By Peter M. Vishton, PhD, William & Mary

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

What is the precise difference between the brain of an average 20-year-old and a 65-year-old? Professor Vishton reveals the findings from cognitive tests and how you can utilize your strengths as you get older so that age-related cognitive decline does not become an issue.

Age and Brain Function

Research has found that around 20 years of age, the human brain seems to peak in terms of the many basic functions that are assessed by cognitive tests. 

“Let me highlight two very important things at this stage,” Professor Vishton said. “First, I am only talking about specific tests of isolated cognitive faculties—things like memory, attention, and processing speed. I am specifically not talking about complex behaviors like writing, problem solving, engineering, inventing, creativity, and the like. In terms of many complex behaviors like these, humans usually continue to improve beyond 20 years of age.”

The opera singer Andrea Bocelli didn’t even start singing seriously until he was 34. According to most experts, his greatest accomplishments occurred almost a decade later. 

The great Julia Child started to cook seriously when she was in her late 30s and didn’t start teaching others on her famous show until she was around 50 years of age. Penicillin was invented by a guy who didn’t start seriously pursuing science until his 30s. 

It’s not that we peak in terms of our complex, real-world behavior at age 20. Isolated cognitive faculties peak at that age, but that’s much different from overall performance.

Measuring Cognitive Decline

How big is the decline in basic cognitive functions after age 20? Many researchers have found that it’s significant but a lot smaller than we used to think.

In a recent study, German psychologist Florian Schmiedek and his colleagues looked in detail at cognitive function differences of younger and older adults. They recruited a large number of participants between 20 and 30 years old and another group between 65 and 80 years old. The participants performed a variety of cognitive tests 10 different times, on 10 different days, over the course of about two months.

One of the tests involved memory. Lists of 36 words were presented, one at a time, for several seconds each. Once the list presentation had finished, the participants had to do their best to recall that list, in order. 

The score was calculated as the percentage of words correctly recalled, multiplied by a score from 0 to 1 that reflected how accurate the ordering of the words was. A perfect score would be 1. If you got all of the words correct but scrambled the order, you would be around 0.5.

This is a challenging task. Even someone with a really impressive memory isn’t likely to come anywhere close to a perfect 1.0 here. The young adults scored around 0.25. Older adults scored around 0.15. 

That seems like a big drop, but this is aimed at the very peak of our rapid encoding and memory abilities. When the task is slowed down enough, these memory differences get substantially smaller.

Minimizing Effects of Aging

One of the biggest declines in cognitive processing seems to involve speed. As we get older, we need a longer period of time to do certain tasks. As long as we have that time, many of these differences grow substantially smaller, although they never quite disappear.

“There’s a tip here—not for eliminating the effects of aging, but for minimizing those effects,” Professor Vishton said. “Take your time. As long as you don’t hurry, as long as you give your brain a little extra time, its performance will be substantially better as you age.”

It’s also worth noting that some abilities decline much more slowly than others. For example, our procedural memory—the memory for how to perform tasks—declines very slowly, and some studies suggest almost not at all. 

Our implicit memory similarly seems to barely decline at all. Implicit memory is our encoding of information and associations that seem familiar, even if we can’t explicitly remember where the knowledge comes from.

“Your procedural, implicit memory is your friend here,” Professor Vishton said. “By relying on it more, you can sidestep some of the effects of aging.”

For example, if you ever have trouble remembering someone’s name, you can try recalling it using implicit memory. As you look at the person’s face, you might not be able to remember the name, but guess to yourself what the first letter of the name is. 

Perhaps you see a man and guess J. Then start thinking of names that start with J—James, Joe, Jeff, John. At some point, you may feel a spark of recognition. 

This strategy isn’t guaranteed to work, but it is often very effective. Implicit memory isn’t ideal for remembering many things, but since it works so well as we age, this tip will help you get more out of it.

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.

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.