Younger people powered by 'high definition' memories

High-definition video or television set sound OK. But high-definition memories?

Yes. And these high-definition memories are what make the quality of memories in younger people better than older adults, says a study.

The elderly store information at a lower resolution than younger adults, resulting in impaired recollection.

Younger adults may be able to use perceptual implicit memory - a different kind of visual memory - to give them a 'boost' when they are trying to retrieve the stored information, said Philip Ko of Vanderbilt University in Nashville, Tennessee, US.

The research, led by Brandon Ally of Vanderbilt University, focused on visual working memory - a person's ability to briefly retain a limited amount of visual information in the absence of visual stimuli.

Their examination of why this function is reduced during the course of healthy aging took the multiple stages of encoding, maintenance, and the retrieval of memorised information into account, said the study that appeared in the journal Attention, Perception and Psychophysics.

The researchers took 11 older adults of around 67 years of age and 13 younger adults of nearly 23 years of age for a task called 'visual change detection'.

This task consisted of viewing two, three or four coloured dots and memorising their appearance.

These dots soon disappeared. Later, the participants were presented with a single dot appearing in one of the memorised colours or a new colour.

The accuracy of their response - called 'behavioural measure' - was considered to reflect how well they memorised the colours, said the study.

Ko found that behavioural measures indicated a lower capacity in older adults than younger adults to memorise items.

But the neural measure of memory capacity was very similar in both groups, he added.

"We don't know why older adults perform poorly when their neural activity suggests their memory capacity is intact, but we have two leads," Ko said.

The first result suggests that older adults retrieve memories differently than younger adults. Second, there is emerging evidence that the quality of older adults' memories is poorer than younger adults, he said.