The functional interaction of visual-perceptual and response mechanisms during selective attention in young adults, young-old adults, and old-old adults.

A response compatibility paradigm was employed to address how the perceptual and response activation processes functionally interact during selective attention and how they may be influenced by aging. The results showed that increasing the visual similarity of targets within response sets reduced the magnitude of the interference effect, but only with a narrow interletter distance. In a dissimilar condition, the magnitude of the interference effect did not vary with age. However, in a similar condition, the magnitude of the interference effect was larger for both young (18-30 years) and young-old adults (55-79 years) than for old-old adults (> or = 80 years). In contrast, all three groups showed similar facilitation effects. These results failed to provide support for the notion that enhanced spatial filtering of the target from the flankers produces a corresponding decrease in response competition. Rather, the decrease in the interference effect can be attributed to a functional interaction between the perceptual availability of partial information and the magnitude of response competition. The results also suggest that age does not impair response activation but that advanced age diminishes the availability of local, but not global, feature information.