The brains of older people do not get weak as they age. On the contrary, they simply know more.
Debunking earlier theories that our brains go into a steady decline as we age, researchers have found that the human brain works slower in old age but only because it has stored more information over time.
"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," said professor Harald Baayen, who heads the Alexander von Humboldt Quantitative Linguistics research group.
According to him, proper understanding of language involves more than this.
"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," Baayen added.
The elderly have to make extra effort to learn unrelated word pairs because, unlike the youngsters, they know a lot about which words do not belong together, said the study published in the journal Topics in Cognitive Science.
"Technology now allows us to make quantitative estimates of the number of words an adult can be expected to learn across a lifetime," said Michael Ramscar of Tübingen University, Germany.
"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 2,000 people, but can 'only' match the right person to the right birthday nine times out of ten?" asked Ramscar.
The answer appears to be 'no'.
Ramscar's team trained their computer models on huge linguistic datasets. They found that standardised vocabulary tests - used to take account of the growth of knowledge in studies of aging - massively underestimate the size of adult vocabularies.
The researchers found that to get their computers to replicate human performance in word recognition tests across adulthood, they had to keep their capacities the same.
"Forget about forgetting. If I wanted to get the computer to look like an older adult, I had to keep all the words it learned in memory and let them compete for attention," explained Tübingen researcher Peter Hendrix.
"We need different tests for the cognitive abilities of older people - taking into account the nature and amount of information our brains process," said the study.
