By Peter M. Vishton, PhD, William & Mary

Edited by Kate Findley and proofread by Angela Shoemaker, The Great Courses Daily

Is it true that our brain declines as we get older? Professor Vishton introduces a new twist to the data that might cause you to rethink your assumptions.

Cognitive Decline and Alzheimer’s

Cognitive studies have found that aging of the brain results in lowered performance in terms of memory, attention, and processing speed. However, mathematical cognitive scientists have recently addressed how Alzheimer’s disease factors into age-related cognitive decline.

Among the young adult samples in many cognitive studies, the odds that there are any participants in the early stages of Alzheimer’s disease or other age-related dementia is essentially zero, while the odds that there is someone in the older adult sample in the early stages of the disease is actually quite high. If one in 20 of the participants is affected, then in a sample of 100 participants, it’s likely that several have these diseases.

Alzheimer’s disease and related dementias can be devastating to the brain and physical health. As tragic as these diseases are, the brains of most older adults are thankfully not afflicted with them. 

If you look at the average performance of the older adult group, however, the small number of adults with dementia—perhaps early-phase, undiagnosed dementia—will tend to pull that general average down a lot. If this effect is factored out of the mean, the differences between younger and older brains grows much smaller—in some studies, the effects vanish altogether.

Self-Fulfilling Prophecies

Imagine for a moment that you believed, for some reason, that your right arm was declining in terms of its basic function, that you believed it was getting weaker, less coordinated, and more likely to make big mistakes whenever you tried to use it. How would this belief affect your behavior?

If you’re like most people, you would start using your right arm a lot less. If there was something you wanted to do and do well, you would probably use your left arm. Worse still, you might just try to do fewer things out of fear that your declining right arm would cause problems. 

Your belief that your right arm was declining would become a self-fulfilling prophecy. Eventually your right arm would actually decline, as your muscles would atrophy from lack of use. The same thing can happen if you believe that your brain is declining with age, even if your brain is declining only a little and maybe not initially declining at all.

Challenging Age-Related Brain Decline

Professor Vishton encourages you to fight against the creeping belief that your brain is declining as you age. Modern society will give you subtle messages that it is. 

Old people are often portrayed on television and in movies as doddering, sedentary, and sometimes generally confused. The scientific literature contains a lot of data to support this assertion, but that data is contaminated by this frequent tendency to not consider healthy versus unhealthy subgroups within the aging population.

According to Professor Vishton, you should presume, until proven otherwise, that your brain is declining only slowly, if at all, as you age. Not only will this tend to broaden the types of experiences you have, but it’s also likely to minimize the age-related cognitive decline itself. 

If you catch yourself thinking, “I can’t do that sort of thing at my age,” then stop and replace that thought. Maybe you can even say aloud, “I’m not sure if I can do that sort of thing at my age, but there’s only one way to find out.” As our marketing friends at Nike would say, “Just do it.”

This article was edited by Kate Findley, Writer for The Great Courses Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for The Great Courses Daily.

Peter M. Vishton is Associate Professor of Psychology at William & Mary. He earned his PhD in Psychology and Cognitive Science from Cornell University. Before joining the faculty of William & Mary, he taught at Northwestern University and served as the program director for developmental and learning sciences at the National Science Foundation.