058 An old person talking on his mobile phone. 050609. Picture: Bongiwe Mchunu

London - You might have thought that people of 70 aren't as mentally quick off the mark as they used to be. Well think again.

They can have reactions as fast as 25-year-olds, a study reveals.

It has previously been established that both children and the elderly tend to have slower response times when they have to make quick decisions in some settings.

But the latest research suggests that much of that slower response is a conscious choice to emphasise accuracy over speed.

In fact, healthy older people can be trained to respond faster in some decision-making tasks without hurting their accuracy - meaning their cognitive skills in this area are not so different from younger adults.

One of the study's authors, Roger Ratcliff, professor of psychology at Ohio State University, said: "Many people think that it is just natural for older people's brains to slow down as they age, but we're finding that isn't always true. At least in some situations, 70-year-olds may have response times similar to those of 25-year olds."

Prof Ratcliff and his colleagues have been studying cognitive processes and ageing in their laboratory for about a decade. In a study published online this month in the journal Child Development, they extended their work to children.

Prof Ratcliff said their results relating to youngsters are what most scientists would have expected - very young children have slower response times and poorer accuracy compared with adults, and these improve as the children mature.

But the more interesting finding is that older adults do not necessarily have slower brain processing than younger people, said Gail McKoon, professor of psychology at Ohio State and co-author of the study.

"Older people don't want to make any errors at all, and that causes them to slow down," she said. "We found that it is difficult to get them out of the habit, but they can with practice."

Prof McKoon added that for the simple tasks used in the study, "decision-making speed and accuracy is intact even up to 85 and 90 years old". - Daily Mail