You can always tell when someone does not have a lot of experience in something. They are anxious, they start too soon, perhaps confused. With practice and training, situations become rote. Athletes talk about how time slows down when they have locked into what they are doing.

Older brains are more experienced, obviously, and a new paper in Topics in Cognitive Science finds that rather than being a decline in brain function, older brains may take longer to process because they have ever increasing amounts of knowledge.

Dr. Michael Ramscar of the University of Tuebingen and colleagues examined the measures that are usually thought to show that our cognitive abilities decline across adulthood. Instead of finding evidence of decline, the team discovered that most standard cognitive measures are flawed, confusing increased knowledge for declining capacity.

Less is better when it comes to brain activity, but people selling us something, like brain training games, allege just the opposite. This image, about digital media brains, finds that younger brains that are working more reading on digital media, have problems conveying though. Credit and link: Jeremy Cairns.

They used computers programmed to act as though they were humans, to read a certain amount each day, learning new things along the way. When the researchers let a computer 'read' a limited amount, its performance on cognitive tests resembled that of a young adult. If the same computer was exposed data which represented a lifetime of experiences its performance looked like that of an older adult.

Often it was slower, not because its processing capacity had declined, but because increased "experience" had caused the computer's database to grow, giving it more data to process, and that processing takes time.

"What does this finding mean for our understanding of our ageing minds, for example older adults' increased difficulties with word recall? These are traditionally thought to reveal how our memory for words deteriorates with age, but Big Data adds a twist to this idea," said Ramscar. "Technology now allows researchers to make quantitative estimates about the number of words an adult can be expected to learn across a lifetime, enabling the team to separate the challenge that increasing knowledge poses to memory from the actual performance of memory itself.

"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?"