Old People's Brains Work Slower Because They Know More, Scientists Claim

Popular stereotypes suggest that as we get older, our brains go into a steady decline. However, researchers have now suggested this is not the case.

Michael Ramscar of Tübingen University has said that elderly people only think slower because they have so much more information stored in their brains.

Ramscar looked at the measurements showing cognitive abilities and found that most are highly flawed: "The human brain works slower in old age, but only because we have stored more information over time," he said.

"The brains of older people do not get weak. On the contrary, they simply know more."

Published in the Journal Topics in Cognitive Science, Ramscar and his team trained computers to read a certain amount every day and to learn new things. When they limited how much a computer could read, its performance resembled that of a young adult. However, when it was exposed to the experiences we might have over a lifetime, its performance resembled an older adult.

The 'older' computer was slower, not because it was less able to process information, but because its experience had caused its database to grow, meaning it took longer to perform tasks.

"Imagine someone who knows two people's birthdays and can recall them almost perfectly. Would you really want to say that person has a better memory than a person who knows the birthdays of 2000 people, but can 'only' match the right person to the right birthday nine times out of ten?" Ramscar said.

Addressing some previous failings of cognitive ability and aging, the researchers said older people sometimes have problems remembering names because there is far greater variety of names today than two generations ago.

A cultural shift towards more diversity means the number of different names an adult learns has increased dramatically. Computer models shows this means it takes longer to locate a name from memory than ever before.

In another test, researchers found that in word association cognitive tests, where people learn to connect certain words, younger adults often perform better. However, while the tests showed older people being slower, they also found a correlation between age and the mastery of knowledge – understanding what words meant was almost a hindrance.

Harald Baayen, head of the Alexander von Humboldt Quantitative Linguistics, where the research was carried out, said: "If you think linguistic skill involves something like being able to choose one word given another, younger adults seem to do better in this task. But, of course, proper understanding of language involves more than this. You have also to not put plausible but wrong pairs of words together.

"The fact that older adults find nonsense pairs – but not connected pairs – harder to learn than young adults simply demonstrates older adults' much better understanding of language. They have to make more of an effort to learn unrelated word pairs because, unlike the youngsters, they know a lot about which words don't belong together."