Keeping their edge

Older people may take longer than younger people to pick out a face in the crowd, but they may be able to more quickly assess an overall scene, such as the movement of a football team across the field or the flight direction of a flock of birds. The new findings challenge the idea that all mental functions decline with age.

“Don’t assume that someone is always slower because they have gray hair,” says Allison Sekuler, a neuroscientist at McMaster University in Hamilton, Canada, who led the study.

Her team tested two groups’ ability to determine the direction of a series of colored bars moving across a screen. When the bars were small or of a similar color to the background, younger people (who had a mean age of 23) were faster at determining movement direction. However, when the bars were larger or of high contrast, older people (who had a mean age of 68) performed faster. The results indicate that older people are better at seeing the big picture, while younger people tend to focus on the smaller details.

Sekuler and colleagues think this difference is due to an age-related decrease in a brain chemical that inhibits signals between brain cells.

In the future, the team wants to see if it can temporarily turn older brains into young ones and vice versa by giving people drugs that turn levels of this chemical messenger up or down.

The research was published in the Feb. 3 issue of the journal Neuron.