Scientists now doubt that our brain's processing speed declines from the age of 20. Until now, they thought our brain power peaked at 20 and went down after that. Researchers said older people do not need to worry about forgetfulness. Cognitive skills are still powerful at the age of 60. The researchers said their results showed that "mental speed in contexts demanding fast and forced decisions do not decline until relatively late in [people's] lifespan".

The study used data on people aged between 10 and 80. It showed that mental processing speed remained constant until 60, but declined after then. The mental processing speed increased in people in their 20s and remained high until 60. A researcher said: "Until older adulthood, the speed of information processing…barely changed." He said older people take longer to make decisions because they are more cautious, less impulsive and less reckless.