Scientists have cast doubt on a common belief that the brain's processing speed declines from the age of 20. Until now, scientists believed our cognition level peaks at 20 and declines thereafter. Lead researcher doctor Mischa von Krause gave hope to older people who worry about forgetfulness or reducing brain power. He said cognitive skills were still powerful at the age of 60. He wrote: "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."

The study used data on 1.1 million people, aged between 10 and 80. The results showed that mental processing speed remained constant until the age of 60, but did start to decline after. The researchers said mental processing speed increased in people's 20s and remained high until 60. Dr von Krause said: "Until older adulthood, the speed of information processing…barely changed." He said older people taking longer to make decisions may be because they are more cautious, less impulsive and less reckless. The study could cast light on diseases such as Alzheimer's.