Thought you had until at least age 50 to worry about your brain slowing down?
Well, think again (and quickly, if you can). For according to a new Canadian study, our cognitive motor skills — the ability of our brain to process and then react to new information — peaks at age 24.
After then, it’s apparently all downhill.
“Among the general public, people tend to think of middle age as being roughly 45 years of age, after which there are obvious age-related declines in cognitive-motor functioning,” write the authors of the study. “Once ‘over the hill,’ experience and wisdom, the consolation prizes of age, are hoped to be sufficient to either attenuate this decline or at least compensate for it indirectly. Aging research has shown that this general conception is incorrect. There is much evidence that memory and speed on a variety of cognitive tasks may peak much earlier.”
‘A ruthless war game’
For the study, which was published online this week in the journal PLoS One, researchers at Simon Fraser University in Vancouver analyzed thousands of hours of stored data from the performance records of 3,305 StarCraft2 players, aged 16 to 44. The game is described in an accompanying press release as “a ruthless competitive intergalactic computer war game that players often undertake to win serious money.”
StarCraft2 “brings several important advantages to the study of aging,” according to the study’s authors. It’s played in real time, for example, a factor that requires players to act and make decisions quickly. It’s also played by people of various ages and skill levels — and for sustained periods of time.
Using complex statistical modeling, the researchers figured out how long all the players took to react to the moves of their opponents. (This is one of the first scientific studies to use such “big data.”) They then compared the performances at different ages.
A matter of milliseconds
The analysis revealed, as the press release notes, “an earlier-than-expected slippery slope into old age.”
“After around 24 years of age, players show slowing in a measure of cognitive speed that is known to be important for performance,” states Joe Thompson, the lead author of the study and a psychology doctoral student, in the press release. “This cognitive performance decline is present even at higher levels of skill.”
The decline is small in absolute numbers. In fact, it can be measured in milliseconds. On average, a 39-year-old in the study reacted 150 milliseconds (.15 seconds) slower than a 24-year-old.
But that’s still a significant difference, says Thompson and his colleagues. In relative terms, the study found that for each 15 years of age, cognitive speed dropped by 15 percent — and, again, no matter what the player’s skill level.
In other words, experience did not make up for the decline in cognitive motor skills.
Something else did, however. “Older players, though slower, seem to compensate by employing simpler strategies and using the game’s interface more efficiently than younger players, enabling them to retain their skill, despite cognitive motor-speed loss,” says Thompson.
The older players relied much more heavily on keyboard shortcuts, for example, to implement their strategic decisions.
That finding suggests, says Thompson, “that our cognitive-motor capacities are not stable across our adulthood, but are constantly in flux, and that our day-to-day performance is a result of the constant interplay between change and adaptation.”
Thank goodness for that.
Thompson and his colleagues didn’t investigate the biological causes of the decline, but they speculate that it may have something to do with a metabolic shift in the “ratios of N-acetylaspartate (NAA) to choline (Cho),” which begins in the brain during the early 20s.
PloS One is an open-access journal, so you can download and read the entire study at the journal’s website.