Different cognitive skills peak at different times over our lifespans, research finds

Here’s some promising news for anybody who’s aging (and that, of course, is all of us): A recent series of crowd-sourced experiments suggest that different aspects of fluid intelligence — our ability to think abstractly, reason quickly and solve problems — peak at different periods during adulthood.

In other words, our brains do not, as previously believed, reach a so-called cognitive peak when were in our 20s and then start an inevitable descent. Some kinds of fluid intelligence actually improve with age.

Or, as Joshua Hartshorne, a postdoctoral researcher in computational cognitive science at the Massachusetts Institute of Technology and one of the co-authors of a recent study published on this topic, explained earlier this year: “At any given age, you’re getting better at some things, you’re getting worse at some other things, and you’re at a plateau at some other things. There’s probably not one age at which you’re peak on most things, much less all of them.”

Independent trajectories

Science writer Kayt Sukel describes Hartshorne’s study (published in March in Psychological Science) in an article last week for the Dana Foundation:

The [researchers] collected data from nearly 50,000 participants who logged in to play [at the websites gameswithwords.org and testmybrain.org], and found that different cognitive skills peaked at different times over the lifespan. For example, while short term memory appears to peak at 25 and start to decline at 35, emotional perception peaks nearly two decades later, between 40 and 50. Almost every independent cognitive ability tested appears to have its own trajectory.

The study also included a vocabulary test. The peaking of that skill — part of crystallized intelligence (cognitive skills derived from learning and experience) — occurred, at least in this study, when people were in their late 60s and early 70s. For obvious reasons, crystallized intelligence has long been recognized as peaking later in life than fluid intelligence. (Experience can come only with age.) Still, the study’s results show the peak occurring much later than previously thought.

Ups and downs

As Hartshorne and his co-author, Laura Germine, a postdoctoral researcher in psychiatric and neurodevelopmental genetics at Massachusetts General Hospital, wrote in their paper: “Not only is there no age at which humans are performing at peak on all cognitive tasks, there may not be an age at which humans perform at peak on most cognitive tasks.”

“There’s old work showing age trajectories in different academic disciplines, Ulrich Mayr, a psychologist at the University of Oregon who studies aging but was not involved in the Psychological Science study, told Sukel. “More and more, we are seeing that certain aspects of abilities decline as we age and then others may get better. The general idea behind the old fluid/crystallized distinction has always been that every function basically marries those two different forces in some way. So you will see that some things will go up and some things will go down as you get older. But we don’t really understand why.”

“Aging isn’t all decline and doom,” writes Sukel.

Good to know.

You can read Sukel’s article on the Dana Foundation’s website. The Psychological Science study can be read online.