Our Brains Stay Sharp Much Longer Than Thought

Don't let the youngins tell you your brain is slower than molasses. Though plenty of research shows response times slow beginning around the age of 20, that doesn't necessarily support the widely held view that brain processes slow from that age. Indeed, a new study finds this slowing in response times might simply be because, with age and wisdom, people become more cautious in their decision-making. So when do we see mental processes significantly decline? Turns out, it's much later in life, around the average retirement age, according to the study published Thursday in Nature Human Behaviour.

In analyzing reaction times of more than 1.1 million people who took part in an online experiment requiring them to place words and images into one of two categories with the press of a key, researchers did find the average time for a correct response peaked around the age of 20. But they suggested this was because young adults were "most willing to trade accuracy for speed," per the Guardian. In other words, they didn't think too hard before pressing the key. Up to the age of 60, participants became more accurate but slower due to what researchers concluded were "increases in decision caution" and slower motor processes involved in pressing the key, "rather than to differences in mental speed."

Mental speed appeared to peak around age 30, but "until older adulthood, the speed of information processing in the task we studied barely changes," lead author Dr. Mischa von Krause of Heidelberg University tells New Scientist. "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," he adds. Boston College psychologist Dr. Joshua Hartshorne, who was not involved in the study, says it "joins a body of work suggesting that the way mental abilities change throughout life is complicated," per the Guardian. "But whatever's going on, it's definitely not that we peak at 20 and go downhill from there." (More neuroscience stories.)