Water Cooler: Aging brains and how to keep them sharp

People often describe aging with the term “slowing down” not only to describe their day-to-day activities as kids grow up and careers turn into retirement, but also when it comes to their cognitive function.

This is largely due to your brain thinning out as you age. That’s right, it’s not just thin hair you have to worry about. Most research indicates that on average, a person’s brain loses about 5% of its volume per decade after the age of 40. In patients with degenerative brain diseases, this happens at an even higher rate. Neurons get old and die, which leaves you with a lack of brain density and neural plasticity, or the ability to form and reorganize synaptic connections between neurons. Similar to the way our bodies lose the ability to regenerate and grow as we age, the brain does too. It is tough to swallow at times, but it is also a natural part of our life cycle.

Among the aspects of cognitive function that worsen the most as humans age are perception, pattern recognition, speed of reasoning and short-term memory for words spoken aloud. Even those in their late 30s tend to score significantly lower than those in their 20s on these measures.

However cognitive studies that test for vocabulary use and retention as well as the ability to do crosswords actually improved with age. Psychologists posture that this is because these skills are part of what is called “crystallized intelligence,” which is created by knowledge that is the product of thinking and learning over the span of many years.

This concept was introduced in 1963 by Raymond Cattell, who theorized that general intelligence can be categorized into two subdivisions, fluid intelligence and crystallized intelligence. Fluid intelligence involves cognitive ability to solve reasoning problems, learning new information and overall comprehension. Crystallized intelligence deals more in the ability to deduce connected ideas from previously learned knowledge. Fluid intelligence peaks around age 20 and then begins a gradual decline whereas crystallized intelligence typically increases gradually and remains stable until about the age of 65 when it then begins to decline.

However, not all cognitive skills decline with age. Researchers have found that social reasoning or the ability to reason about social conflicts and dilemmas actually improves as humans age. This may be part of the reason why many cultures associate elders with wisdom. Older people tend to make better use of higher-order thinking when assessing social situations, which refers to the use of complex judgmental skills like critical thinking and problem solving. This type of thinking expresses a stronger need for the analysis of multiple perspectives, giving older people an advantage when it comes to counseling and intergroup negotiations. So give credit where it is due – an aging brain isn’t an exclusively negative part of life.

There is also research that has shown some fluid intelligence abilities can be retained while aging, or even improved. These studies measured the same people over time; however, it is important to note it is possible that those with more progressed cognitive decline were more inclined to drop out of the study, so there is a possibility for skewed results.

The phrase “use it or lose it” permeates our culture as a method for skill retention, and there is actually some research that upholds its validity. It’s no way to turn back the clock, but it can slow decline. Within this line of thinking, there tends to be an emphasis on training specific skills like processing speed or memory for preventing cognitive decline, but studies show that practicing those skills really only sharpen those specific skills rather than improving overall cognitive ability.

To “keep sharp” and maintain general cognition, a variety of activities are recommended like physical exercise and social engagement. Groups in studies focused on the benefits of exercise showed that active people did better with executive function, but it didn’t make much difference when it came to processing. Executive function refers to cognitive processes that help us control behavior and to select the behavior that best facilitates the attainment of goals. An example of impaired cognitive control would be a struggle with addiction or neurodevelopmental disorders like ADHD. Executive functions therefore relate to a variety of cognitive processes such as control over attention, the ability to tune out stimuli to focus on the task at hand, control of impulses, use of working memory and the ability to entertain more than one concept at one time.

Having large social networks and more social interaction overall has been related to many benefits such as better cognitive function, reduced risk of developing dementia. This applies to leisure socialization, but it also is linked to social engagement when it comes to having jobs that require complex thinking in addition to engagement.

So we can’t avoid “slowing down” as we age because atrophy of the brain inevitably happens, but using a combination of physical activity, mental training and social engagement can all help. Quarantine may make some of these things more difficult, but fitting in ways here and there to provide your brain with activity and exercise is proven to be worth it.