"What's the name of our neighbour? 1 can't remember right now." Have you ever heard your grandparents ask questions like this? Usually, we think older people's memories become bad because their brains get weak, but a team of scientists at the University of Tubingen in Germany has a different idea.
"The human brain works slower in old age," said lead scientist Michael Ramscar, "but only because they have stored more information over time."
The findings are based on a series of computer simulations(模拟)of learning and memory. Scientists let the computers read a certain amount of words and learn new things each day. When the computer "reads" only so much, its performance on cognitive(认知)tests is similar to that of a young adult. But if the computer learned the experiences we might have over a lifetime, its performance is similar to that of an older adult.
Often it was slower because increased "experience" had caused the computer's database(数据库)to grow, giving it more data to process-which takes time. This is similar to old people. Imagine a person knows two people's birthdays. Another person knows the birthdays of 2,000 people, but can only match the right person to the right birthday nine times out of 10. Can you say the first person has a better memory than the second person?
The basic idea is that "The larger the library you have in your head, the longer it usually takes to find a particular word." Benedict Carey, a science reporter, wrote in an article about the study.