By Christine Hsu
"At least in some situations, 70-year-olds may have response times similar to those of 25-year olds," said Roger Ratcliff, professor at Ohio State University and co-author of the studies in a statement.
Many people think that it is natural that older people’s brains slow down as they age, but the finding contradicts common sense, Ratcliff said.
However he maintained that his results for children in decision-making are what most scientists would have expected; very young children have slower response times and worse accuracy compared to adults, but as they mature these skills improve.
Researchers evaluated speed tasks using a model that accounts for both reaction time and accuracy. Most past models have only considered either speed or accuracy.
"If you look at aging research, you find some studies that show older people are not impaired in accuracy, but other studies that show that older people do suffer when it comes to speed. What this model does is look at both together to reconcile the results," Ratcliff said.
The need for accuracy was the reason why the elderly seem to be slower at brain tasks in past research, researchers suggested.
"Older people don't want to make any errors at all, and that causes them to slow down. We found that it is difficult to get them out of the habit, but they can with practice," said Gail McKoon, professor at Ohio State and co-author of the studies.
Experiments Call for Quick Reactions
In one experiment, participants sat in front of a computer screen and were instructed to quickly judge whether asterisks that appeared on the screen were “small” or “large” in amounts, and to press one of the two keys on the keyboard depending on their answer. A small number of asterisks consisted of 31-50 dots, and a large number comprised of 51 to 70 dots.
In another experiment, participants were also seated in front of a computer and shown a string of letters, and they had to decide whether words that appeared on the screen were English words or not.
Researchers tested second and third graders, fourth and fifth graders, ninth and tenth graders, college-aged adults, and older adults from 60 to 90 years old.
They found that younger children, like the elderly took longer to make a decision than older children and young adults. However, the young children had less accurate results compared to the elderly even after taking longer to make up their minds.
"Younger children are not able to make as good of use of the information they are presented, so they are less accurate," Ratcliff said.
Older adults, although slower, were just as accurate in the decision-making tests as young adults, and this trend applied to even the oldest participants, researchers found.
"For these simple tasks, decision-making speed and accuracy is intact even up to 85 and 90 years old," McKoon said.
When researchers encouraged older adults to go faster on the asterisk and word tests the difference between young adult response time and older adult response time decreased significantly.
Aging Effects Do Take Place
However, the results do not mean that there are no effects of aging on decision-making speed and accuracy, researchers said.
Tests for accuracy in “associative memory”, like remembering a pair of words that were previously studied, showed that older people were significantly less likely to remember a pair of words shown to them earlier.
Researchers said that overall the current research sheds a brighter outlook about the cognitive skills of seniors, and disproves the theory that all cognitive processes decline at the same rate as people age.
The finding shows that older people can be trained to respond faster in some decision-making tasks without affecting their accuracy, indicating that their cognitive skills in some particular cognitive areas are just as capable as younger adults.
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