Aging and the scope of visual attention

To discover whether some cognitive deficits associated with aging could be related to a restricted scope of visual attention.

Cross-sectional study, with subjects in each age group receiving the same four conditions.

24 elderly (mean age 65.2 years, 12 men and 12 women) and 24 young (mean age 21.8 years, 12 men and 12 women) matched for handedness, gender, and education level.

SUBJECTS viewed a display that contained four light-gray squares arranged as if on the tips of a plus sign, then black X marks appeared and the subjects indicated whether one or two Xs appeared in the squares as quickly and accurately as possible. The time to respond and accuracy level were recorded. Two types of displays were used; one with squares spread out over a large area and one with squares condensed into a small area. In two thirds of the trials the size remained the same (with half being large, and half small), and in one third it changed (with half of these trials changing from large-to-small and half from small-to-large).

In the trials that had a consistent display size, the elderly subjects performed the task better with the smaller display, whereas the young subjects performed equally well with both sized displays. In addition, the elderly found it easier to shift from large to small scope than to maintain attention at the large scope; in contrast, the younger subjects found it easiest to maintain attention on a static display size.

The elderly prefer to focus attention on a smaller region of space than do younger people.