It’s usually assumed – and backed up by a large body of research – that thinking speed peaks when we’re in our twenties, after which it’s downhill all the way. But a massive new study using machine learning came to a different conclusion that will certainly please all middle-aged folks.
According to the new research, central processing speed remains constant throughout your life and only starts to decline after the age of 60.
Here’s the hopeful story…
Psychologists from Heidelberg University in Germany applied their machine learning mathematical model to data gathered from a study containing nearly 1.2 million participants.
Men, women, and children aged between ten and 80 sat in front of a computer and answered very simple questions that can be responded to rapidly. The questions related to words and images that flashed up on the screen.
The psychologists analyzed how long it took the participants to push the keyboard button to answer the questions and how accurate they were in their answers.
The findings, as the authors write in research published in the journal Nature Human Behaviour last month, “stand in pronounced contrast to previous findings on age differences in mental speed.”
Older People Deliberate More
The researchers found that after the age of 20 the brain did take longer to make decisions. But this was not due to a slowdown in the speed of information processing as once believed. The decrease in reaction time happened because after that age more certainty is increasingly sought before committing to an answer.
In fact, the researchers found that people’s mental speed increased in their twenties, peaked at age 30 and remained high until the age of sixty, only declining thereafter.
There are also two other aspects to brain aging not included in most other studies: The fact that visual information takes longer to travel from the eyes to the brain, and that it takes longer for people to physically hit the keyboard buttons with their fingers.
Senior author Mischa von Krause said, “Until older adulthood the speed of information processing in the task we studied barely changes. People become more cautious in their decisions with increasing age – they try to avoid mistakes.
“At the same time, the motor processes – the pressing of the response keys in an experiment – slows down with increasing age.
“Our finding is encouraging as our results show that average levels in mental speed in contexts demanding fast and forced decisions do not decline until relatively late in the lifespan.”
Although these findings contradict nearly all others, they are in accordance with some smaller studies that also found the slowdown in mental speed occurs after age 60 and not before.
What the Experts Say
Several different memory experts were asked to comment on this study.
Roger Ratcliff, a Distinguished University Professor in the Department of Psychology at Ohio State University, said, “The work replicates what has been done before but with much larger numbers of people and so provides strong converging evidence for the earlier results.”
Meanwhile, Joshua Hartshorne, Assistant Professor of Psychology at Boston College, was impressed with the machine learning method. He believes the new results could prompt a reevaluation of earlier findings.
“This joins a body of work suggesting that the way mental abilities change throughout life is complicated and we don’t really know what’s going on,” he said. “But whatever’s going on, it’s definitely not that we peak at 20 and go downhill from there.”
And that’s great news for all of us.