New York, Nov 27 (IANS): One reason why learning may become more difficult as people age is because the elderly learn more than they need to, contends a fascinating study.

Older learners have the mental flexibility needed to learn a visual perception task, but they are not as good as younger people at filtering out irrelevant information, the researchers found.

"The hope is that maybe what older people need to do is to learn a skill to avoid learning what is not necessary," noted corresponding author of the study Takeo Watanabe, professor at Brown University.

The findings undermine the conventional wisdom that the brains of older people lack flexibility, or "plasticity."

The researchers enrolled a group of 10 people in the 67-79 age group and another group of 10 people in the 19-30 age group for an experiment.

Over a nine-day period, they trained on a simple visual exercise: Shown a quick sequence of six symbols - four letters and two numerals - volunteers were asked to recall the numerals they saw.

Older people improved as much as younger people on the relevant task of identifying the two numerals.

But in this study, when it came to the irrelevant skill of discerning the prevailing direction of dot movement, older people learned that, too, even when it was at its most obvious.

In a test measuring the ability to find a relevant stimulus amid a number of distractors, the researchers found that older people did notably worse than younger ones.

The attentional systems for filtering out irrelevant stimuli were indeed weaker in older learners, the researchers found.

The study appeared in the journal Current Biology.