

Sources:

Hills, Thomas. "The myth of age related cognitive decline," Live Science. Web. Accessed 28 January 2014. http://www.livescience.com/42910-the-myth-of-age-related-cognitive-decline.html)

Ramscar, Michael et al. "The Myth of Cognitive Decline: Non-Linear Dynamics of Lifelong Learning," Topics in Cognitive Science. Web. Accessed 13 January 2014.
http://onlinelibrary.wiley.com/doi/10.1111/tops.12078/abstract

Ramscar, Michael. "The myth of cognitive decline."http://csjarchive.cogsci.rpi.edu/Proceedings/2013/papers/0230/paper0230.pdf