University of Illinois psychology professor Arthur Kramer, an author of the research, said the findings from the first such study of older adults are the first to show pronounced effects on cognitive skills not directly related to skills learned in the video game.

After testing several video games, the researchers selected "Rise of Nations," which gives gamers points for building cities and feeding and employing their people, maintaining an adequate military and expanding their territory.

The researchers found, overall, video game training improved participants' performance on several tests. As a group, the gamers became significantly better and faster at switching between tasks compared with a comparison group. Their working memory, as reflected in the tests, also was significantly improved and their reasoning ability was enhanced.

To a lesser extent, their short-term memory of visual cues was better than that of their peers, as was their ability to identify rotated objects.

But the scientists said the video-game training had no effect on ability to recall a list of words in order, numeration ability or ability to inhibit certain responses.

The study that included postdoctoral researcher Chandramallika Basak appears in the journal Psychology & Aging.