HEIDELBERG, Germany — If you think people start to “slow down” during middle age, think again! A new study finds the brain actually continues to function at roughly the same speed for several decades. In fact, researchers from Heidelberg University say cognitive performance only starts to decline after the age of 60.
Mental speed generally refers to the speed at which people deal with situations that require them to make decisions rapidly. A team of psychologists used a large-scale online experiment with over a million volunteers to reach the conclusion that mental speed stays stable between the ages of 20 and 60 — adulthood.
The discovery has the team questioning the perception many people have that mental speed starts to slow down much earlier in a person’s life.
“The common assumption is that the older we get, the more slowly we react to external stimuli. If that were so, mental speed would be fastest at the age of about twenty and would then decline with increasing age,” says Dr. Mischa von Krause, a researcher in the Quantitative Research Methods department at Heidelberg’s Institute of Psychology, in a university release.
The brain seems slower because people become more cautious
To examine thinking speed, researchers evaluated an American experiment which actually examined implicit bias. The participants had to press a button to sort pictures of people into the categories “black” and “white.” They also had to sort words into piles labeled “good” and “bad.”
For their purposes, Dr. von Krause says the content of the test was not the important part. The German researchers were more interested in each person’s response time when making cognitive decisions. The results show that response times did increase among older participants. However, the team says there’s a reason for this that has nothing to do with a person’s brain slowing down.
“Instead, we think that older test subjects are mainly slower because they reply more cautiously and concentrate more on avoiding mistakes,” Dr. von Krause explains.
Unlike the brain, though, physical reflexes do appear to decline throughout a person’s adult life. Older participants in the experiment took longer to press the right button after making a decision. Overall, study authors say they only noticed a progressive decline in information processing speed in adults over the age of 60.
“It looks as though, in the course of our life, we don’t need to fear any substantial losses of mental speed – particularly not in the course of a typical working life,” Dr. von Krause concludes. “Generally speaking, we should also note that the test subjects in all age groups included individuals with high and low mental speeds. Our results relate to the average trend.”
The study is published in the journal Nature Human Behaviour.